1st trial on M51

[Erquy]

Hi,

1st trial on M51.

Only 17 subs of 30 sec at ISO3200, with Skymax 102 AltAz goto and EOS1100d at prime focus. Conditions were not best. I am more than happy with the result, much better than I could imagine! For sure I will give it another go and this time better focusing and much longer time!

[Uplooker]

Hi Erquy,

Blimey, if that is just a trial i can't wait to see your proper go at it. very well done, I have never tried m51

Ian

[Leveye]

Awesome! What mm Lens here?

[Astrosurf]

Lovely job. Particularly for only 30 secs subs!

Alexxx

[Erquy]

this time, about 36*30 sec ISO3200. Skymax 102 prime focus (f12,7)

[Pete Presland]

great image, especially considering the short exposure time

[ndastgir]

Great shots! and not much noise for that high ISO.

[Chris]

Great job! imaging a DSO with a very slow f/12.7 scope on a alt/az mount is something not many people would even attempt!. I don't think you could go for much longer on the sub length due to the field rotation you get with an Alt/Az mount, maybe upto 40-45 seconds? The Canon 1100D is definately the camera to have when working with very short subs (ISO 3200 and low noise) The very low outside temp will be helping a lot with the noise also. As for focus you could make a Hartman mask which is basically a lid with 3 holes in arranged in a triangle, also there is a Y-mask you can make quite easily. Bahtinov masks are a bit more tricky to make but if you want one you might get one for your scope from FLO for about 15 pounds. For good focus a mask is essential, you can fix a lot of things in PS but you can't fix focus in hindsight. I look forward to seeing what else you produce with your un-orthodox DSO imaging rig:D Well Done!

[Erquy]

Hi!

Thanks for all comments. For sure I am really surprised still of what I can get out, when thinking about many posts basically saying "no go" for DSO with such a small scope/high F on Alt Az . Anyhow keep in mind only 70% of the shots are usable (little vibration on the mount which is not that sturdy and I think main limitation factor for going into longer exposure towards the field rotation limit, - not really an issue on field rotation as soon as I stay from 30 sec and below-).

I used a Bahtinov mask for the second one, but still not that easy. I think I need to decrease the subs exposure time to get sharper (when processing in nebulosity, when aligning using high stretching I could see I have quite a lot of subs to take away, maybe only 40-50% are really sharp shots, many does not show sharp round stars -again typically small vibrations, not straight lines-). So I need another 1-2 night to do as many more and more and select further more.

I also had good shots on Orion and Pleiades, see my gallery (taken at 15 and 25 sec respectively, again ISO3200), although a bit too much stretched and noise starts to come out also. I could do it more gently to get nicer contrast, but less details I think

http://stargazerslounge.com/gallery/member/27995-erquy/

But for sure, I have a nice sky in my garden with little light pollution (although I live in the suburds of a small town -15 000 inhabitants) and all pictures so far taken between -10C and 0 C.