M27, Dumbbell Nebula, UHC-S (with smoke!), 20 Aug 2015 (David Dearden)

M27, Dumbbell Nebula, UHC-S (with smoke!), 20 Aug 2015

I thought I'd try 600 sec subs on M27 and try to see the outer ring. The air was very smoky, but because I was imaging near the meridian I had hoped to get around that. However, when I went out looking for synch stars to get started, even the brighter stars were obscured. Conditions were bad. Synched from Albireo and had an easy goto, but had lots of trouble re-acquiring after the meridian flip (mainly because the angle made it hard to see through the Telrad and I forgot to tell the mount controller about the flip. I guess I need to suspend operations until this smoke clears out. Guiding performance was also sub-par, as can be seen from the football-shaped stars. So this image has lots of problems. I think it would be a lot better if not for the smoke.

Revision B: tried to clean up the football-shaped stars and darkened the background a little. Rotated 180° to align with older image. Maybe a case of "garbage in, garbage out."

Date: 20 Aug 2015

Subject: M27, Dumbbell Nebula

Scope: Astrotech AT8IN

Filter: Baader UHC-S

Mount: CG-5 (Synta motors, PicGoto Simplificado)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.5.0.1 (Win 7 ASCOM)

Camera: DSI IIc no cooling (about 23 °C)

Acquisition: Nebulosity 4.0.2, no dither

Exposure: 20x600 s

Stacking: Neb 4.0.2, bad pixel map, bias included, 33 flats, OSC nebula filter, histogram match, deBayer & square, align, DSS κ-σ stack with κ=1.75.

Processing: StarTools 1.3.5.289 Crop; Wipe: 75%; Develop: 74.99%; HDR:Equalize; Color:Scientific, 150%; Deconvolute 5.5 pix; Track 8.9 pix, smoothness 88%, read noise compensation 81.62%; Magic, shrink 1 pix. Photoshop CC 2014 + Carboni Astronomy Tools repeated layer-masked deep space and space noise reduction followed by less crunchy more fuzzy; liquify-pucker on large stars; Astroframe.

Original
Final
B

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Status	Advanced success
Started	...
Astrometry.net job	4065721
PixInsight job	0XV6JPX3JM9M4GFT7UWPQ6HXMQP9N59P
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	19h59m31s.51
RA (top/left)	20h00m33s.73
RA (top/right)	19h58m38s.36
RA (bottom/right)	19h58m28s.96
RA (bottom/left)	20h00m24s.14

Dec (center)	+22°42′58″.4
Dec (top/left)	+22°52′08″.7
Dec (top/right)	+22°55′11″.4
Dec (bottom/right)	+22°33′45″.4
Dec (bottom/left)	+22°30′52″.0

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