Eskimo NGC 2392

[physicus]

From last night, and one of a bunch of objects I'm revisiting from a year ago when I was DSLR only.  This with the Atik460/C9.25+reducer is 50 x 10 seconds luminance plus 30 x 20s each RGB.  Not sure what the secret is (besides seeing!) for getting any more detail out of this 48" dia. planetary, exposure wise.  I suspect any further improvement will mean sorting through multiple subs, planetary fashion?  Anyhow, a big improvement over my earlier efforts.

 

[laudropb]

Nice capture.

[ollypenrice]

Oooh yes, that's a cracker.

How could you do better? Remove the reducer and work at native FL. Prove to yourself the fallacy in the focal reducer 'F ratio myth.' (Runs for cover but links to this thread.)

Olly

[toxic]

now thats a nice Eskimo 

 

[physicus]

11 hours ago, ollypenrice said:

Oooh yes, that's a cracker.

How could you do better? Remove the reducer and work at native FL. Prove to yourself the fallacy in the focal reducer 'F ratio myth.' (Runs for cover but links to this thread.)

Olly

Yes, that's a nice thread - I'm working through it.   I saw this f-ratio issue discussed a while back in Stan Moore's piece for Gendler's Springer pub. "Lessons from the Masters".  Practically, for this type of subject, there are multiple influences at play, so we should be careful not to mix our drinks (not suggesting you are doing that btw).  These planetaries are an unusual instance of a DSO which we can apply lucky imaging to: just flashing through my 10s and 20s subs tells me that - one or two out of 30 were much clearer/stable; although for my image here I only extracted the obvious duds rather than cherry-pick the good ones.   I did, a year ago, image the Eskimo at f20ish with the c9.25 avec barlow and my Canon 7D, and photons per se weren't the problem, so the whole thing is worth a re-visit.  There must be some literature re seeing, that relates length of exposure time before the image is mush.  Do we know what the maximum periods of clear seeing (however defined) ever are?    

[ollypenrice]

7 hours ago, physicus said:

Yes, that's a nice thread - I'm working through it.   I saw this f-ratio issue discussed a while back in Stan Moore's piece for Gendler's Springer pub. "Lessons from the Masters".  Practically, for this type of subject, there are multiple influences at play, so we should be careful not to mix our drinks (not suggesting you are doing that btw).  These planetaries are an unusual instance of a DSO which we can apply lucky imaging to: just flashing through my 10s and 20s subs tells me that - one or two out of 30 were much clearer/stable; although for my image here I only extracted the obvious duds rather than cherry-pick the good ones.   I did, a year ago, image the Eskimo at f20ish with the c9.25 avec barlow and my Canon 7D, and photons per se weren't the problem, so the whole thing is worth a re-visit.  There must be some literature re seeing, that relates length of exposure time before the image is mush.  Do we know what the maximum periods of clear seeing (however defined) ever are?    

Interesting. I don't know about the seeing since I've long been wedded to long exposures. Lots of short ones for this kind of target would be new territory but if I got anywhere near your result here I'd be happy.

This whole question has taken a turn towards urgency for me because I've been offered a very clean and fully loaded Meade ACF 10 inch.

Olly

[swag72]

This is a cracking image - Well done, you've certainly done this faint little sucker justice