John N. Gretchen III wrote:
10x240 seconds
Meade 8" Schmidt-Newtonian
Celestron Advanced Series GT
Sbig ST2000XCM
over-processed with AstroArt and Photoshop

Type of object: Galaxy
RA (J2000.0): 10h 44m 00.0s
Dec (J2000.0): +11° 42' 00"
Constellation: Leo
Magnitude: 9.7
Surface brightness: 13.5
Size: 7.3'x4.4'
Position angle: 13°
Object classification: SBb
Description: B,L,R,pgmbMN
Notes: Leo group


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I've wondered about the exposure time of a one shot versus mono with
filters. You work at f/4. When I run at f/10 but bin 2x2 with my 9
micron pixels (18 when binned 2x2) it is about the same as running at
f/5 as far as exposure is concerned. You are running f/4 but with
smaller pixels with slightly higher quantum efficiency. I don't know
how dark your skies are. I have a 6.5 limiting zenith magnitude when
there's no ice or moon in the way. That was the case when I took this
guy using 7x5 minutes for the luminosity and 3x5 for each color. Since
then I've found 10 minute subs are better and give less noise over the
same time. So I need to redo this but at 1:20 or nearly double your
40 minutes it appears the time penalty for mono isn't as great as I
thought it was. The core of this guy is very interesting if you process
it separately then combine the two you can bring out the three parts to
it. Two are connected by a blue arc.
http://www.usenet-replayer.com/cgi/c...6100237.4.jpeg

I see replayer has died as it hasn't picked up anything new since Jan 5
when George put up the Google Earth shots of Kopernik.

It appears color processing with your new camera is far easier than it
was with your old one. Is that the case?

Rick

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