SH2-274 - Medusa Nebula (HOO - LRGB stars) (Kurt Zeppetello)

SH2-274 - Medusa Nebula (HOO - LRGB stars)

Link: http://astroquest1.blogspot.com/

This neat looking object is known as the Medusa Nebula as it bears a resemblance to the snake-like hair of Medusa in Greek myths. It is also known as SH2-274 of the Sharpless catalog and Abell 21. It is located approximately 1500 ly away in the constellation of Gemini and may be my first Abell object! Originally this was thought to have been a supernova remnant, however, research done by Soviet astronomers concluded it was a planetary nebula.

A planetary nebula represents the final phase of a sun-like star, first transforming to a red giant, then to a hot white dwarf while releasing its outer layers. The Medusa is estimated to be 4 light-years across, roughly the same distance to the nearest star to our own sun (Proxima Centauri). The reddish colors are due to the large amounts of hydrogen gas while blue-green is from ionized oxygen. There is a least one small galaxy visible in the upper right background but there may be more.

I was going to do a straight LRGB version as I thought would be too small to see any detail but I changed my mind - moon and weather issues. Doing the Ha-OIII brought out the faint dusty gas area in the lower left. I really like the colorful star field so merged it with the HOO nebula using a star mask in PI. After several bending iterations I determined that red - Ha (100%), green Ha (30%) + OIII(70%), and blue (100%) gave the optimal detail and color variation. The image was cropped and probably could be cropped further, in fact many people would, but I like the star field it sits in so I wound up with this compromise.

Dates: 2-3-20, 2-14-20, 2-15-20, 2-19-20, 2-20-20, 2-21-20, 2-22-20

Original
Final
B

B

Description: I added a little color, I originally thought I did this.

Uploaded: ...

Imaged with APT
Northeast Imagers
N.I.N.A. Users

All - Most Recent First
Emission Nebula
Favorites-DSO
Planetary Nebula

	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	3289534
PixInsight job	1ILSCNVAFB0MXTD4JKXM98QOORWXTEHK
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	07h28m58s.100
RA (top/left)	07h26m38s.20
RA (top/right)	07h32m08s.71
RA (bottom/right)	07h31m20s.56
RA (bottom/left)	07h25m48s.84

Dec (center)	+13°18′16″.4
Dec (top/left)	+12°40′27″.6
Dec (top/right)	+12°56′28″.10
Dec (bottom/right)	+13°55′59″.4
Dec (bottom/left)	+13°39′53″.2

Image Index:

Contribution Index (beta):