Crab Nebula with O3 Extension (James E.)

Crab Nebula with O3 Extension

I did not actually plan to image the Crab Nebula as a dedicated Fall target this year, but it was conveniently located to be used as a "placeholder" target while waiting for other primary targets to rise in the east. While most have seen the Crab in SHO as a crazy-colored planetary or in LRGB as a muted but much more visual-like image, I decided to actually "go for it" and do full on SHO and RGB (with my color camera in a separate posted image).

While searching for Crab images here on Astrobin, I came upon an image by Tony Hallas who used an RCOS 14.5" f/8 classical Cassegrain and a Starlight Xpress 694 camera on an Astro-Physics 1600 mount. It was so impressive it made Astobin's IOTD on Mar 16, 2017. However, one unusual thing I noticed with Tony's image was a quite prominent OIII "extension" that was only faintly seen on others images or unintentionally processed away with curves on others deep images. Tony's was by far the most obvious extension imaged by with amateur equipment. Later, I also came across a super-detailed image on Astrobin taken a couple of years ago showing this feature in its full extent - but it was taken with the 2-meter Liverpool Telescope. (Note: In my research it's likely I have missed other amateur images that showed this feature in its full extent.)

So I set out to create a Crab SHO image with somewhat tamer colors and show the OIII "extension" with my C11. The extension is actually not too difficult a feature but required plenty of OIII data. I was imaging during a season with plenty of humidity and light fog and others with better skies will likely fare better on this target.

In another image post, I plan to upload the Crab in RGB with my ASI2600MC and possibly a separate SHO-RGB combine.

Imaged over several nights: Nov 4, 6-7, 9, 11, 13-15 and 16, 2020. RGB star data provided by my ASI2600MC on Nov 16.

Schmidt-Cassegrain Telescope (SCT) Imagers
NOVAC
N.I.N.A. Users
Images from the EdgeHD Series
ZWO ASI1600MM/QHY163M

	Distinct awarded users	Total awarded images
Image of the day
Top picks
Top pick nominations

	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

	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

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	4023386
PixInsight job	2RVWTK6M4CVQ6IQP04IYTUU3TTCNO6GT
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	05h34m32s.306
RA (top/left)	05h35m10s.840
RA (top/right)	05h35m08s.301
RA (bottom/right)	05h33m53s.643
RA (bottom/left)	05h33m56s.425

Dec (center)	+22°01′31″.13
Dec (top/left)	+21°49′25″.60
Dec (top/right)	+22°14′02″.91
Dec (bottom/right)	+22°13′37″.70
Dec (bottom/left)	+21°48′59″.99

Image Index:

Contribution Index (beta):