Hemisphere:  Northern  ·  Contains:  M 56  ·  M56  ·  NGC 6779
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M56, RGB, 17 June 2020, 


            David Dearden
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M56, RGB, 17 June 2020

Imaging telescopes or lenses: Astro-Tech AT8IN

Imaging cameras: ZWO ASI1600MM-Cool

Mounts: Skywatcher NEQ-6 Pro Synscan

Guiding telescopes or lenses: Astro-Tech AT8IN

Guiding cameras: ZWO AS120MM-Mini

Focal reducers: High Point Scientific Coma Corrector Photo & Visual For Netwonian Telescopes 2"

Software: DeepSkyStacker  ·  Noel Carboni's Astro Tools for PhotoShop  ·  StarTools  ·  AstroPlanner  ·  PHD2 Guiding  ·  Sequence Generator Pro  ·  EQASCOM  ·  photoshop

Filters: ZWO Red 31 mm  ·  ZWO Green 31 mm  ·  ZWO Blue 31 mm

Accessory: Orion Thin Off Axis Guider (TOAG)  ·  Robert Brown's Arduino ASCOM Focuser Pro DIY  ·  ZWO EFW filter wheel

Dates:June 17, 2020

ZWO Blue 31 mm: 15x180" (gain: 139.00) -20C bin 1x1
ZWO Green 31 mm: 15x180" (gain: 139.00) -20C bin 1x1
ZWO Red 31 mm: 15x180" (gain: 139.00) -20C bin 1x1

Integration: 2.2 hours

Avg. Moon age: 25.94 days

Avg. Moon phase: 13.89%

Bortle Dark-Sky Scale: 5.00

Astrometry.net job: 3625912

RA center: 19h 16' 20"

DEC center: +30° 11' 26"

Pixel scale: 1.718 arcsec/pixel

Orientation: 2.310 degrees

Field radius: 0.709 degrees

Resolution: 2348x1820

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

Data source: Backyard


32,900 ly

Continuing my string of globulars, I decided to image M56 while waiting for another target to clear the neighbor’s tree. I did straight RGB imaging with no dedicated L, as this has seemed to work reasonably well for bright targets like globular clusters. I’m pleased with how this turned out, especially given that I did not spend a lot of time either acquiring the data or processing it. I like the intense star colors, which came from the default StarTools treatment without any tweaking. As this object is close to the plane of the Milky Way, the star field is rich. According to Wikipedia, this globular has very low metallicity and is therefore regarded to be quite old (13.7 billion years); it is in a retrograde orbit around the Milky Way, so it is thought it was captured from a merger with a dwarf galaxy.

Date: 17 June 2020
Subject: M56
Scope: AT8IN+High Point Scientific Coma Corrector
Filters: ZWO 31 mm diameter unmounted R, G, B
Mount: EQ-6 (EQMOD 2.000j)+PEC
Guiding: Orion Thin Off-axis Guider + ASI120MM-mini +PHD 2.6.8 (Win 10 ASCOM)
Camera: ASI1600MM-Cool, -20 °C, Gain 139 Offset 21
Acquisition: Sequence Generator Pro
Exposure: 15x180 R, 15x180 G, 15x180 B
Stacking: Deep Sky Stacker 4.2.3 (64-bit) dark+flat+bias, κ-σ stacking with κ = 1.5
Processing: StarTools 1.6.394RC: Composed R, G, & B accounting for total integration times in creating a combined synthetic luminance. Cropped, developed (94%), HDR (reveal core), deconvoluted slightly (2 pixels), ran the color module with default settings, and untrack denoised. In Photoshop, slight levels adjustment to darken the background, plus a couple of rounds of Carboni’s “make stars smaller”. AstroFrame.



David Dearden
License: None (All rights reserved)

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M56, RGB, 17 June 2020, 


            David Dearden