Longest exposure possible with single axis equatorial platform

[Admiral Crispy]

Hi guys,

I was just wondering what the longest exposures I would be able to take with prime focus camera techniques using my single axis equatorial platform? Just I was thinking of using my mount and a camera to take images of pluto, M13, M57, M33, M81 etc., and was wondering if it would be worthwhile or not?

Any responses would be very greatly appreciated!

Thanks,

Chris

[bigal1]

I rekon it is sure worth a shot , try get the best polar alignment you can and if you keep the focal length rather short a minute or possably more maybe ?

[spaceboy]

I would sure like to see the results. I never got around to trying it with my EQP/250PX and always regretted not giving it a go.

[Admiral Crispy]

Do you think that around 30 seconds would give ok results, or could go up to a couple of minutes? Thanks for the replies!

[Quatermass]

Try it on M13 you can get away with 20 seconds or less I would have thought if your mount has a single axis motor you can get away with 80 seconds no problem.

http://www.astronomyforbeginners.com/astrophotography/prime-focus.php

[Admiral Crispy]

Thanks guys, I'm starting to go down the line of buying a camera to test it out, unless anyone knows why it wouldn't be a good idea?

[ismangil]

Thanks guys, I'm starting to go down the line of buying a camera to test it out, unless anyone knows why it wouldn't be a good idea?

Because you're starting on a dark path with a bottomless pit at the end

[Chris]

I manage to get 120 second subs reliably with a focal length of 388mm.

[Admiral Crispy]

That's a really long exposure! As my focal length is 1200mm, would I be advised to get a focal reducer to help my scope capture light quickly?

[Admiral Crispy]

Just tried some last night, and managed 30 seconds comfortbaly, when the wind wasn't causing trouble! Will try longer subs to really get some detail tonight!

[Tinker1947]

I just checked the polar alignment on my NEQ6 adjusted it so its about as good as it can get, and set the ISO to 100 and run off a 5 minute image, it had a tiny bit of star trail, 3 minutes appears good, 2 minutes or less would be pin sharp, but it does need to be accurate...