What's the longest exposure time I can expect with the Celestron NexStar 130SLT? Using a DSLR and the x2 barlow t-adapter?

[DaveyLeo10]

I know it's not an ideal scope for astrophotography and I'm not expecting anything special since I know about EQ mounts etc. If it could get up to 30 second exposures I'd be happy.

[Cornelius Varley]

It might be worth reading through this thread to see what others are achieving

 

[Scott]

What is it your trying to image?. what concerns me is that you're after long exposures whicch leads me to believe its deep space but if thats the case, you'll want to lose the barlow. If its planetary then keep the barlow but lose the long exposures.

Then there are other factors that come into play for long exposures. what is the light pollution like where you are? is your mount tracking? the list goes on

can I suggest the book https://www.firstlightoptics.com/books/making-every-photon-count-steve-richards.html ? its something of an aspiring imagers bible

 

[DaveyLeo10]

Thanks for the replies. This isn't my first scope, my main scope is the Nexstar Evo 9.25' with a wedge. Really I got the 130SLT is because I'm heading to Canada for two months where the skies are darker and I've always wanted a reflector. I use the Canon 60Da DSLR for my imaging. I have to use a Barlow because I won't be able to reach focus with my DSLR. I've done plenty of deep sky imaging I'm literally just hoping someone has tried using this scope for deep sky imaging. It's not the only reason I bought the scope, it will be mainly used for visual anyway.

[dph1nm]

Hmm - at the native focal length and that pixel size  you might get 30secs out of the SLT mount if you are lucky. With the barlow I guess you are talking half that at best. Still, being an alt-az you can't do much more than 1min anyway due to field rotation.

NigelM

[DaveyLeo10]

I would be happy with that. It just gets confusing when people talk about long exposure. To me anything over 60 seconds is a long exposure. 30 seconds would be more than enough because I'm sure I can get good results via stacking. Will see!

[dph1nm]

I suspect the individual SLT mounts might be variable. I have always done 30sec exposures on mine (at 660mm FL, 2 arcsec pixels - that's the SLT 102 refractor) and happily thrown away maybe 25% of the subs and been reasonably pleased with the results from the rest. However, I have a friend with the same setup who couldn't get anywhere with 30secs and went down to 15 sec.  His pics still look OK though.

NigelM

[DaveyLeo10]

Yeah I guess I won't know for sure until I get my hands on it and try for myself.