AstroTrac with a small short tube refractor?

[williamnohair]

Hi everyone I am contemplating buying a Televue 60 to mount on my AstroTrac but am a bit worried that a tripod and Manfrotto head will be a bit wobbly for taking pics especially with a DSLR hanging on the back of it. Has anyone tried a short tube refractor on an Astro Trac?

http://www.scsastro.co.uk/catalogue/tele-vue-60-refractor.htm

Thanks

WNH

[nmoushon]

I believe the astrotrac was intended for DLSR+lenses not DSLR+telescope. At 10" long + adapter + DSLR I think that would prove not so good a combo for that mount. The leverage it would create would only prove a hindrance for you. Plus for that kind of price I would suggest put that towards a good lens. You could get a very good/fast wide angle or telescopic lens for that kind of money. Which is what the Astrotrac was designed for.

Heres a couple wide angle/fish eyes that are much much faster than that scope and are about the same price or cheaper:

http://www.usa.canon.com/cusa/consumer/products/cameras/ef_lens_lineup/ef_15mm_f_2_8_fisheye - This fish-eye is an ultra widefield lens that is super fast at f2.8 that can create some very beautiful images! It does create some field distortion so the entire image wont be flat. But thats the esthetics that draws people to the fish-eye.

http://www.usa.canon.com/cusa/consumer/products/cameras/ef_lens_lineup/ef_s_10_22mm_f_3_5_4_5_usm - This is a decent wide field lens. Not as wide or as fast as the fish-eye (but at f/3.5-4.5) but wont get field distortions like the fish-eye would. Dont saying the field distortion on the fish-eye is bad just that it has an esthetic quality to it that doesnt lend itself to every person or image shoot.

Heres a couple telescopic lenses that are much faster than that scope and are about the same price or cheaper:

http://www.usa.canon.com/cusa/consumer/products/cameras/ef_lens_lineup/ef_200mm_f_2_8l_ii_usm - This is only 200mm vs 360mm FL but is f2.8! You would gather SOOO much more light than f/6 (f/6 is actually kinda slow for AP) which would mean shorter sub lengths and short number of subs need! Just a not though that this is a prime lens so its set at 200mm and cant zoom-in or zoom-out. But a telescope is basically a prime lens also.

http://www.usa.canon.com/cusa/consumer/products/cameras/ef_lens_lineup/ef_400mm_f_5_6l_usm - This ones is 400mm rather than 360mm FL and it faster. About the same length but I think would perform better than that scope. This might be a bit more expensive but you get much more FL and its a bit faster. This is also a prime lens.

These are just examples and I'm sure you could find more variety and cheaper prices since I took these directly from Canon website but you can see you can get a lot more for your money if you go with lenses on an astrotrac. The mount will perform better I think too. If I was going to spend that kind of money on a lens I would save up a bit more and get the 200mm and one of the wide angles. Its a great combo for everyday photography too. But if your wanting to 'zoom-in' on more AP targets then save up a bit more and go with a lens like the 400mm.

This is just me though. Dont have too much experience with lenses and someone else might have better suggestions.

[GlassWalker]

Weight wise, I've used an astrotrac with a 300mm f/2.8 which is 3kg + camera and all the rest. The manfrotto tripod that comes with the astrotrac travel kit isn't far off its stability limit though. And of course you need spot on polar alignment if you want exposures of any length at that focal length.