Melotte 20 - Alpha Persei Cluster in Perseus (Secondary Upgrade) (Jonathan W MacCollum)

Celestial hemisphere: Northern · Constellation: Perseus (Per) · Contains: 29 Per · 31 Per · 33 alf Per · 34 Per · Mirphak · Perseus · The star 29Per · The star 31Per · The star 34Per · The star Mirfak (αPer)

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Melotte 20 - Alpha Persei Cluster in Perseus (Secondary Upgrade)

Link: https://www.darkflats.com/Deep-Sky/Perseus/Mel20.Mosaic2.TrimEdges.Saturate.ArcSinhRGB.GHSL.Combine.Full.3.jpg

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Melotte 20 - Alpha Persei Cluster in Perseus (Secondary Upgrade)

Link: https://www.darkflats.com/Deep-Sky/Perseus/Mel20.Mosaic2.TrimEdges.Saturate.ArcSinhRGB.GHSL.Combine.Full.3.jpg

A new secondary configuration is in progress! I finally took the plunge and upgraded my secondary mirror configuration. I decided to give the TS Optics holder and spider a try, and after much effort I have got it up and running. There's much more work to be done to eliminate the extra extended and twisting spikes but otherwise really happy with this build.

The test target: A four panel mosaic of Melotte 20, a large star cluster in Perseus with the bright star Mirfak. I've been eyeing this cluster in the all sky cam for the past few months, and thought there's no better time to try it than under the full moon. Sadly, the moon was too close, so the gradients were extremely difficult to manage and prevented flats from accurately remove dust motes in the subs. I ended up having to use a night-sky flat technique to produce a synthetic flat tailored to the dust motes specifically to double-calibrate the data with.

Each panel was made using 15x90s per R, G and B filter and had it's RGB masters combined into a color image, color calibrated using photometric color calibration, DBE (more agressively than usual) solved, and then re-projected using Mosaic by Coordinates, then edges trimmed and star cores color repaired using HSV Repair Separation.

The four panels were combined using Photometric Mosaic, Re-DBE'd. A synthetic luminance was extracted and stretched using Generalized Hyperbolic Stretch (GHS). The color data was saturated and then stretched using ArcSinh Stretch. The luminance was re-added to the color image to produce the final image. To share on the web, it was downscale 2x and an ICC Profile was applied for blackpoint compensation.

Let me know your thoughts! CC is always welcome!

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	Distinct awarded users	Total awarded images
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This table shows the distribution of awards per subject type, compared to the popularity of images of that subject type.
	Image of the day	Top pick	Top pick nominations	Total submitted
Deep sky
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Distribution of data sources

This table shows the distribution of awards per data source, compared to the popularity of images acquired from that data source.
	Image of the day	Top pick	Top pick nominations	Total submitted
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Other
Unknown

The “AstroBin Image of the Day and Top Picks”, or IOTD/TP, is a long-running system to promote beautiful, interesting, peculiar, or otherwise amazing astrophotographs, with a focus on technical excellence. Learn more.

Submitted The date and time when you submitted this image for IOTD/TP consideration.	...
Views by Submitters (available since September 19th, 2023) Every image is assigned to 50% of available Submitters. In the event that at least 80% of them don't view the image before its time in the IOTD/TP process expires, it's assigned to the other 50% of Submitters and the process begins anew.
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Promotions by Reviewers When 3 distinct Reviewers promote the image, it moves on to the next stage of the process: evaluation for IOTD status.
Early dismissal Staff members have a lot of images to inspect on a daily basis, and they can dismiss images if they believe they don't meet the requirements for IOTD/TP selection. If an image is dismissed 5 times, it's removed from the process. This streamlines the process and ensures that any bias present in promotions could be overruled by other staff members.

Status	Advanced success
Started	...
Astrometry.net job	5410361
PixInsight job	QHQQYRCMFRY6FIE4XSM730RGJRTHB332
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	03h25m22s.66
RA (top/left)	03h33m13s.11
RA (top/right)	03h17m33s.50
RA (bottom/right)	03h17m48s.27
RA (bottom/left)	03h32m57s.81

Dec (center)	+49°32′48″.8
Dec (top/left)	+50°20′54″.3
Dec (top/right)	+50°20′55″.9
Dec (bottom/right)	+48°42′45″.1
Dec (bottom/left)	+48°42′45″.1

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Melotte 20 - Alpha Persei Cluster in Perseus (Secondary Upgrade)

Melotte 20 - Alpha Persei Cluster in Perseus (Secondary Upgrade)

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Melotte 20 - Alpha Persei Cluster in Perseus (Secondary Upgrade)

Melotte 20 - Alpha Persei Cluster in Perseus (Secondary Upgrade)

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