Cookie consent

AstroBin saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing AstroBin without changing the browser settings, you grant us permission to store that information on your device.

I agree
Contains:  NGC 3193, NGC 3189, NGC 3190, NGC 3187, NGC 3185
Getting plate-solving status, please wait...
HCG 44, LRGB, 1 Feb & 15-16 Mar 2019, 


            David Dearden
HCG 44, LRGB, 1 Feb & 15-16 Mar 2019

HCG 44, LRGB, 1 Feb & 15-16 Mar 2019

Technical card

Resolution: 1878x1387

Dates:Feb. 1, 2019March 15, 2019March 16, 2019

ZWO Blue 31 mm: 7x120" (gain: 139.00) -20C bin 1x1
ZWO Green 31 mm: 18x120" (gain: 139.00) -20C bin 1x1
ZWO Luminance 31 mm: 30x300" (gain: 139.00) -20C bin 1x1
ZWO Red 31 mm: 8x120" (gain: 139.00) -20C bin 1x1

Integration: 3.6 hours

Avg. Moon age: 14.86 days

Avg. Moon phase: 48.08%

Bortle Dark-Sky Scale: 5.00 job: 2588562

RA center: 154.463 degrees

DEC center: 21.920 degrees

Pixel scale: 1.719 arcsec/pixel

Orientation: 180.989 degrees

Field radius: 0.557 degrees

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

Data source: Backyard


Even though I have long been intrigued by the variety of galactic shapes in this cluster, it seems like this target has always given me fits such that I just can’t get a good result. I took the luminance data for this image weeks ago, but this has been a cloudier-than-usual season so I didn’t get color to go with it until recently. And even then I had issues, as apparently my guider locked on a hot pixel after the automated meridian flip so I threw away nearly all my R and B subs. As a result, it was a huge struggle to bring out any color in this image. There was also angular misalignment between the luminance and color subs, so I had to crop far more than I wanted (I’m not a fan of cropping my data any more than I have to, even though it would often frame things better if I cropped; I like to show everything the camera caught when I can). And the final image is still a lot noisier than I like. Anyway, it’s better than my best previous (which says something about my best previous) so here it is.

Date: 1 Feb, 15-16 Mar 2019
Subject: HCG 44
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 2.6.5dev6 (Win 10 ASCOM)
Camera: ASI1600MM-Cool, -20 °C, Gain 139 Offset 21
Acquisition: Sequence Generator Pro
Exposure: 30x300 L, 8x120 R, 18x120 G, 7x120 B
Stacking: Deep Sky Stacker 4.1.1 (64-bit) dark+flat (no bias), κ-σ stacking with κ = 1.5.
Processing: StarTools 1.4.341: Combined L, R, G, & B in StarTools (had to convert R, G, & B to tiff first for some reason (they wouldn’t load otherwise). Cropped, wiped, developed, HDR optimized, and used the color module. Deconvoluted, untrack denoised. The did the same treatment to the L by itself and to the RGB. I ended up layering the processed RGB on top of the LRGB as a color layer in Photoshop. Attempted some more denoising and used increase star color.



David Dearden
License: None (All rights reserved)

Sky plot

Sky plot


HCG 44, LRGB, 1 Feb & 15-16 Mar 2019, 


            David Dearden