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Last updated: 2/05/10
Welcome to Midnight Sun Astrophotography. I started this site in order to document my progress and techniques, in this hobby and hopefully to be able to help out anyone else starting out in this field. Astrophotography is something that anyone with a camera and a tripod can get started in. Whether you have a film SLR, a DSLR, a point and shoot camera, or webcam, there are ways to utilize these to get some nice shots at night no matter where you are shooting from or how experienced you are in photography. If you have a desire to get out there and try your hand at it, that is half the battle. You don't need thousands of dollars in equipment to be able to get some great images of the night sky. And with the advent of digital cameras, you no longer need to spend tons of money buying and developing film only to find that your images were out of focus, or off target, or ruined by the processing lab. Now you can check all those things and simply delete a shot if it's not what you were looking for. The shot below of the crescent moon and Venus was taken early one morning, using a Canon 350D and a 300mm lens mounted on a tripod. The shot above was taken using the same 350D and an 18-55mm lens.
There are four ways to shoot astro photos with a traditional camera. Webcams will be covered separately. Afocally, Prime Focus, Tripod Mounted, or Piggybacked on a scope. Except for the Prime focus method, any camera can be used. Prime focus requires that your camera has a removable lens. It also requires alot of "back focus", which can be a problem with some scopes. It also allows photography at only one effective focal length, which is usually too short to do real justice to the scope's full ability to record lunar and planetary detail. With Afocal, both the eyepiece and camera lens are working at the optical image distances that they were designed for. Here, you are positioning the camera in front of the eyepiece and shooting through the scope's eyepiece. This can be done by simply holding the camera by hand up to the EP as close as possible and shooting. This method will work, but the results will be varied, and probably not great. You can buy a device which clamps the camera in front of the EP and is alot steadier than trying to hold it there. There are also adapters that will fit most cameras that can couple the camera to the EP and shots can be taken this way. Most point and shoot cameras also have a thread around the camera lens that is made to accept macro and telephoto lenses and this can be used for an eyepiece adapter as well. You can also position the camera on a separate tripod from the telescope. This will eliminate any vibrations being transferred from the camera to the scope when the shutter is opened.
After you have gotten familiar with the sky and your equipment with afocal and/or piggybacking, longer exposures using prime focus is the next step. With prime focus you simply remove the camera's lens and attach the camera to the focuser of the scope instead of an eyepiece. Sounds easy, right? Not exactly. You are now using the telescope as the camera's lens. Of course, you'll need an SLR with a removable lens. Now, polar alignment becomes more critical since any errors in alignment will be magnified resulting in mis-shapened or blurred stars or trailing. With longer exposures, guiding also comes into play. Fortunately, autoguiders now have made this aspect much easier on the photographer than in the past. Focusing also becomes a bit more of a challenge especially if you have a fast scope. Newtonians generally have low f/#'s and not much "back focus". Back focus is the distance inward beyond the camera's film, or image plane that the focuser must be racked in to get to focus. This is mainly a problem encountered with Newtonians. Other types of scopes, refractors, Cassegrains, Schmidt-Cassegrains and Maksutov-Cassegrains normally have plenty of back focus so that all you need is a T-ring for prime focus photography. With a Newtonian, you may need to find a low-profile adapter that will allow you to achieve focus. A lo-profile focuser itself may also be available that will work with a Newt. My Newtonian Is an f/4.9, and I used halves from two different adapters to get a low-profile adapter. One side was from an Olympus OM-1 ring that had threads that fit into the 2" focuser housing. The other side was from a T-ring for a Canon 350D, that mounts to the camera as a lens would. I unscrewed the two halves and epoxied them together. I have looked, and couldn't find an adapter that would do what this one does, without buying another focuser. I probably will get a lo-profile focuser before long just to make mounting and unmounting the camera quicker and easier. The only hassle with this setup is that the camera has to be screwed into the focuser, instead of being dropped in like an eyepiece. This means disconnecting the USB cable and AC adapter connected to the camera. Also, having to screw the camera into the focuser can throw off your framed shot or your autoguider which then has to all be set up again. Once screwed into the focuser, I only have about 1/4" of focus travel. But it does allow the camera to come to focus.
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In a tripod mounted setup, you merely need to set your camera up as you would for a daylight shot. With this method you can get some nice widefield constellation shots, the moon, sunsets, star trails, and lightning, which is one of my favorite subjects. If you are using a point and shoot camera, you may be limited to exposures of 1 minute or less. This is where stacking software comes in handy. Several short exposures can be "stacked" in order to produce some great images even with short exposure times. If you are using an SLR, you can experiment with different lenses and aperture values to see what works best with particular subjects.
The next step beyond a tripod setup is piggybacked. In order to track the stars without trailing, the camera needs to be mounted on an equatorial mount that is polar aligned and equipped with a clock drive. The most common method of doing this is to mount the camera on top of the scope using the mounting rings. The ring has a threaded hole on top, and can be used to mount the camera using the camera's tripod mounting hole. Other types of mounts use a strap that wraps around the optical tube with a mount for the camera on top. There are mounting bars that will place the camera to the side of the scope as well. You can really attach the camera in any way that it is secure and steady and won't affect the balance of the mount.
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| Location |
| Equipment |
| DSO's |
| Lunar |
| Planetary |
|Terrestial|
|Events|
| Software |
| A.P. Supplies |
| Thailand |
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Astrophotography
Prime Focus Photography
Another solution for the back focus issue with Newtonians is to move the primary mirror forward a little bit in the optical tube. But then, when using eyepieces, it may be necessary to use an extension tube to move them out to the new position of the image plane. This was something that I didn't want to get into, so for now, I am opting to go with my homemade lo-pro adapter.
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