California Nebula : 3-Panel Mosaic (Paul Macklin)

California Nebula : 3-Panel Mosaic

Revision title: HOO with a warm filter

This is my first major project using my new Antlia ALP-T dual narrowband filter: a 3-panel mosaic on the California Nebula. The mosaic was planned and captured using Zwo's built-in methods in the asiair plus. I only had a single clear night, so I captured 40 x 5 min on each panel and integrated the best 3 hours, for a total of 9 hours integration time.

As with most of my mosaics, I extracted and processed Ha and [OIII] separately on each panel, then merged into separate Ha and [OIII] mosaics before recombining in HOO1 (i.e., natural colors) and HOO2 (more emphasis on Ha and [OIII] structures, and certainly more colorful!) For HOO2, I used 1.25x Ha and 5.0x [OIII], with the Ha green channel bumped up a smidgen.

Because there is so much nebulosity at the edges of panels, mosaic processing was challenging in AstroPixelProcessor, but I finally arrived at some good tricks:
1. Stack and process light pollution for Ha and [OIII] panels separately before mosaicing
* Use "reference" instead of "full" during integration, so that you have less junk on the edges.
* Take screencaps of where you place your squares for light pollution removal. Match square placement as much as possible on neighboring panels.
2. To start your mosaic, load your processed Ha and [OIII] panels in separate channels
3. Standard settings in registration:
* pentagon pattern recognition, scale 1 to 10
* use dynamic distortion correction
* disable "same camera and optics"
* registration mode: mosaic
4. Use "advanced" and "multiply-scale" in normalization
5. For integration:
* Integrate per-channel
* Do *not* use LNC in integration -- it introduces more artifacts than it's worth. You're better off spending more time in 1. If you must use LNC, use first degree, and at most 3 passes.
* I used 20% overlap in acquisition, and used 15% MBB blending

And that's it!

A: Mosaic in original colors, at half resolution
B-D: Mosaic in adapted HOO, at half resolution (variations of color balance)
E: Ha mosaic, full resolution
F: [OIII] mosaic, full resolution
G: HOO mosaic, full resolution (large file!)
H: Zoom background
I: iPhone background

B

Title: Modified HOO

Uploaded: ...

C

Title: HOO palette, with a bit more contrast

Uploaded: ...

D

Title: HOO with a warm filter

Description: Applied a mild warm filter to deal with some of the lingering blue cast.

Uploaded: ...

E

Title: Extracted Ha

Description: Extracted Ha, with a 20% APP stretch, linear contrast stretch, and noiseXterminator cleanup. Shown at full resolution.

Uploaded: ...

F

Title: Extracted [OIII]

Description: Extracted [OIII], with a 30% APP stretch, increased contrast stretch, and noiseXterminator cleanup. Shown at full resolution.

Uploaded: ...

G

Title: HOO - full resolution (Large file: 50 MB!)

Description: Full 1.2"/pixel resolution at 85% quality.

Uploaded: ...

H

Title: Zoom background

Uploaded: ...

I

Title: iPhone / Android background

Uploaded: ...

Deep Sky Mosaics
Hydrogen and Oxygen Narrowband Only!

	Distinct awarded users	Total awarded images
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Top picks
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	Image of the day	Top pick	Top pick nominations	Total submitted
Deep sky
Solar system
Extremely wide field
Star trails
Northern lights
Noctilucent clouds
Landscape
Artificial satellite

	Image of the day	Top pick	Top pick nominations	Total submitted
Backyard
Traveller
Own remote observatory
Amateur hosting facility
Public amaeteur data
Professional, scientific grade data
Mix of multiple sources
Other
Unknown

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Status	Advanced success
Started	...
PixInsight job	5ND87Q38MY8UZJ7KQ666RBQLVEO66MWD
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	04h01m57s.28
RA (top/left)	03h52m50s.84
RA (top/right)	03h53m02s.34
RA (bottom/right)	04h10m50s.10
RA (bottom/left)	04h11m07s.18

Dec (center)	+36°33′01″.6
Dec (top/left)	+37°33′18″.1
Dec (top/right)	+35°31′12″.6
Dec (bottom/right)	+35°30′12″.5
Dec (bottom/left)	+37°32′23″.6

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