Abell 21 - Medusa Nebula (Massimo Di Fusco)

Celestial hemisphere: Northern · Constellation: Gemini (Gem) · Contains: PK205+14.1 · Sh2-274

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Abell 21 - Medusa Nebula

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Abell 21 - Medusa Nebula

The Medusa Nebula is a planetary nebula in the constellation of Gemini and it is also known as Abell 21 or Sharpless 2-274. It was originally discovered in 1955 by astronomer George O. Abell, who classified it as an old planetary nebula. Until the early 1970s, the nebula was thought to be a supernova remnant. With the computation of expansion velocities and the thermal character of the radio emission, Soviet astronomers in 1971 concluded that it was most likely a planetary nebula. As the nebula is so large, its surface brightness is very low, with surface magnitudes of between +15.99 and +25.00 reported.

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	Distinct awarded users	Total awarded images
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	Image of the day	Top pick	Top pick nominations	Total submitted
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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	5541324
PixInsight job	EMOOTM85B9ES0UTKX930PITV8IHJRO77
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	07h29m02s.34
RA (top/left)	07h30m22s.54
RA (top/right)	07h30m35s.24
RA (bottom/right)	07h27m41s.99
RA (bottom/left)	07h27m29s.82

Dec (center)	+13°18′20″.5
Dec (top/left)	+12°46′12″.3
Dec (top/right)	+13°48′20″.1
Dec (bottom/right)	+13°50′22″.3
Dec (bottom/left)	+12°48′17″.7

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Abell 21 - Medusa Nebula

Abell 21 - Medusa Nebula

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Abell 21 - Medusa Nebula

Abell 21 - Medusa Nebula

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