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    Archived pages: 87 . Archive date: 2013-05.

  • Title: Backyard Astronomy
    Descriptive info: .. Backyard Astronomy.. Home.. Navigation.. Astrophotography Gallery.. How to Get Started.. My Equipment.. Collimating your Reflector.. Drift Alignment.. Using SLR Lenses.. Peltier Cooling the DSI Pro.. Radio Astronomy.. The Schumann Resonance.. Natural Radio Receiver.. Compass Magnetometer.. SID Receiver.. Sprites & Other TLE's.. Clear Sky Clock.. Space Weather.. Local Weather at My QTH.. Links Page.. Sign The Guestbook.. Solar Activity.. Solar X-rays:.. Geomagnetic Field:.. Quick Links.. QCUIAG Home.. Webcams for Astronomy.. Hubble Home.. My live VLF receiver stream.. Introduction.. Hello, my name is Joel Gonzalez and welcome to my website.. This website is dedicated to the art of astrophotography with a sprinkling of other astronomy related subjects.. I will be the first one to tell you that I don't do this hobby justice.. From my experience I have found that quite literally the sky is the limit when it comes to astrophotography.. The Lagoon Nebula.. The inherent difficulty of astrophotography would imply that expensive equipment is needed to achieve good results.. Ultimately, how much you end up spending depends on how far you want to go with this hobby.. Nevertheless, I have discovered that it is possible to take stunningly beautiful pictures of celestial objects with very modest equipment.. Before I get ahead of myself I would like to share how I got into this hobby.. At age fourteen I was given a used Jason refractor (800mm focal length) with a chipped main lens by my aunt.. My aunt saw how intrigued I was with the thing and just gave it to me.. I spent countless hours star gazing with my small telescope and also started delving into astrophotography with an old Fujica ST-701 35mm SLR camera.. I had no motorized mount at the time so all of my astrophotos were of star trails.. Nevertheless, these early exercises taught me a great deal about photography in general and the effects of exposure times in particular.. I had a fourteen year hiatus from astronomy, but around early December 2006  ...   Well, I was having problems with all of them and then some!.. Then I began to come across numerous websites where others were using webcams and special software with astounding results.. I modified an old Creative webcam so it would attach to the focal tube of my telescope and tried my luck with this new approach.. I had some initial success with photographing the Moon and Saturn, albeit not great success.. The most important lesson I learned from this early testing was that by using a webcam and software it is possible to control star trailing to a certain extent.. With my 35mm camera any movement of the telescope while the shutter was open translated into a hideous star trail which was additive so long as the shutter stayed open.. On the other hand, with a webcam and software one can take many shorter exposures and then integrate them via software minimizing star trailing to a great degree.. I then came across the great work done by.. Martin Burri.. on the Logitech QuckCam Pro 3000.. Martin was able to modify this webcam for long exposures by using a similar technique invented by.. Steve Chambers.. and his colleagues at.. QCUAG.. I immediately purchased one of these webcams from eBay and performed the long exposure modification by following Martin's directions.. found here.. I am now using a Meade DSI Color CCD camera for imaging and a Meade DSI Pro monochrome CCD camera for guiding.. As effective as the Logitech QC Pro 3000 is with the long exposure modification, it's still not very sensitive.. Basically, the exposure times needed to bring out detail in some deep sky objects can become problematic at times.. Things like amp glow and noise tend to put a limit on how long of an expose one can take.. The Meade DSI cameras are simply superior in this respect and are also inexpensive to acquire now.. Copyright 2006 Backyard Astronomy | All rights Reserved.. Joel.. Gonzalez@backyardastronomy.. net..

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  • Title: Backyard Astronomy Home
    Descriptive info: Backyard Astronomy Home.. Astrophotography images by Joel Gonzalez.. Equipment.. Galaxies.. Moon.. Nebulas.. Planets.. Star Clusters.. Stars.. Comets&Asteroids.. Milky Way.. Sun.. Terresrial.. Photo album created with.. jAlbum 10.. and.. Galleria.. Sponsored by:.. singaporelisted.. com..

    Original link path: /gallery/index.html
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  • Title: How to Get Started
    Descriptive info: Getting Started with Astrophotography.. Although it is not necessary to use a telescope to take astrophotographs, having one gives you more options.. For example you could just use a 35mm film SLR camera mounted on a tripod and have fun just taking long exposure photographs of the night sky.. Sure, the pictures will be of star trails as the sky moves above you, but so what! This is how I started in astrophotography.. 35mm Film SLR Camera.. Acquiring a decent telescope with a motorized mount, an equatorial mount if possible, literally opens the sky for you.. With such a telescope you could minimize star trailing by piggybacking your SLR camera to your telescope and allowing the motorized mount to track the stars as they move above you.. If you are really ambitious, you can always try your hand at eyepiece projection or even prime focus astrophotography.. Now I'm going to be truthful here, once you start delving into this realm of astrophotography things start to get more challenging.. Due to this, the best thing to do at this point is purchase a web camera, or one of the many commercial digital cameras that are geared for this purpose.. For example,.. Meade's LPI or DSI.. digital cameras are examples of such devices.. The picture to the left is of my Fujica 35mm film SLR camera with a Meade camera adaptor attached.. I have found this setup to be very sensitive to mount gyrations, so a very steady mount is absolutely required if you plan on using 35mm film for astrophotography.. In my case I decided to go the inexpensive route and purchased a Logitech QC Pro 3000 webcam.. Be sure that whatever webcam you buy it uses a CCD sensor chip as opposed to a CMOS sensor chip.. This is because CCD based webcams are much more sensitive under darkened conditions.. The best way to utilize these web cameras is to take the screw on lens that comes with them off and screw on a telescope to webcam adapter which can be purchased either from.. Mogg.. or other suppliers.. Such an adapter is pictured below.. Once the adapter is in place you can simply slide the webcam into the focuser tube of the telescope and begin prime focus astrophotography.. You will soon notice that no matter what you do to the webcam software to increase the webcams ability to detect dim objects you will hit a brick wall.. Now I'm talking about deep sky objects, you will have no trouble photographing planetary objects like Saturn, Jupiter and the Moon.. Anyway, I recommend you spend a good deal of time getting to know your setup by photographing planetary objects before you move up to DSO photography.. Webcam Adapter.. It is important to add what software you can use to assist in taking planetary and DSO imagery.. I use a few different software packages, but it is entirely up to you which one you prefer.. I like to use.. K3CCDTools.. AstroVideo.. as my primary image gathering software.. Depending on the application I will use one or the other.. In astrophotography it is common practice to do image processing after capturing the initial images.. This involves aligning, stacking and summing up the many images taken during a session.. K3CCDTools and AstroVideo have this capability built in, but it is possible to use software that is specifically designed for this purpose.. I use.. Registax 4.. to do alignment, stacking, and other work depending on what I'm trying to accomplish.. I also use PhotoShop 7 for post processing of the stacked and aligned images.. There is a lot of software out there catering to astrophotography, some free some not, so just search around until you find something that fits your needs.. If you are ready for the DSO challenge you will need to somehow get long exposure capabilities.. There are different ways of getting this, one example being to buy a camera with this capability such as the Meade DSI.. This route tends to get very expensive very quickly, so I opted to go the more inexpensive route again which was to just modify my Logitech Pro 3000 for long exposure capabilities.. Not all webcams can be modified for long exposures so it will be necessary to research before purchasing a webcam for this purpose.. I used.. to get a list of modification friendly webcams to make my decision.. Logitech Pro  ...   to keep air flowing through the circuits inside.. As can be seen in the picture to the right, the webcam is configured for prime focus work.. Prime focus means that the webcam gets inserted directly into the the focus tube without the use of an eyepiece.. This will give you a rather high degree of magnification depending on the focal ratio of your telescope.. In some situations this high magnification is a good thing, but in others you might want to get a wider field of view.. Due to this I decided to get an Atik x.. 5.. focal length reducer.. These screw on lenses effectively reduce the focal length of your telescope making it faster.. Here is.. a good explanation of how a focal length reducer works along with a good explanation of how a barlow lens works.. In the photo above of the webcam adapter you can see that I have my focal length reducer attached to the adapter.. I wanted to display how simple it is to add one of these to your setup.. Using a focal length reducer allows more light to reach the CCD imaging chip, so this is good news for astrophotography! You will notice that many astrophotgraphers use focal length reducers, this is one reason why.. Webcam Scope Mount.. I like to take wide field photographs of the sky.. Well, wider shots than what is capable with a telescope anyway.. One way which I have been able to accomplish this is by the use of a 55mm 1:1.. 8 lens.. I use the same lens that came with my Fujica SLR camera which is pictured above.. I had purchased a webcam to T-ring adapter for use in eyepiece projection work, and it just so happens that it screws right into my Fujinon lens.. To the left is a picture of how I was able to piggyback my Logitech webcam and wide field lens to my telescope.. I have just enough room between the adaptor and the lens for placing my IR cut filter or H-alpha filter in between the two.. It's amazing what a difference it makes in picture quality when the IR cut filter is used.. Webcams are most sensitive in the IR range, so if this range is not filtered out you end up with reddish pinkish looking photographs.. In the process of experimenting with wide field photography I came across what is called 'field rotation'.. This is the rotation of the field of view (FOV) over time.. With an alt-az mounting system that does not control for field rotation, if tracking is otherwise perfect, the stars and other objects in the FOV will pivot around the center of the FOV during a CCD or film exposure or during a visual observing session.. This is a big problem when it comes to astrophotography, and limits the effective length of your exposures.. The best way to fix the field rotation problem is to use an equatorial mount and is the reason why I recommended the use of one earlier.. Even equatorially mounted systems will suffer from field rotation if polar alignment is imperfect though, so care must be taken during the alignment process of equatorial mounting system.. This will ensure that field rotation will be minimized or done away with entirely.. There is another way to solve the field rotation problem which I feel needs mentioning as it negates the need for an equatorial mount.. Software such as K3CCDTools3 and Meade's Envisage v5.. 85 capturing software have the ability to cancel out field rotation.. This is accomplished by setting two points on opposite sides of the captured images.. The software then calculates the amount of rotation on each image and corrects all images before producing the final summed image.. Of course, this approach has its limitations.. Very long exposure times will display field rotation in each image making it impossible to fix with software.. This is why a good equatorial mount is still recommended for astrophotography.. Nevertheless, when taking shorter exposure times of around a few minutes software based field rotation correction can come in very handy.. I have only scratched the surface of astrophotography here, and I'm still learning myself.. My best advice is to experiment, and then experiment some more.. Most importantly, be patient.. This is a very challenging hobby, and this very fact is what makes it so great!.. So clear skies, and happy experimenting..

    Original link path: /getting_started.html
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  • Title: My Equipment
    Descriptive info: My Astronomy Equipment.. My latest astrophotography setup consist of an Orion 8 f4.. 9 Newtonian reflector, a Meade 80mm f10 refractor for guiding and an Orion Atlas EQ-G mount.. The telescope's clear aperture is 203mm, and its focal length is 1000mm.. The 80mm guide scope has an 800mm focal length.. I use a X.. 5.. Orion 8 Newt Reflector.. focal length reducer to allow for a larger field of view for guiding.. When using the Meade DSI camera in prime focus with the Orion 8 telescope my resolution is 1.. 547 arcsecond per pixel.. This gives me a field of view of around 16 by 12 arcminutes.. The Meade DSI uses a small CCD imager and this can be a problem when imaging larger DSOs.. The Orion Atlas EQ-G mount is an amazing mount for the price.. I have been impressed with its stability, slewing smoothness and ease of use.. EQMOD.. to control the mount from my laptop.. I do not use the supplied hand controller.. The EQMOD project is a great resource and the guys there have provided a great service for amateur astronomers.. With their software it is possible to control all aspects of your EQ-G mount with rather advanced features and options.. Meade DSI CCD Camera.. For the main OTA rings I'm using Orion rings and for the guide scope I am now using ADM rings from.. ADM Accessories.. Initially I was using guide scope rings from Orion as well.. These rings though are not adequate for long exposure times.. With them I was not able to take exposures any longer than two minutes due to differential flexing.. After upgrading to ADM rings I'm now able to take five and ten minute exposures.. Differential flexing is a problem any time you have a guide scope piggybacked to your main telescope.. I honestly was not expecting to have as much trouble with flexing as I have had.. Currently flexing is the limiting factor keeping me from taking longer exposures.. Unless you use a camera which uses a second imager to make guiding corrections using the same imaging telescope your setup will have some degree of flexing.. One simply has to minimize it as much as possible.. I have purchased a few filters that I feel are very important for astrophotography.. Because CCD imagers are sensitive in the IR range as well as the visible range, if not filtered, the images captured tend to not be of very good quality.. After all, you normally just want to capture the visible light not the  ...   built my own dew heaters for both the main imaging scope and guide scope.. On the above photo the dew heaters are the two yellow straps seen on the telescopes.. I use a temperature controller board which I built as a kit to control the heaters.. You can get these on line for less than twenty dollars.. Dew heaters can also be purchased of course.. I found them to be rather expensive though and this is a project that most hobbyists can do themselves.. I followed the.. instructions on this post at iceinspace.. to build the heaters.. The weight of my complete telescope setup is over one hundred pounds.. This is not the type of setup that you want to be taking outside for an imaging session and then bring back inside every time if you can help it.. I had no intentions of doing this so from the start I planned for a semi permanent installation.. To this end I poured a cement slab for the Atlas mount to sit on.. I added a cable which secures the mount to the cement slab to keep the mount from ever tipping in high winds.. On the image to the right the cable is just visible in the center of the tripod legs.. I then purchased a large 365 cover from.. Telegizmos.. These covers are excellent and they will not leak, guaranteed.. The only thing to worry about is humidity inside the cover.. A simple solution is to add a heating rod inside the cover to keep the temperature above the dew point.. I purchased mine from.. ScopeStuff.. Still rust on bolts is an issue so I keep a close eye on this and regularly cover all needy parts with a thin film of grease.. My imaging cameras consist of a Meade DSI Color and Meade DSI Pro monochrome CCD camera.. These are good camera and work well, but they are older models and the imagers are small.. I use the DSI Color as the main imaging camera because it is easier to create full color images with it.. The DSI Pro requires the use of color filters to create color images and this can be time consuming so I use it as my guide camera.. One added benefit of using the DSI Pro for the guiding camera is that it is more sensitive than the DSI Color and this is beneficial when you are running 1 second exposures in the guiding software!.. Well, this is my primary astrophotography setup.. Rather simple yet quite effective..

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  • Title: Collimating your Newtonian Reflector
    Descriptive info: Collimation.. How to Collimate your Newtonian Reflector.. What is collimation anyway? Simply put collimation is the process of aligning the focuser, secondary, and primary mirrors (lenses, mirrors, prisms, eyepieces) in their proper positions.. For a Newtonian reflector telescope to achieve crisp and well focused views of planets and other heavenly bodies all of the mentioned components have to be accurately aligned with each other.. View Down Focus Tube.. For a beginner this can be no small task.. There are many websites on the Internet that explain step by step how to collimate your telescope.. One that I found to be very helpful was.. FAQ about Collimating a Newtonian telescope.. by Nils Olof Carlin.. This site goes into detail concerning the different sorts of errors that occur when any one of the above mentioned components is misaligned.. Most of the material in the site went over my head, but I was able to understand the steps needed for collimating my own telescope.. This is a picture of what you will see when looking down the focus tube of your telescope.. Now, one very important tool which you will absolutely need is a peephole.. Relax, you can make one out of a 35mm canister.. You will need to cut out the bottom of the canister and drill a hole about 2-5mm in diameter in the exact center of the canisters cap.. To the right is a picture of the peephole I use.. The canister is just the correct diameter and will fit nicely into the focus tube.. The purpose of the peephole is to ensure that you are looking directly down the center of the focus tube (this is very important).. Peephole.. Looking down the focus tube with the peephole in place you will be able to see the following; the focus tube, the secondary mirror along with the secondary mirror holder and clip, the reflection of the main mirror, the spider vanes, and finally the reflection of the secondary mirror.. At this point what you are looking for is that the secondary mirror is perfectly centered underneath the focus tube.. Don't worry about what or what you can't see on the secondary mirror at this point, just concentrate on ensuring that the actual secondary mirror is physically centered in respect to the focus tube.. If the secondary mirror is off to the left or right of center you will need to adjust the spider vane screws on the outside of the telescope tube to bring the mirror assembly back to center.. Be sure to unscrew one vane screw while screwing in the other.. If the secondary mirror is too far in or out of the tube you will need to loosen the set screws on the secondary mirror assembly (usually three) and then either screw in or out the center screw which holds the secondary mirror in place.. This process should bring the secondary mirror directly underneath the focus tube.. I like to rack the focuser in to the point where the secondary mirror just covers the focus tube opening.. In this way you will be able to make fine adjustments until everything looks symmetric.. The focus tube itself could be badly misaligned and might need to be centered, although this was not the case with my telescope.. Just check the focus tube to be sure it isn't grossly out of place.. If you are having a hard time seeing the sides of the secondary mirror for making the fine adjustments here is a trick that has helped me.. Take two different colored pieces of paper.. I used cardstock as it is not so flimsy.. Cut a piece and slide it behind the secondary mirror along the OTA so it sits directly behind your field of view when looking down the focuser.. Now cut a different colored piece and stand it up between the secondary and primary mirror so it is blocking your view of the primary mirror.. Now point the OTA at a bright source of light.. Now when you look down the focuser you will see the bright colors outlining the secondary mirror making fine adjustments easier.. The Spider Assembly.. The next step is to center the main mirror's reflection on the secondary mirror.. To accomplish this you will turn your attention to the  ...   main mirror with the center spot is put back in place on the telescope you can use the peephole as a rudimentary Cheshire.. Basically, what you want to do is take a flashlight and shine it over the peephole which in my case is somewhat transparent.. If you look down the peephole you should see the center spot on the main mirror, and a ring of light around it due to the flashlight shining through the peephole.. Most likely the center spot will not be in the center of the peephole, so adjustment to the main mirror will be necessary.. Main Mirror Set Screws.. The main mirror assembly normally has three set screws and three lock screws.. Unscrew the lock screws a bit, and then screw in or out one set screw at a time until you get an idea of what each screw does with respect to the center spot.. The goal is to adjust the set screws until the center spot is perfectly centered within the peephole.. In my case the paper reinforcement ring is just smaller than the peephole, so when the flash light shines down the peephole I can adjust the main mirror until I end up with a perfectly spaced light ring round the center spot.. At this point your telescope should be collimated.. The ultimate test is to point the telescope at a distant star using an eyepiece one to two times the power of your aperture value.. Be sure that the star is perfectly centered in the eyepiece and then rack the focuser in and out of focus.. When the star is out of focus you should be able to see the shadow of the secondary assembly and the spider vanes.. The shadow of the secondary assembly should be centered within the light circle created by the star.. If it's not, you will need to adjust the main mirror set screws in the direction of the dissymmetry.. The adjustments needed at this point will be very minute so be careful not to over do them.. Laser Collimator.. It is possible to use a laser collimator to assist in the collimation of the primary mirror.. I purchased an inexpensive one online and it has worked very well for me so far.. I want to stress that you should only use a laser collimator for adjusting the primary mirror NOT the secondary mirror.. In my experience using a laser collimator for adjusting the secondary mirror is a complete waste of time as it is very difficult to place the laser in just the correct location on the focuser to achieve good alignment of the secondary.. Use the visual approach to aligning the secondary.. The trick to good primary collimation using a laser collimator is to use a Barlow lens in conjunction with it.. I have taken an image of my laser collimator and Barlow lens combo.. The purpose of the Barlow is to defuse the laser light source from a point of light to a more broad light beam.. This light beam will be larger than the center spot on your primary and in turn will generate a shadow when the light is reflected back onto the target on the laser collimator.. This round shadow is what you will use to perfectly center on the laser collimators target by adjusting the set screws on the primary mirror.. I was amazed at how well this technique worked when I first tried it! I found this trick while searching on YouTube and it really does works.. Collimating your telescope doesn't have to be a nightmare.. In the process of collimating my telescope I learned how it was designed, how to take it apart, and how to put it back together.. Frankly, I feel much more comfortable working with my telescope now.. At first I did not feel comfortable at all with taking the main mirror out and putting a center spot on it, or taking the spider assembly apart.. Nevertheless, I had to do these things to correctly collimate the telescope, and I am glad now that I mustered up enough courage to take the thing apart and get the job done.. The crisp, well focused images which I am now getting from my telescope makes all of this hard work worthwhile..

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  • Title: Drift Alignment of an Equatorial Mount
    Descriptive info: Drift aligning an equatorial mount.. Polar aligning an equatorial mount for astrophotography purposes is not as easy as just pointing the mount to Polaris and commencing an imaging session.. For astrophotography purposes good polar alignment is absolutely necessary! The effects of bad polar alignment are field.. Using R.. ecticle.. Feature.. rotation and images that seem to drift right out of the field of view of your cameras.. Both are very frustrating and very easy to experience if one hasn't spent the time performing an adequate job of aligning the mount.. There are different ways of going about the alignment process, but my favorite is the drift alignment method.. I have found that after one gets the hang of it, this method is extremely accurate and one can actually see how well the mount is aligned in real time.. Any and all errors are clearly visible right on your computer screen.. I perform drift alignment with my CCD camera in prime focus, and use K3CCDTools3 and its reticule feature for monitoring the drift of the mount.. I learned how to drift align my mount from a post by Charlie Hein in the.. cloudynights forum.. I could try to regurgitate what I read there, but I rather quote his post in it's entirety as his explanation of drift alignment is so spot on.. Here it is:.. Lawrie, drift alignment really isn't anywhere near as hard as it sounds (although it does sound pretty daunting) - I avoided learning how to do it for way too long myself for that very reason.. Understanding what you're trying to do is key.. Hopefully, I can explain it in a simple to understand way.. In fact, I may over simplify for you just because I don't have any idea what your experience level may be.. Because of this, please don't think I'm talking down to you if my explanations seem too simplistic.. I just want to make sure that I present this in an easy to understand way.. On the other hand, please feel free to point out any portion of the following that you don't pick up on, and I will do my very best to clarify it for you.. That said, let's get started.. I'm not sure what kind of mount that you have, but I'm going to step out and make a guess that you do not have a fork mount on an equatorial wedge, but rather you have a GEM (like a CG5, SkyViewPro, LXD-55 or 75, or a similar mount).. If this isn't the case then let me know, although it really does not change things too much.. It's important to note that while it's not exactly essential to do a rough polar alignment on your mount, it will save you a *lot* of time in the process, because the closer you are to being right on, the less you have to move your mount around to get it right on.. Just guessing about where North is and how high Polaris is may put you farther out of alignment than the mechanics of your mount can compensate for, which would force you to physically move the mount in order to get it in the zone.. This would be very painful to discover 15 minutes or even longer into the process, so I would *strongly* recommend that you at least level your mount and sight Polaris through the polar scope (or the hole where one would go) before getting started.. It will save you a *lot* of time from here on out!.. Alignment Controls.. If you can't see Polaris, then point the mount due North, and set your latitude as closely as you can.. This is far from being an accurate way to do it, but it's better than just guessing.. Also, try to make sure at this point that your East - West (right-left) adjustment bolts (on either side of the mount as opposed to the front and back of the mount, which adjust up and down) are set so that there's plenty of travel in both directions - it would be very painful to find out that you couldn't move the mount more in a direction because you started out too far to one side or the other! I say this because the farther you are out of perfect alignment, the more travel you may need to get there, so it really pays to keep this in mind.. While we're talking about how you're setting up, let's also touch on where you're setting up - you need to have a clear view straight over your head and to the south (behind the mount), and you also need to have a view either to the East or West that is as low to the horizon as you can get it for the drift alignment to  ...   are, the star may start to drift immediately.. You can make adjustments as soon as you can positively detect the direction it's drifting in, using the above rules.. At first, you will probably want to make a fairly large correction.. Watch that you do not lose your driftng star off the edge of the screen while making your adjustments - if it looks like that is going to happen then center the star and then continue to move the mount if you need to.. As you get closer to nailing the alignment, make smaller and smaller moves.. I find that sometimes it's advisable to adjust past where you think the perfect point is so that you get a sense of what you are accomplishing by moving the scope.. The bottom line here is that you are aiming for having the star stay perfectly bisected by the East-West line of your recticle for a longer period of time than you would want to expose for without guiding - a good time frame is five minutes with no drift - the longer it can stay right on the line the better your alignment is.. I've had the star stay perfectly bisected for over a half hour (I lose track of time chatting with folks while it drifts), which is a very good alignment.. Now that you have drifted out the East West misalignment, you need to do the same for the North-South axis.. Leaving your DEC axis exactly where it is, unlock your RA axis and move it either to the East or West, whichever direction gets you closest to the horizon.. Find a star in the general vicinity, just like you did earlier.. Your camera should still be focused and correctly oriented, so all you need to do at this point is figure out where North-South and East-West are again, using the same trick you used earlier.. Once that's settled, you're ready to go.. Once again, bisect the star on the East-West line of the recticle, and watch for drift in the North-South direction.. However, this time we're checking to see if the mount is too high or too low, and we use the adjustments at the front and rear of the mount to move the mount up or down.. An added wrinkle here is that the rules are different depending on if you are looking at the Eastern horizon or the Western horizon:.. Step 2a - Correcting North-South misalignment (using Eastern horizon).. If the star drifts South, the polar axis is pointing too low.. If the star drifts North, the polar axis is pointing too high.. Step 2b - Correcting North-South misalignment (using Western horizon).. If the star drifts South, the polar axis is pointing too high.. If the star drifts North, the polar axis is pointing too low.. As before, we're looking to keep the star bisected on the East-West line for as long as we can stand to watch it - at least five minutes is a good rule of thumb, longer is always better.. Once you have this down, you might want to go back to check the East-West just in case you accidentally messed something up along the line - that's your call.. And that's that!.. No question about it - this procedure takes time - time to learn (repetition and familiarity make it faster), and time to perform (repetition and familiarity make it faster).. It taxes your patience, but it is definitely worth the trouble!.. Charlie.. Effects of Bad Alignment.. I had no clue on how to properly align my equatorial mount until I read the above explanation by Charlie.. I now keep a print out of the directions on me every time I go out to image.. The picture to the right is a perfect example of how an image will look like if your equatorial mount is poorly aligned.. The night I took this image I was in a hurry to align the mount so I could get going imaging M51.. Can you blame me? You will probably have to click on the picture to enlarge it, but in it you will see streaks that go from top right to bottom left as well as stars that look elongated.. These streaks are actually hot pixels which decided to make there presence felt between my regular dark frame acquisition sessions which I do between light imaging session.. Actually, this image was one of the reasons why I decided to.. Peltier cool.. my DSI Pro!.. At any rate, the downward direction of the streaks shows that my mount was poorly aligned.. I hope that the information here will help some out there as much as it has helped me.. Drift alignment of your equatorial mount is an important concept to master as an astrophotographer.. Good luck and clear skies..

    Original link path: /drift_alignment.html
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  • Title: Using SLR Lenses for Astrophotography
    Descriptive info: Astrophotography with SLRs.. Using SLR Lenses for Astrophotography.. Contrary to what one might think, the use of SLR lenses for astrophotography is very popular.. Telescopes with their long focal lengths and large apertures give great high magnification views of heavenly objects.. This is very desirable when imaging small planetary objects like Jupiter or Saturn.. What happens though when you attempt to image a deep space object like the Orion nebula which is 1,500 light-years away and.. M42 through Telescope.. around 15 light-years across with a telescope and a ccd camera at prime focus.. Well, if you're using a telescope like mine you end up with an image like the one on the left.. Not a bad image, but a lot of the nebula is being cut off due to the restrictive field of view.. This is how the nebula looks even after using a x.. 5 focal length reducer to try to alleviate the problem.. Inserting a focal length reducer in front of the camera has the effect of reducing the telescopes magnification power and hence giving you a larger field of view.. Nevertheless, if the goal is to capture the entire nebula and the space surrounding it, it's obvious that the telescope/focal reducer approach is not going to work.. Here is where SLR lenses come into the game.. By simply attaching an SLR lens to the ccd camera and then mounting the camera and SLR lens to the telescope in a piggyback fashion one is able to achieve truly wide field of view imagery.. M42 through 135mm lens.. To the right is an example of what using a 135mm SLR lens attached to a ccd camera can achieve.. This is a big difference isn't it? If you want even wider fields of view it is possible to use 55mm lenses or even 22mm lenses.. In all reality there is no limit to what sort of lens one can use.. It all depends on the object being imaged and what it is you are trying to accomplish.. One point which I feel is very important to point out is the fact that some SLR lenses can introduce.. comatic aberration or coma.. into images.. Coma is very easy to detect as it makes its presence felt as stars that look like comets around the edges of your images.. This is not a pretty sight and should be avoided at all cost.. Surprisingly, the solution to this problem is easier than one might think.. It's possible to suppress coma to a large extent by adjusting the aperture of an SLR lens.. Most SLR lenses have a dial which allows this adjustment of the aperture.. Normally you will see it labeled with numbers such as 2.. 8, 4, 5.. 6 up to 16 or 22.. These numbers are the f-ratios of the lens when stopped down to these smaller aperture openings.. For example, if you have a 135mm focal length lens, and your f-ratio is 2.. 8; then your lenses aperture is around 48mm.. On the other hand if you adjust the dial until it reads 5.. 6; then your lenses aperture becomes 24mm.. An adjustment of two clicks towards a more  ...   camera so high above the telescope is that more counter weight will be required.. I use the.. Mogg Meade DSI SLR adapters.. for attaching the SLR lenses to my DSI cameras.. These adapters are of great quality and I recommend them.. The Galactic Center.. I recently did some experiments using my Fujica ST-701 35mm film camera and wide angle lenses.. My goal was to image large portions of the Milky Way.. I have long wanted to achieve breath taking shots of the Milky Way like the ones I have seen on the Internet.. I knew this to be possible as most of the ones I have seen are from amateur astronomers like myself.. So I set out to see if I could succeed in this endeavor.. I used my equatorial mount which is now atop my.. homemade pillar.. I attached the film camera to the mount in the same way as I attach my ccd cameras.. I used my 28mm Avitar wide angle lens.. I pointed the camera towards the galactic center which was a bit low in the Western horizon and took a number of exposures ranging from 2 minutes to 5 minutes.. I used 800 ISO FujiColor Superia, and had it developed at the local WalGreens.. I asked for the pictures to also be put into a CD for easier post processing of the images.. Without any post processing the images looked washed out due to light pollution and vignetting.. I used PixInsightLE and the.. DynamicBackgroundExtraction.. process to salvage the best images.. To the right is one such image.. This is actually three 5 minute exposures of the galactic center of the Milky Way stacked in Registax4 before putting the image through PixInsightLE.. The galactic center is to the right and slightly below Jupiter (the bright object left center).. In this image M8, M24, M17 and M16 are all visible.. As can be seen, the use of 35mm film and a wide angle lens does allow for true wide angle capabilities.. I can't achieve this level of visibility with my CCD imagers.. Using 35mm cameras in this way minimizes the issues of poor tracking and alignment of your equatorial mount which is such a killer when it comes to film.. I didn't start to see star trails until I exceeded 15 minutes in my exposure times.. Even then, I know I can go over this limit so long as the motor is tightly attached, and the mount well aligned.. I have taken images of other portions of the Milky Way as well with more to come! They can be viewed in the gallery.. The addition of different focal length SLR lenses to your astrophotography arsenal is indispensable.. These lenses give you the flexibility to photograph many more objects in the sky.. If you're going to photograph the Ring nebula or a planet you will probably need to use your telescope.. If you want to get a full shot of the Moon or photograph the Horsehead and Flame nebula region all at once, a 135mm SLR lens will do the job nicely.. Again, experimentation is going to be your best friend here, so get out there and start experimenting..

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  • Title: Peltier Cooling the Meade DSI Pro
    Descriptive info: Peltier Cooling the Meade DSI Pro.. The reason for me taking on the challenge of attaching a cooler to my Meade DSI Pro is simple.. The camera is a bit noisy.. I'm not taking anything away from the Meade DSI Pro, it is a very sensitive camera and I am ninety-nine percent satisfied with how it performs.. I simply began to notice.. Peltier Cooler on DSI Pro.. that during imaging sessions, if I waited to long between taking darks and taking light images, new hot pixels would appear and cause problems in my captures.. I tried using a fan to cool the camera, but this did not sufficiently correct the problem.. I then decided to go with my next option, Peltier cooling of the camera.. The Meade DSI Pro has a large heat sink with a cold finger on the inside which makes direct contact with the ICX254AL CCD chip.. I figured this was a good thing as it shouldn't be too difficult to attach a cooler to the heat sink, and have the chip be cooled by the cooler via the cold finger.. The only problem is that the heat sink on the DSI is rounded and not flat.. I thought about just using putty to fill the empty space around the heat sink prongs, but I wanted something more efficient than this.. I decided to use my Dremel tool and grind off a total of 42 heat sink prongs to allow the Peltier to lay flat on the surface of the case.. This is a very intrusive approach and might not be for everyone.. I know, because I had a very hard time convincing myself to doing it.. It won't hurt the camera in any way though, so long as you have taken the heat sink off the camera first! Nevertheless, proceed at your own risk.. I used a 40mmX40mm 4mm thick Peltier which I purchased from.. QualityKits.. A Peltier this size fits nicely in an opening similar to the one I created on the DSI heat sink.. I then took a CPU heat sink and fan from an old Celeron computer and placed it on top of the DSI heat sink to see how well it fit.. I had to slightly grind a few rows of prongs to allow for the CPU heat sink to fit snugly over the Peltier.. But once done I had a very good contact between the DSI case, Peltier, and CPU heat sink.. I used a silicone based heat sink paste between all the surfaces.. I also purchased a small kitchen temperature probe.. I took it apart and placed the sensor on the actual cold finger of the DSI heat sink.. I then ran the small wires out between the two halves of the cases ,and placed the LCD temperature gage on the side of the DSI.. Placing the temperature sensor on the cold finger should yield very accurate temperature readings.. Another important part of this design is the power supply.. Powering the Peltier cooler is straight forward.. A good 12 Volt DC source which is able to supply a few amps should be sufficient.. A variable power supply is even better.. In my case I am using a homemade variable power supply with a 3 Amp transformer.. I added a 4 Ohm 70Watt power resistor  ...   in Florida during the summer months.. The dew point and consequent condensation of the imaging chip is a real limiting facture to how low you can go unless you take more elaborate actions like enclosing the CCD chip in an air tight chamber with all the humidity pumped out of the chamber.. This is far beyond what I'm willing to do, and at any rate, I'm totally satisfied with the results I have achieved thus far.. BS2e Peltier Cooler Controller.. After some time of using the Peltier cooler on the Meade DSI cameras I came to realize that a controller was in order.. The problem I was seeing was two fold.. Firstly, I was having to adjust the power to the cooler way to much in an attempt to keep the temperature above dew point during imaging sessions.. Secondly, the variations in temperature generated by me fiddling with the power supply were causing problems with my dark frames.. There were hot pixels which I could not correct by dark frame subtraction because of the wild variations in temperature.. BS2e Cooler Controller.. I decided to build a microcontroller based around the BS2e by Parallax to solve the problem.. I chose this microcontroller because I had one laying around doing nothing.. The Basic Stamp line by Parallax is for the beginner in the world of microcontrollers.. The language has some limitations that can make life a bit difficult at times.. Nevertheless, the BS2 is a capable microcontroller.. I used the Parallax.. Super Carrier Board.. for the build.. This board provides a nice area for soldering additional components.. On the prototyping section of the board I installed an.. SHT11.. temperature/humidity sensor, an IRL3103 MOSFET switch circuit for turning the cooler on and off and an RC circuit used by the.. AD592.. temperature probe which is attached to the cold finger inside the DSI camera.. I added an LCD screen to the board to be able to quickly get readings while outside.. From within the house I use the serial console to read the values.. The board is powered by a 12 volt power supply.. The most difficult part of this project was coding the Basic Stamp due to it's math limitations.. The dew point portion of the code was particularly difficult and.. I couldn't have done it without help from this site.. Here is the.. BS2 cooler controller.. source code.. for anyone wanting to give this a try.. And here it is in.. plain text for a quick look over.. There are a million different ways to build one of these peltier cooler controllers starting with what microcontroller one uses to hardware to software.. I decided to post my experience with building one in the hopes that it helps point someone in the right direction.. This project took me a number of weeks to build and there were quite a few instances when I thought I would never be able to complete it successfully.. But the satisfaction I now get every night I use the telescope knowing that I don't have to worry about the CCD fogging up as well as just seeing the temperature track the due point so effortlessly makes it all worthwhile.. Well, I hope the information here will come in handy and if you have any questions just send me an email.. Good luck!..

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  • Title: Radio Telescope
    Descriptive info: Radio Astronomy.. Radio Astronomy Telescope Project.. Radio astronomy is a relatively young field.. At least when compared to optical astronomy anyway.. Some of the early names in this field are Karl Jansky, and.. Grote Reber.. These men made their great discoveries during the 30's and 40's.. Grote Reber for example discovered that contrary to the theory of thermal radiation, radio signals coming from outer space were weaker at higher frequencies.. The theory that explains this is.. synchrotron radiation.. This is good news for the amateur astronomer as lower frequency radio equipment is usually easer to work with than higher frequency radio equipment.. Synchrotron radiation is particularly strong in the frequency range between 38MHz and 700MHz.. There are a number of recognized radio astronomy quiet frequency in this range as well so this is also good news.. Cassiopeia A in Radio.. I have always been interested with anything radio.. So naturally, trying my hand at radio astronomy is something I've wanted to attempt for some time now.. I have to admit that this project was full of difficulties and disappointments.. Nevertheless, after months of on and off attempts at trying to get my radio telescope working I think I finally have a working unit.. When it comes to a radio telescope the components used are a directional antenna or dish antenna, a sensitive receiver, and a recording device.. Dish antennas are normally used more because they remain effective over large frequency ranges.. This is important when one is trying to monitor many frequencies instead of just one.. With this said, I came across a great website which sells some of the components needed to build a radio astronomy telescope.. The website is.. MTM Scientific.. , and I purchased the CATV tuner and 10 element Yagi from this website.. The CATV tuner is used to tune into 611MHz which is a recognized.. radio astronomy quiet frequency.. The 10 element Yagi is tuned for this 611MHz frequency as well.. I'm using a.. DI-194RS.. analog-to-digital converter attached to a PC for the recording device.. I have had a lot of trouble getting the CATV tuner to produce a signal on its IF output pin.. The IF pin is used as the signal output from the CATV tuner which is then AM demodulated using a 1N34A germanium diode and DC amplified using a INA122 instrumentation amplifier.. The amplified DC signal is then fed into a recorder.. This is the standard configuration for a basic radio telescope.. For whatever reason though, I can not get a strong enough signal from the IF pin when tuned to a TV station on channel 38 which is just above 611MHz (Ch 37).. On the other hand I can get a perfect IF signal from the CATV tuner when tuned to a lower frequency like say a station on the FM radio band.. I really have  ...   results.. My goal for this project was to detect.. Cassiopeia A.. Cassiopeia A is the strongest radio source aside from the Sun in the sky and is about 11,000 light years from Earth.. What's funny about this supernova remnant is that it is very hard to see visually.. Only very long exposures can make this nebula out yet it is incredibly bright in the radio spectrum! Here is one of my first successful recordings of Cassiopeia A.. It was taken on November the 15th, 2008.. The hump in the middle of the plot with the marker is Cassiopeia A.. For these recordings the antenna is positioned at different points on the meridian depending on what object is being observed.. The telescope then drift scans that region of the sky.. Here's a two day plot of Cassiopeia A with the second day superimposed over the first.. The marker is marking the transit of Cassiopeia A for the first day, 20:04 local time 11/16/08.. On the second day Cassiopeia A transited about four minutes earlier.. For this recording I placed a 1200uF capacitor across the output of the CATV tuner to smooth out the plot some.. This radio astronomy project has been a real challenge for me to get working correctly.. All my troubles have centered around the IF output of the CATV tuner.. I have so far not been able to get the IF pin to work correctly even after trying two different tuners.. Therefore, I don't know if I have had the bad luck of getting two defective tuners or if there is more to the IF issue.. Working CATV RA Scope.. What matters is that the tuner is working ok using the AFT pin so not all is lost.. I would like to try detecting some more object in the future.. I would like to try my hand at Sagittarius A and Cygnus A.. These two objects are the other heavy hitters in the radio spectrum and I think my receiver might be sensitive enough to detect them.. It might also be possible to detect pulsars although I'm not holding my breath on this one.. The image to the right is of the CATV tuner receiver with the three voltage (5V, 12V, 30V) board under testing.. I plan on inclosing the receiver in a steel cage for shielding because it tends to detect body movements near its vicinity.. After all, these tuners are always shielded when inside TVs and VCRs.. I hope the information in this page might be helpful to others having the same type of trouble as I am with this CATV tuner.. Or maybe it might inspire someone to give this project a try.. Bottom line, this project has been a great learning experience for me, so although I had all kinds of problems I'm glad I kept at it!.. Good luck!..

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  • Title: The Earth-Ionosphere cavity resonance
    Descriptive info: Detecting the Earth-Ionosphere Cavity Resonance.. It's probably not a surprise to many that I'm interested not only in astronomy, but also electronics and radio communications.. I hold a general class Amateur Radio license with call sign W4GON.. I have been tinkering with radios since I was twelve years old.. So in other words, I'm not only interested in what I can see in the sky but also what I can hear!.. The following is an attempt to document my personal experience with the reception of the Earth-ionosphere cavity resonances or simply the Schumann Resonances.. They where named after the German physicist W.. O.. Schumann who predicted their existence and later discovered them.. Schumann Resonance.. The Schumann Resonances are located in the ELF (Extremely Low Frequency) and SLF (Super Low Frequency) range of the EM spectrum.. This range is from 3Hz - 30Hz and 30Hz - 300Hz respectively, very low indeed.. The surface of the earth and the ionosphere create a spherical cavity that just like a tuning fork has a resonant frequency.. This is the heart beat of our planet and these resonances are naturally exited by the thousands of lightning strikes occurring every second around the planet.. High altitude nuclear bomb detonations also artificially excite these resonances to high levels for short periods of time.. This is how the resonances were first physically detected.. Experimenting equipment detected them during high altitude nuclear burst testing in the 50s.. If one takes the speed of light in kilometers (300,000 Kms) and divides it by the circumference of our planet in kilometers (40,000 Kms) one ends up with 7.. This number is in cycles per second so one could predict that the base resonant frequency is near 7.. 5Hz.. It is interesting to note that our Alpha brain waves fall right around this base frequency.. I was very interested in trying to detect these resonances with a receiver.. I thought it would be an accomplishment to make a receiver sensitive enough to detect these very weak signals.. More importantly though, if I could detect these signals then I could also detect other signals of natural and or man made origin in this range as well.. HAARP.. operates in this frequency range, testing among other things new.. ELF submarine communication.. techniques.. It turned out that for reception of this frequency range the receiver was right in front of me.. A computer and a sound card with its DSP capabilities make a great low frequency receiver.. The only parts that were missing were the antenna, the preamplifier and the spectrum software.. I needed some help with this part so I went to Renato Romero IK1QFK's web site.. Radio Waves below 22 Khz.. This site is very comprehensive so take your time.. I downloaded Spectrum Laboratory, the spectrum software from.. DL4YHF's Amateur Radio Software.. This program is feature full and best of all it's free.. It is not new user friendly so read.. FFT for dummies.. at Renato's site if all this stuff is kind of new to you.. I decided that a long wire antenna of about three hundred feet was the most practical setup for my location.. I also decided to go with the following preamplifier from Renato's web site.. I had to order the OP07 and the positive and negative voltage regulators for the dual polarity power supply from.. Digi-Key.. The rest I either had or bought from Radio Shack.. Testing the ELF Receiver.. When I started the project I didn't have all the power supply parts or the OP07.. I did have some 12 volt batteries and a few OP27's though.. I used an OP27 and wired two 12 volt batteries in series to supply the dual polarity needed by the op amp.. I also put a variable resistor in place of R3 with a 10 ohm resistor in series for variable gain.. After blowing out 3 transistors because I had them backwards I finally got the circuit working (I always do that).. I connected the long wire antenna via coax to the preamplifier and a shielded audio cable from the preamplifier output to the line input of the sound card.. I immediately noticed that the preamplifier was overdriving the sound card with the 60Hz mains signal.. It did not matter whether I lowered the op amp gain to one and or lowered the sound cards line-input volume to zero.. I went back to Renato's site and read.. Reception of Schumann Resonance.. I discovered that a low-pass filter is absolutely necessary if you want to detect anything weaker than the hundreds of thousands of volts flowing through our power grid.. So I followed his directions and put a simple RC low-pass filter in series with the long wire antenna.. I had to play a bit with the capacitances, in particular with the bypass capacitor value but the low-pass filter solved the overload problem.. I was able to increase the preamplifiers gain to around 10 and the sound card volume without any overdriving.. Below is 80 minutes worth of the E-field frequency range from 0Hz - 100Hz received with the above setup.. Both top and bottom channels in the above spectrogram are from the same signal.. I simply put a software low-pass filter on the top channel to get rid of the 60 Hz signal that can be seen on the bottom channel.. Five resonances can be seen at around 7.. 8Hz, 14Hz, 20Hz, 26Hz and 31Hz.. The times between 2000 and 2200  ...   sprites.. This is a work in progress.. All the above spectrograms are of the Schumann background or the quasi-permanent SR field oscillations.. Modes above 40Hz are usually very difficult to see as they are buried in the Schumann background spectra, because the corresponding wavelength is generally several thousand km and multiple sources are non-coherent at this spatial scale (.. Every so often though spatially isolated gigantic discharges can excite the Earth-ionosphere resonator in such a strong manner that the higher modes can be distinguished in spectra obtained from short time series (a few seconds).. Below is an example of a Q-burst taken at my location.. The frequency range is from 0Hz to 120Hz and the time period is about two seconds (time is EST).. This Q-burst was captured with a new and much improved ELF receiver which I installed with the help of Brian Miller at.. Electricterra.. Here is an image of the new setup.. with a spectrogram showing the first seven SR modes.. Many Q-bursts are characterized by a double-spike like pattern and their amplitudes exceed in most cases the average Schumann background by a factor of 10 to 20.. It's the huge size of these discharges that allow the higher modes of the SR to be observed in short time series spectra.. Below is the frequency domain plot for the same above Q-burst.. The first seven modes are clearly visible before the analog 60Hz notch filter begins to take over.. On the upper side of the notch filter numerous higher modes which usually are non-existent become clearly visible.. The leading bipolar spike in the double-spike pattern of Q-bursts (time domain example above) is caused by the lightning discharge directly.. The second spike is actually the around the world signal as it reaches the receiver! This delayed spike is usually slightly attenuated and widened in time due to dispersion.. The time interval between the two spikes is in the order of 130-160ms and corresponds to the wave front travel time for one Earth orbit.. Research has shown that there is a strong link between sprite generating lightning and Q-bursts.. On the evening of March 26th, 2010 I was able to image a number of sprites over the Gulf of Mexico which exhibited strong ELF transients.. Here is an example of one such sprite.. There were clouds in the field of view hence the fuzzy sprite.. The above sprite was caused by a strong lightning which generated a Q-burst that was captured by the ELF receiver.. In the below plot the sprite generating Q-burst is the second larger transient.. The characteristic double spike pattern of many Q-bursts can be seen in this transient and is labeled Double Spike.. The delay between the first and second spike here is around 160ms.. Not all sprite generating Q-bursts possess this double spike pattern.. From my observations about half of all sprite generating Q-bursts show the double spike pattern.. Here is another example of a bright sprite caused by a Q-burst generating lightning captured on July 11, 2010.. This sprite was extremely bright and much detail can be seen within the sprite including bright tendrils and a diffused upper region.. This was pointing north over Georgia.. Here is the accompanying Q-burst for the above sprite.. As can be seen this transient is huge compared to the surrounding activity.. The double spike pattern is clearly seen in this Q-burst as well.. The delay between the first and second spike for this one is again around 160ms.. Damped oscillations after the initial spike and before the second spike are also visible.. This was clearly a bell ringer!.. I have forwarded some of these Q-burst double spike examples to a few academics and interest in them has been shown.. I was asked by them to create a histogram of delay times between the doublets (as they termed them).. Subsequently I began taking measurements for a two week period during March 2010 and below are the results.. This histogram consists of a little over one-thousand Q-burst samples.. Delay times run along the 'X' axis and Q-burst counts along the 'Y' axis.. The histogram shows three spikes ; a large one at around 150ms, a smaller one at around 130ms and a much smaller one at around 110ms.. I find these delay times intriguing! My interpretation of the delays is that the large spike at 150ms is from Q-bursts originating in the Amazon basin (for the most part).. The smaller at 130ms is from Q-bursts originating in Africa (the Congo region), and the smallest at 110ms is from Q-bursts originating in maritime south-east Asia.. If one thinks about this logically it sort of makes sense.. One would expect the largest delay times to be from nearby Q-bursts since the delay time between the first and second spike (round-the-world wave) would be longest with nearby Q-bursts.. I have evidence that this is indeed correct from actual sprite generating Q-bursts which I have imaged and recorded (example above).. I have yet to measure delay times below 155ms for sprite generating Q-bursts showing the double spike pattern.. One possible use for Q-bursts is as a proxy for global scale sprite detection.. The problem with this is that it has been shown that not all Q-bursts generate sprites, so obviously there are other factors at work in sprite generation.. Regardless, monitoring for Q-bursts is but one more fascinating aspect of Schumann resonance study.. Thanks for reading, and please email me if you have any questions..

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  • Title: Very Low Frequency Receiver
    Descriptive info: Natural Radio.. The Very Low Frequency (VLF) band is located in the frequency range between 3KHz and 30KHz.. This band has the unique characteristic of having a portion fall within the audio frequency range of our ears.. What's more, the bulk of a lightning strikes energy is deposited between 2KHz and 10KHz.. These two points form the basis for everything which follows.. So how does one go about building a VLF receiver anyway? You might be surprised to find out that it is not very difficult to build one.. In it's simplest form (and not so simple forms) a VLF receiver is nothing more than an audio amplifier attached to an antenna.. One of the most popular uses for a VLF receiver is for listening to lightning strikes from around the world, and the interesting effects that this activity has on our atmosphere.. The Source of Spherics.. The snap, crackle, and pop sounds from lightning activity which one can hear on a VLF receiver, or AM and short wave radio for that matter are called atmospherics or spherics for short.. These are the most common sounds heard on the VLF band and can be heard 24 hours a day.. Spherics show up as wide band bursts when plotted on a spectrogram.. This is because a lightning strike is not a narrow band event as is say a military VLF transmitter like.. NAA in Cutler Maine.. at 24KHz.. These types of wide band signals are characteristic of natural EMF activity from Earth as well as our solar system and beyond.. So it shouldn't surprise anyone that another name for this hobby is natural radio.. I have been interested in natural radio for a good ten years now.. Over the years I have built a number of VLF receivers of the E-field and loop antenna type.. As a matter of fact the Schumann resonance receiver which I use,.. , can easily be modified to receive the entire VLF band.. I'm currently using a homemade receiver for this project which I detail below.. Another option is the VLF-3 from the.. Inspire Project.. The Inspire Project is a NASA sponsored (among others) project involved with interactive NASA space physics ionosphere radio experiments.. They are doing very interesting stuff.. The.. VLF-3 kit.. which they provide is of very good quality and easy enough for just about anyone to build in a few quiet nights in the radio shack.. I recommend this receiver for anyone interested in getting into this hobby.. That is if you don't want to build your own receiver.. Ok, you might be asking yourself what's the big deal about popping sounds from lightning in the VLF band anyway.. Yes I agree, after a short while spherics can get very boring.. Thankfully, there is more to natural radio than just spherics.. During dusk, dawn and the intervening night hours the ionosphere goes through a transformation that has a profound effect on spheric activity.. At dusk the D layer (lowest layer) of the ionosphere fades away leaving the higher E and F layer only.. This is due to the lack of ionizing radiation from the Sun during the night hours.. This phenomena can easily be seen on a.. SID receiver plot.. as a sharp rise in the received signal strength of a monitored VLF transmitter at dusk and the subsequent signal drop at dawn.. During the daylight hours spherics can travel upwards of 2000 to 3000 kilometers from the source of the lightning strike.. These spherics reach the receiver via the wave guide created by the D layer and the Earth's surface.. At night though it's presumably the much higher E and F layers that are responsible for the sky wave component of a VLF signal.. This allows VLF signals to travel considerably further at night.. VLF Outdoor Enclosure.. During the night hours, spherics from much further than 2000 or 3000 kilometers can be heard! As a matter of fact during night hours it is possible to hear spherics from clear across the planet.. These types of spherics are called tweeks.. Tweeks get their name from the distinctive tweek sound they produce.. They can easily be distinguished from normal spherics just by their ringing sound alone.. On a spectrogram tweeks generate a small tail at around 2KHz and it's harmonics.. It is this tail that gives tweeks their unique sound.. Here's an example of a.. tweek with a very long tail.. captured with my setup.. Tweeks are spherics that have traveled for many thousands of kilometers through the Earth-ionosphere wave guide, and because of this they undergo dispersion.. Dispersion is the process of higher frequencies arriving at the receiver slightly faster than lower frequencies.. The lower frequencies only lag by a few hundredths of a second, but this is enough to change how a spheric sounds at great distances.. Dispersion is associated with the cut-off frequency of a wave guide.. All wave guides have a cut-off frequency and the Earth-ionosphere wave guide's cut-off frequency is around 1.. 7KHz.. This is why we see tweek tails at this base frequency range.. I say range because the Earth's wave guide varies with the reflecting height of the ionosphere.. There is a nice paper that goes into more detail about tweeks, dispersion and cut-off frequencies in the Earth-ionosphere wave guide with formulas and all, and it can be.. Dispersion plays a very important role in natural radio and there is another phenomena that takes dispersion to the extreme, whistlers.. Whistlers are less common than spherics and tweeks, but are truly worth the effort of detecting them.. Whistlers are associated with intense lightning strikes, and research has shown that they might be linked to upward electrical discharges from thunderstorm tops.. These types of lighting are a hot subject in the scientific community today, so VLF receivers are on the cutting edge of science! The theory goes (highly simplified) that energy from intense lightning strikes can get coupled into the magnetosphere through the ionosphere, and this energy then becomes trapped inside magnetic  ...   spheric or tweek which generates the whistler can also be seen.. For example the next spectrogram shows a tweek about half a second before the whistler.. The dispersion time of the whistler categorizes it as a one hop whistler meaning that you would expect to possibly see a tweek preceding it if propagation conditions are favorable.. Therefore, the tweek marked source originated in the South Pacific off the coast of Chile near the Arctic Circle, and it shows the dispersion one would expect to see for a spheric which has propagated via the Earth Ionosphere wave guide for thousands of kilometers.. Some of that same energy was ducted into the Magnetosphere and arrived at my location via a magnetic field line(s), and this signal shows dispersion consistent with this mode of propagation (whistler mode).. There's a bit of ambiguity as to which of the two tweeks in the above spectrogram caused the whistler (if either.. ).. In chapter 4 of.. Robert A.. Helliwell's.. book.. Whistlers and Related Ionospheric Phenomena.. , he details the steps used for identifying the sources of whistlers.. The first method and most used when available is to compare several whistlers in the same run.. If there are at least three whistlers to compare from the same run high reliability can be achieved just by using this method.. Fortunately I had a number of other whistlers from this same run which I superimposed on top of each other in Photo Shop.. I then aligned the whistlers and looked for causative impulses which aligned to within 1mm of each other.. You're looking for impulses within a second of the whistlers here (one hope whistler).. In the case of the above whistler, the strong tweek to the left of the marked source tweek was just outside of the threshold while the weaker marked tweek fell within the 1mm range called for in the book.. Therefore there is a good chance that the above marked tweek was the source of the whistler.. And here are three recordings of whistlers along with their spectrograms taken with my setup on March 18th 2009 (you might need to right click and then click on.. Save Target As.. ):.. Whistler one audio.. Spectrogram.. Whistler two audio.. Whistler three audio.. When hunting for whistlers one should look for strong lightning activity some hundreds of miles away from your location as well as near your magnetic conjugate point.. In the case of Florida, its conjugate point is off the coast of Chile.. The orange circle.. on this map.. roughly shows Florida's conjugate point.. Lightning activity near the receiver is important because these nearby storms can at times generate whistler echoes.. Here are a few examples of two hop echoes taken on the morning of May 23rd 2009.. On the second example there are actually four different echoes which can be heard.. (you might need to right click and then click on.. Two hop echo audio.. With two hop echoes the source spheric which causes the echo is normally always identifiable.. In the above case the source spheric is one of the strong strokes just before the echo.. With some practice one can predict which spherics will generate echoes! The dispersion times for one, two and subsequent whistler echoes depends on Latitude.. For example, whistlers in Florida will always sound shorter than say whistlers in the UK.. Regardless, single and echo whistlers can always be differentiated easily.. Here is a comparison.. of a short whistler and a two hop echo.. The dispersion time deference between the two is clearly evident.. Both of these examples where from the same run on the 23rd of May 2009.. Here are a few examples of rare whistler trains from Florida.. This activity was recorded during a strong geomagnetic storm on March 3rd 2012.. About twelve echoes can be counted on the spectrograms.. Whistler Train audio.. Natural radio activity usually increases during geomagnetic activity.. During solar storms whistler as well as.. chorus.. activity tends to increase greatly, particularly in the higher latitudes.. Therefore, one should also keep track of solar weather when hunting for whistlers and the like.. Spherics and the Earth-ionosphere Cavity Resonance.. I also operate an.. ELF receiver.. which I use to detect the earth-ionosphere cavity resonance or as it's better known, the Schumann resonance.. Spherics and the Schumann resonance are intimately related.. It is the hundred or so lightning strikes per second occurring around the globe which energize the earth-ionosphere cavity which in turn causes it to resonate like a tuning fork at it's base resonant frequency.. One can calculate the earth-ionosphere cavity resonance (highly simplified) by taking the speed of light (300,000 km) and dividing it by the circumference of the planet (40,000 km).. The result of the division is 7.. The actual base mode of the Schumann resonance is at around 7.. 8Hz give or take.. 3Hz.. Below is a spectrogram of the VLF range with a spectrogram slice of the ELF range superimposed showing the first three modes of the Schumann resonances.. They are the three ripples below the 20Hz marker.. The red lines point to where the Schumann resonance is located in relation to the towering wide band spheric activity.. I find it fascinating that something like spherics which sound like little inconspicuous pops and crackles on a VLF receiver are actually pumping tremendous amounts of energy into our atmosphere and causing our very biosphere to ring at it's resonant frequency.. Just think about this for a minute.. The fact that technology has reached a point that one can detect these phenomena with a simple electronic receiver, a computer and a soundcard is truly amazing.. It is possible to use.. to stream a live VLF stream so one can see the VLF sounds as well as hear them.. Instructions on how to accomplish this using Spectrum Lab can be.. My receiver along with a number of other natural radio receivers can be accessed here:.. http://abelian.. org/vlf/.. Have fun, and please email me if you have any questions or comments..

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