Contains: M 64, Black-eye galaxy, NGC 4826
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M64, Black Eye Galaxy, OSC (UHC-S), 26 May 2016

Technical card

Resolution: 758x609

Dates: May 26, 2016

Frames: 44x300"

Integration: 3.7 hours

Avg. Moon age: 19.11 days

Avg. Moon phase: 80.11%

Astrometry.net job: 1094895

RA center: 194.166 degrees

DEC center: 21.694 degrees

Pixel scale: 1.869 arcsec/pixel

Orientation: 2.776 degrees

Field radius: 0.252 degrees

Locations: Mapleton Lateral Observatory, Mapleton, Utah, United States

Description

I've tried a couple of times this season to get this image. The first time, using 600 s subframes, wasn't good enough to post. I decided I had used the wrong filter (a UHC-S nebula filter) for this galaxy. But the other night I tried again, and forgot and used the UHC-S filter again. This time I used 300 s subframes. I processed two images stacked using Deep Sky Stacker, with and without 2x drizzle, and was not happy with either. Both looked quite noisy even in the core, and there was especially a lot of grainy color noise. I thought the filter had messed things up again, but then I processed the Nebulosity-stacked version and it looked much better, so I'm going with that version. (This is a little unusual, in that the DSS-stacked version is usually about as good as if not better than the Nebulosity-stacked version--I routinely stack both ways.) I used somewhat different processing on this image than usual: HDR equalize rather than optimize, and less color saturation. I’m still tempted to try again without the filter, however.

Revision: darkened the background with levels and a layer mask

Date: 25-26 May 2016
Subject: M64, Black Eye Galaxy
Scope: AT8IN+High Point Scientific Coma Corrector
Filter: Baader Planetarium UHC-S
Mount: EQ-6 (EQMOD)+PEC
Guiding: Orion ST-80 + Antares 0.5x focal reducer + DSI Ic + PHD 2.6.1.1 (Win 7 ASCOM)
Camera: DSI IIc, no chiller CCD 11 °C
Acquisition: Sequence Generator Pro 2.5.1.14 with Nebulosity 4.0.4 ASCOM camera driver
Exposure: 44x300 s
Stacking: Neb 4, bad pixel map, bias included, 33 flats, match histograms, trans+rot align, Neb 4 40-60%tile stack.
Processing: StarTools 1.4.316: Crop; Wipe; Develop: 87.97%; HDR:Equalize; Color:Scientific, 150% saturation, red bias reduce 1.35; Deconvolute: 2.2 pix; Track: Smoothness 87%, 4.5 pix; Magic, shrink 1 pix. Photoshop CS6 + Astronomy Tools: Deep space noise reduction (2x); lncrease star color; Astroframe.

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Author

David Dearden
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M64, Black Eye Galaxy, OSC (UHC-S), 26 May 2016, David Dearden