Hi all

im just starting out in astrophotography and just curious as to what is best to use. I'm looking at getting a Meade DS2102 Goto Maksutov Telescope but..im not sure what i should get to get camera/lense/filter wise to get a good picture.

I'm looking at taking photos of nebulae and later in the spring, saturn, as well as anything else i can find while poking around with my telescope.

any help would be greatly appreciated

That certainly isn't a scope I'd pick for deep sky photography, even for a beginner. It is alt azimuth limiting you to only 30" exposures. You'd need to use a strong compressor to get the focal length down to where guiding errors wouldn't be a major problem.

For a beginner in deep sky photography you want a short focal length scope so you have a decent chance to guide it well. It should be equatorially mounted as stacking short exposures is something you'll quickly outgrow. Do they make a wedge for this scope?

Start with a good mount then put a short focal length scope on it, I started at 600mm focal length and was very glad I did. It made the move to longer focal lengths much easier. Keep in mind that at f/13.3 you'd need 4.5 times the exposure time on a nebula or galaxy than you'd use at f/6.3 for instance. The longer you expose the more chance for Murphy to do his thing. Short focal lengths make it much easier to find the object on the CCD. Simple Goto scopes like this one have mounts that aren't all that accurate at goto. They will put the image in a low power eyepiece much of the time but likely miss a typical entry level CCD most of the time.

If you already have a short focal length scope (aperture not really important as you might think) I'd start with that and get a good equatorial mount with inputs for a guider CCD, either one built into the camera or separate.

The scope you suggest will work for planetary shots though I'd prefer more aperture, 6" minimum but it isn't designed for deep sky work at all.

As to the camera, that depends on your budget after getting the mount and possibly a scope if you don't already have one that will work. Beginners do find it easier to start with many short exposures stacked. This can't go as deep or as noise free as longer exposures but it does allow you to throw out the bad frames (but not if you use Track and Accumulate which I'd avoid for that and other reasons). For short frames to work it is best to get a camera with a low read out noise level. A Sony chip might be best here. They are found in many beginning cameras partly for this reason. It is often advised to match the pixel size to the local seeing so you don't over or under sample the image. Yeah, for the experienced deep sky shooter this is a good thing but undersampling (too big a pixel) is often a good thing for a beginner. It results in shorter exposures and hides a lot of errors or at least makes them less obvious. Starting with a short focal length scope (under 900mm) means about any CCD will have pixels of a reasonable size for a beginner. Anything in the 7 micron or larger size would work for you. I started with a 9 micron pixel on a 600 mm focal length scope which is a 3" pixel and severely undersampled but the other errors I made at the time completely hid this from view. I've attached one of my very first attempts to show you how such a short focal length works. It is M63 and has been enlarged 2x times yet the undersampling doesn't really show. Though collimation errors sure do!! It was taken with 10 5 minute frames stacked. A non antibloom camera was used. You'd prefer one with an anti blooming gate. These aren't as light efficient but you don't have the nasty blooms to repair. I didn't repair the one in this shot.

Note that even with such a short focal length my field of view was only 25 x 35 minutes of arc, less than one quarter of a square degree. Finding the target was sometimes interesting to say the least. Longer focal length would have so frustrated me I'd likly have come close to giving up.

Rick

Attached Images

M63-60min200%1.jpg (90.0 KB, 22 views)

short tube equatorial is probably best for the scope. A Mak with a wedge might work. Dobs are great for eyepieces but not for photography.

The camera would ideally be a DSLR (or SLR if you like film, but Digital is so much easier, and anymore, about as good). With a DSLR and an adapter, you can mount the camera body to the scope and use the scope as the "lens" (even if it is a reflector). If you want to take wide-angle shots as well, or use the camera as a non-astro camera, you need a lens of course. The one that comes with the camera is probably a good start, or get a wide-angle if you want wide field of view, or a telephoto if you want something between the scope and an ordinary camera lens.

As for filters--I use a minus-UV filter for non-astro photography (and it doesn't hurt astro photography, and it is much cheaper than a new lens, so leaving it on the lens is good protection for the lens against scratches and dust). If you have light pollution, you could try a light pollution filter--there are cheap ones that take most light pollution out and dim the stars and nebula just a little too, and expensive ones that only take out specific bands (like for mercury vapor lamps, if that is the only light pollution you have), or expensive nebula filters that take out everything but what the nebula emits--and which kind you would get depends on which nebula you photograph!

For planetary photography (not so good for nebulae), many people have good success with a web cam and an adapter that converts the web cam's threads to a 1 1/4in eyepiece. The web cam takes literally 1000s of frames, and the software picks out the best 50 or so and stacks them. This is similar to Mount Palomar's "Lucky Cam" which allows the earth-based telescope to give pictures that are competitive with Hubble images (throwing out all but the best images does much to compensate for atmosphere).


My personal setup:

Celestron C6-R 6in refractor with CG-5GT (it's f/8 so this is a medium-long-tube equatorial) equatorial go-to mount (I use the go to for tracking--if I spend a lot of time getting it well-aligned, it works well--if I were REALLY serious, I'd attach something to the finder scope to track a guide star, but I haven't advanced to that yet).

I have a 2in adaptor--I think I got it from Meade but I can't remember--it fits in the 2in eyepiece opening, and the other end is threaded for a T-adaptor made specifically for my camera.

The camera is a Canon EOS Digital Rebel XTi.

In addition to the general-purpose lens that came with the camera (zoom lens: 50mm and 75mm are in the range if I remember right), I have a telephoto zoom lens (100mm to 300mm I think, maybe 400mm). I have a minus-UV filter (and a lens hood to knock out some of stray light) on the expensive telephoto lens. (later, I might buy a right-angle viewfinder adapter for the camera--that magnifies the viewfinder in addition to making it more accessible to the eye when on a scope, and makes it easier to focus by eye). I have no 2in light pollution or nebula filter (yet)--just 1 1/4 in for use with eyepieces.

I can mount the camera piggy back on the scope, or I can use my separate el-cheapo camera tripod for non-tracking shots and terrestrial shots.

To process it all, I use MLUnsold's ImagePlus, which I highly recommend (9 out of 10 stars--a few awkwardities, but almost perfect otherwise). If you track well, it aligns and stacks while you walk away and watch TV. If you track poorly or not at all, you have to click on stars on each frame, and then you can watch TV while it aligns to those stars. The software understands Canon's Raw format, so that is what I use for pictures.

Many like the XTi for astrophotography--but it's not perfect--you can lock the mirror (to prevent vibration), but then it's harder to automatically take photos. I don't get much vibration myself from the mirror, just from kids touching the scope at a star party (but I limit to 30sec exposures and stack, so at worst I lose a frame here and there for that). The Canon 20DA is supposed to be good, if you can find one!!! Or, there are companies that will modify an XTi (I've never tried any) to make it more astro-friendly (e.g. remove the built-in minus-infrared filter to get more of red nebulae).

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Todd (Bowie, MD, US, North America, Earth, Sol System, Vega region, Local Bubble, Orion arm, Milky Way Galaxy, Local Group, Virgo A Cluster, Virgo supercluster, the universe in which spock is clean shaven)

Quidquid latine dictum sit, altum sonatur.

personal page: http://blog.astrosketches.info