The Crab Nebula | A Broadband-Narrowband Mix (Kevin Morefield)

Celestial hemisphere: Northern · Constellation: Taurus (Tau) · Contains: Crab nebula · LBN 833 · M 1 · NGC 1952 · Sh2-244

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The Crab Nebula | A Broadband-Narrowband Mix

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The Crab Nebula | A Broadband-Narrowband Mix

It's hard to come up with something different for M1. Everyone shoots it (as they should!) and it's within reach of short and long FL systems. If this one is different it's only because its so middle-of-the-road! I was torn trying to choose between a vibrant narrowband version and a subtle broadband version so in the end I tried to do both at the same time.

The color mix here was done in Pixelmath by averaging the broadband and narrowband data in a linear state. The mix was something like this:

RED: Ha*.4 + SII*.2 + Red*4
GREEN: Green*.4 + OIII*1.2 - SII/3 (this is from memory so may be a little off)
Blue: OIII*.5 + Blue *.5

I subtracted the SII from the OIII to allow the Reds and Blues to be less muddied by having the same data in Green. The SII here is pretty similar to the bright parts of the Ha data. This also helped the Blue be more blue and less teal. PI Background Neutralization and Color Calibration tools balance the colors out.

The Luminance Channel was this:

LUMINANCE: Ha*.3 + SII*.2 + OIII*.3 + Luminance *.2

Additional luminance data was blended into the background with a mask to improve background noise. The stars are RGB data.

Deconvolution and sharpening were done in CCDStack. Noise reduction was via Adobe Camera Raw. The star mask was done with RC-Astro's StarXterminator tool.

The data here spans 4 years, three cameras, and two mounts. It really took a while to get decent data to work with. The Image scales were .73", .60", and .30". I registered and rescaled everything to the .73" data. I found that upscaled produced a less smooth background and since the data is almost all above 2" FWHM I had about 3 pixels at .73" to resolve things well enough.

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Distribution of astrophotographers

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	Distinct awarded users	Total awarded images
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Top picks
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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
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Star trails
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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
Backyard
Traveller
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Amateur hosting facility
Public amaeteur data
Professional, scientific grade data
Mix of multiple sources
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.
Promotions by Submitters When 3 distinct Submitters promote the image, it moves on to the next stage of the process: evaluation for Top Pick status. This requirement, in addition to anonymization of images and distribution to only a subset of them, prevents biases and ensures that the best images are selected.
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	5506471
PixInsight job	SSNJRABCJECEOFHHIP3OS7T9GNSVEOGB
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	05h34m34s.702
RA (top/left)	05h34m25s.216
RA (top/right)	05h33m28s.430
RA (bottom/right)	05h34m44s.132
RA (bottom/left)	05h35m41s.416

Dec (center)	+22°01′13″.62
Dec (top/left)	+22°17′09″.32
Dec (top/right)	+21°56′45″.48
Dec (bottom/right)	+21°45′17″.42
Dec (bottom/left)	+22°05′39″.91

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The Crab Nebula | A Broadband-Narrowband Mix

The Crab Nebula | A Broadband-Narrowband Mix

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Image Index:

Contribution Index (beta):

The Crab Nebula | A Broadband-Narrowband Mix

The Crab Nebula | A Broadband-Narrowband Mix

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