M31, Andromeda Galaxy, DSI IIc + Quantaray, 11 Oct 2015 (David Dearden)

M31, Andromeda Galaxy, DSI IIc + Quantaray, 11 Oct 2015

More experimentation with the Quantaray zoom lens. Another large, easy target. I'm finding this lens is optically pretty slow compared to what I'm used to (I think it is f/5.6), so for the first time ever I went to 15 minute subframes (which is not hard when imaging at these large scales). I also used Nebulosity fine focus to try to improve the focus, which is more difficult with this lens and does not hold very well either. I had a set of 10 subs that were very tightly focused prior to performing a meridian flip; subs after the flip were not as good, but this image includes all of them less a few thrown out by Deep Sky Stacker's quality estimator. The results are encouraging enough I guess I'm going to need to find a better way to mount this rig.

In revision, darkened and desaturated to de-emphasize the star field and emphasize the galaxy.

Date: 10 Oct 2015

Subject: M31, Andromeda Galaxy

Scope: Quantaray 28-90 zoom lens at 90 mm setting

Filter: Baader Fringe Killer

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

Guiding: Orion ST-80 + DSI Ic + PHD 2.5.0.1 (Win 7 ASCOM)

Camera: DSI IIc, no chiller CCD 15 °C

Acquisition: Nebulosity 4.0.3, no dither

Exposure: 20x900 s

Stacking: Neb 4, bad pixel map, bias included, 33 flats, match histograms, deBayer & square, trans+rot align, DSS 2x drizzle 1.75 average κ-σ stack.

Processing: StarTools 1.4.305 Crop; Wipe 75%; Develop 79.51%; HDR optimize; Deconvolute 4.5 pix; Color: scientific, 250%; Life: moderate; Track 6.0 pix, Smoothness 88%; Magic: shrink 1 pixel. CS6 Astronomy Tools deep space noise reduction; space noise reduction; local contrast enhance; increase star color; make stars smaller; liquify/pucker; levels; enhance DSO and decrease stars; Astroframe.

Original
Final
C

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Status	Advanced success
Started	...
Astrometry.net job	4092741
PixInsight job	XDS4IZJ3AMQKT3NC1P8UO8AFB3N3Z98X
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	00h43m25s.10
RA (top/left)	00h34m57s.1
RA (top/right)	00h33m21s.0
RA (bottom/right)	00h51m12s.5
RA (bottom/left)	00h54m18s.9

Dec (center)	+41°17′12″
Dec (top/left)	+43°53′49″
Dec (top/right)	+38°56′57″
Dec (bottom/right)	+38°38′06″
Dec (bottom/left)	+43°34′07″

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