M101 Taken 4/23/2020 (Doug Azwell)

M101 Taken 4/23/2020

M101, also known as the Pinwheel Galaxy, taken during quarantine on April 21st. The skies were in pristine condition after the passage of the major storm system which brought massive rains to the south and east of St. Louis. This night was one of the handful of good nights we have had in St. Louis for imaging since November 2019.

The Pinwheel Galaxy is a beautiful spiral galaxy some 21 million light years away in the constellation of Ursa Major (the Great Bear, same constellation which has the asterism known commonly as the "Big Dipper"). The galaxy is slightly smaller in diameter (around 100,000 light years) as compared to our home galaxy, the Milky Way, which is 150,000 to 200,000 light years across. There are prominent areas of nebulosity from various sources within this galaxy, the most prevalent being reflection nebulae (blue splotches, which is blue light reflected from the surface of dust or other particles) and emission nebulae (pink splotches, which are star forming regions).

Emission nebulae are among some of the more beautiful regions of the heavens. These areas are rich in the gases necessary for star formation and have high concentrations of hydrogen, oxygen and sulfur gases which fluoresce in the presence of high strength ultraviolet light from nearby hot, young stars. The most prevalent color emitted by these nebulae which the human eye can see is the hydrogen alpha emission which is deep, wine-red color. This along with the other colors of light emitted by other molecules mixed within the gases of the nebula give a characteristic pink color to these regions. There are excellent examples of emission nebulae in the Milky Way, the most prominent in the northern hemisphere being "The Orion Nebula" also known as M42.

Please note: The following tables are updated every 24 hours.

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.

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	Basic failed
Started	...
Astrometry.net job	3452178
PixInsight job	n/a
PixInsight queue size	n/a
PixInsight stage	n/a

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