reply to post by spacemanjupiter
You haven't lived until your eyebrows freeze onto your guidescope! As noted above, a T-ring is required, make sure it fits your scope and the
camera. I prefer an equatorial mount to a german mount and an extra heavy tripod. Your telescope must have tracking so that it moves at the rate the
sky moves. I use an 8-inch scope when I take photos. It collects a lot of light. The bigger the aperature, the better. These photos are all about
collecting photons efficiently. Oh -- and don't forget to dress warmly on cold nights. You could be standing or sitting perfectly still for several
hours, lack of movement means your body doesn't produce as much heat as you are used to having.
Your first problem will be adequate polar alignment -- assuming you are trying to shoot some of the dimmer objects. Some scopes will roughly align for
you if you sight in a couple of stars. But the better you align the mount yourself, the fewer issues you will have with error in tracking. The
equatorial mount turns a lot more smoothly too IMO with better alignment.
Start simple -- there is a lot to learn. You can start getting a feel for this type of photography by mounting your camera with a wide angle or a
telephoto lens on top of your telescope as if the telescope was a simple tripod. Focusing will be tougher than you think -- stars are already points
of light. Take some photos of the Milky Way with different time exposures and aperatures. Try some long exposures. There will be a point where the
sky begins to "wash out" if you aren't in a really really dark place. You can also try photographs of the moon with a long telephoto both with and
without tracking. With a standard 50mm lens or a wide angle lens, you will avoid much of the tracking problems while learning about light, exposure,
focusing, and movement in and around your camera and scope.
After you get a feel for this, try some simple photos of large planets, bright nebulas, colored bright binaries, or larger open clusters -- use
natural projection onto the film plane from your telescope at first. Projecting magnification through an eyepiece and an extender tube onto the film
plane will be much harder than you think. If this is for you, you will get there soon enough. When you do any of this, you will have to learn how to
find and focus on dim objects using your camera viewfinder -- even finding objects with the camera attached can be tricky. You may want to invest in
a laptop to make it easier and drive the scope "remotely." Canon has software which you can use to control cameras like a 50D or 7D via the laptop.
That's more equipment to manage, and more expensive stuff to trip over. BTW: you may want to invest in a cover for your camera viewfinder if any
light leaks back into the camera from that side.
After the initial stage, when you begin to project into the film plane using your scope as your new super, upside down, telephoto lens attached via
the T-ring mount, this could be a good time to experiment with "stacking" photos of shorter duration to make a single photo. At a later point, you
might even want to use filters (like an O III) to enhance some photos.
As you progress past the initial piggyback camera stage, you might want to try piggybacking a smaller scope with your camera attached on top of your
larger scope. This can eliminate issues trying to find dimmer objects through the camera and definitely helps with fine-tune the guiding. Guiding
errors, when small enough, look like stars with points on one end. Use the larger scope to track and the smaller one for the photo. As you advance
you might invest in a guide tool which "borrows" a star from the projected field to use as a guide star for correcting tracking errors but it will
take time to learn how to use them effectively. Save that for a year or so down the road.
I don't know a lot about your camera. You should know which way the shutter moves to avoid bigger shake or prolonged shake in a direction which
resonates with the mount and drive. You may want to change your focusing screen eventually to one which is brighter if that is possible with your
camera. Forget about autofocus, it's not good enough IMO. Also, batteries drain faster when it's cold out -- most of the really good stuff is up
when it's cold. If your camera can hold open the shutter without power, that's goodness.
Also, I always hold a black screen in front of my scope for a few seconds after releasing the shutter (with a cable release or timed release) to
prevent the shake of the shutter release from messing up the photo -- and do the same prior to ending the exposure. Don't move your feet (and avoid
windy nights), if shooting through the scope as that will usually cause a little shaking too. You will learn too, to avoid nights where the seeing
cells are small -- night with stars twinkling is not a good night for photos unless you stop down the telescope.
If this is a little overwhelming to start -- take it in steps. No matter how much you read about it, it's never as simple as it sounds. Good astro
photos take time (lots of time) and patience. And much trial and error. If you end up with one decent photo over a whole evening, you are doing
better than you think.
edit on 30-11-2012 by BayesLike because: (no reason given)
edit on 30-11-2012 by BayesLike because: (no