Question
Because the scope does not have any electronic connections for the REbel G, I figure the camera will operate as if there is no lens attached. Testing the camera settings with the lens removed, there does not seem to be anyway to have the camera meter or even to set the aperture manually. For astronomy, this is OK since the photographs are usually long exposures using “bulb”. However, I would also like to use the scope as a telephoto lens. The telescope is a 480 mm F6.8 archromatic refractor with excellent quality for visual observations. 1) Any suggestions on how to set the exposures value? (I don’t have a light meter.) 2) Any comments on using astronomical telescopes for photography?
Anwser
Your aperture is going to be fixed to that of the scope. The variable apertures are in the Canon lenses themselves not in the camera. The only variable that your going to be able to play with is shutter speed. The Rebel’s metering system will work without a lense attached. The aperture value will read as 0.0 but the exposure scale works properly. Basically you have to meter then adjust the shutter speed (spin the wheel) until the exposure scale reads zero and then your set. Obviously the meter won’t be worth jack for astro photos, all you can do is guesstimate the exposure time and bracket the photos for a while until you get enough experience (a roll or two if you take good notes) to properly judge the exposure time (then I’d still probably bracket a little). But for daytime telephoto shots the meter’ll work. Beware of taking color print film to just any old place for developing, I tried it at first but they underexpose my prints so that the sky is a dark gray, not black. Everything came out horrible, there were no difference between prints, so I couldn’t tell from the prints what the bracketing did, the negs showed a difference. Maybe a decent lab (pro), not a one hour drug store, but one that charges about $16 for developing a 36exp C-41 roll and printing 4×6’s, if given specific instructions would carry them out for you and you’d get something good. Since I’ve start my darkroom, I now just do black and white for astrophotos and most everything else too as I love my Watson bulk loader. But anyway with that i have total control over the photos and my results have improved 1000 fold over taking c-41 to the Walgreens for astro. Although I am into astronomy and photography, I am not heavily interested in astrophotography. Maybe once every two months I’ll shoot a roll or two just for fun. I’ve used my scope as a telephoto lens numerous times with decent results. I have a Celestron 80mm F11.1 achromatic refractor and a Rebel G. Haven’t tried eypiece projection though, only directly as a 900mm lens. Later,
Associated Telescopes Astronomical Question: What I don’t understand is why birdwatching telescopes costs so much more than much more powerful astronomical refracting scopes – especially since the prices of the latter have tumbled in the last few years. In my view folks watching birds are paying way over the odds for the optics on offer and I hope that when one manufacturer tumbles to this and offers good optics at “astronomy” (as opposed to astronomical ) prices, we’ll see some bargains.

• Anwser:There are a few issues about good birding optics that astronomy scopes do not address. One is the question of water – who looks at stars in rainy weather? Second is portablility, a star-gazer normally have a fixed setup close to his home, while the birder carries the gear around for hours. However, one thing that I have read is that the oculars of astronomy scopes are standard fitting, as opposed to birding where every brand has its own fitting. If you could freely use whichever ocular on the market, there would be more competition. And also the ability to compare what is really important: the expensive scope body or a better ocular?
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