CTB-1 (Abell 85) Supernova Remnant (Starless) (Douglas J Struble)

CTB-1 (Abell 85) Supernova Remnant (Starless)

I don't believe all deep space images look good starless, but in this particular case there was a lot of background Ha partially obscured by a pretty thick star field. Unfortunately I had to reprocess everything all over gain, as I had originally ran deconvolution in PixInsight. Nikita's StarNet++ does not work so well with deconvoluted images due to the variations in how each person handles the process. So despite how well StarNet++ works, in my case it took some time.

CTB1 is a nearby supernova remnant (SNR) with an apparent diameter of about a half a degree (about the same size as a Full Moon). Upon early discovery, CTB1 was thought to be a planetary nebula, so Abell included it in his catalog of planetary nebulae as Abell 85. It was identified as a SNR by van den Bergh et al. in 1972 based upon its optical half-circular shape consisting of radiative filaments. Deeper images taken in H-alpha by Fesen (1993) show that it has a complete circular shape except for the unusual breakout structure toward the northeast, which also shows up in X-Ray images. Distance and age estimates are 10,000 light years, and 7,500 – 11,000 years, respectively. It spans nearly 100 light years.

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Distribution of astrophotographers

This table shows the number of distinct astrophotographers who have been assigned and IOTD/TP award compared to the total number of images awarded.
	Distinct awarded users	Total awarded images
Image of the day
Top picks
Top pick nominations

Distribution of subject types

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
Solar system
Extremely wide field
Star trails
Northern lights
Noctilucent clouds
Landscape

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
Backyard
Traveller
Own remote observatory
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.

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Status	Basic failed
Started	...
Astrometry.net job	2689192
PixInsight job	n/a
PixInsight queue size	n/a
PixInsight stage	n/a

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