M45, The Pleiades, LRGB, 6-9 Nov 2018 (David Dearden)

M45, The Pleiades, LRGB, 6-9 Nov 2018

After what is becoming a yearly practice of taking an October hiatus (thanks to a NSF proposal deadline and a brutal set of other deadlines at work; yippee for Halloween!), I decided to resume imaging with a nice, bright target, the Pleiades. This is a 2-panel mosaic that presented quite a few problems for me as I tried to merge the panels. I don’t usually use 2-minute subframes, but this is so bright it seemed appropriate. I think it’s my best M45 so far, and this is one of the earliest targets I ever attempted, back when I was doing afocal astrophotography. I still love attempting it.

Date: 6-9 Nov 2018

Subject: M45, The Pleiades

Scope: AT8IN+High Point Scientific Coma Corrector

Filters: ZWO 31 mm diameter unmounted 7 nm L, R, G, B

Mount: EQ-6 (EQMOD 2.000j)+PEC

Guiding: Orion Thin Off-axis Guider + DSI IIc +PHD 2.6.5 (Win 10 ASCOM)

Camera: ASI1600MM-Cool, -20 °C, Gain 139 Offset 21

Acquisition: Sequence Generator Pro 3.0.2.140

Exposure: 114x200 L, 46x120 R, 40x120 G, & 44x120 B

Stacking: Deep Sky Stacker 4.1.1 (64-bit) dark+flat (no bias), κ-σ stacking with κ = 1.5.

Processing: StarTools 1.4.332: Software binned all subs 2x2. Vignette wiped the luminance, color & gradient wiped the RGB, stretched, and HDR optimized. Deconvoluted and untrack denoised. Used Photoshop to combine L with RGB, then used photomerge with a lot of fiddling with layer masks to try to get the backgrounds matched and get rid of the numerous reflection artifacts I had with such a bright star field. Used a couple of rounds of Astronomy Tools’ increase star color, then AstroFrame.

Original
Final
B

B

Description: The earlier version of this image has been bugging me because of the bad job I did addressing the background gradient. This is my attempt to fix it.

Uploaded: ...

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Status	Advanced success
Started	...
Astrometry.net job	3368108
PixInsight job	GQF061PR3YA31HDBPU6M0S4QW5PGM7VA
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	03h47m02s.87
RA (top/left)	03h50m28s.50
RA (top/right)	03h43m47s.58
RA (bottom/right)	03h43m31s.80
RA (bottom/left)	03h50m11s.54

Dec (center)	+24°06′23″.6
Dec (top/left)	+24°33′59″.1
Dec (top/right)	+24°41′07″.7
Dec (bottom/right)	+23°37′04″.6
Dec (bottom/left)	+23°32′02″.5

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