Quote Originally Posted by Paul McSweeney


However a Canon 600mm f/4 hasa bigger aperture than the telescope you used, which was 600mm f/7.5 if I read it right. I have no idea which is more expensive. The canon lens is not cheap.


Then you said:


Quote Originally Posted by tkerr
BTW, you don't need a telescope mount to take pictures of the night sky. You will if you want to do something like these two pictures, but there are other things you can do also.

but that was my main point of surprise because the second shot was not from a telescope but instead a Canon 100-400mm f/5.6, yet it shows what I typically thought required a long focal length.
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Let me clarify that comment. I should have said you don't need a Telescope or a expensive Mount to take pictures of the night sky with a DSLR.


Those images are cropped down a little which is probably making it look more like an image from a longer focal length. They are about 80% of the original image.
Additionally, Pleiades, and Andromeda are pretty large Deep Sky Objects, you don't need a lot of focal length for those.





The Canon 100-400mm lens is three times the cost of my C80ED. I started using it out of curiosity to see what it could do, and it gives me the versatility that a fixed focal length refractor doesn't.
A Canon 600mm f/4 would most likely cost more than all my telescope and current camera equipment together.
The things I could do with such a lens. [^o)]