M 101 B 1x1 1-hour unguided (Jason Fields)

Celestial hemisphere: Northern · Constellation: Ursa Major (UMa) · Contains: M 101 · NGC 5447 · NGC 5449 · NGC 5450 · NGC 5451 · NGC 5453 · NGC 5455 · NGC 5457 · NGC 5461 · NGC 5462 · NGC 5471 · NGC 5477 · Pinwheel galaxy

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M 101 B 1x1 1-hour unguided

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M 101 B 1x1 1-hour unguided

This image shows what one can do with even a single long exposure.

This is a 1-hour (3600-sec) unguided image of M 101, to start to compare the effectiveness of different imaging strategies. The image has only had hot pixels and saturation blooms removed, no calibration applied. Obviously, histogram stretching has been applied. Seeing was a bit choppy and it appears the autofocuser did a reasonably job of keeping up with the 10°C temperature drop during the image; however, focus is soft and I may need to think more seriously about FocusLock.

There is a school of thought that says get above the read noise floor and coadd; this approach certainly has many benefits.

There is another school of thought that says "expose to the right", meaning, take a long exposure to get all the photons as one can and push the raw image histogram to the right. A key benefit here is getting the really faint extensions of an object (measured in tens of e-/hour) and the read noise penalty only once.

I tend to be a proponent of the former; however, there is the minor problem that any image processing method of combining (adding, subtracting, dividing, averaging, etc.) images introduces its own noise and uncertainty. Medians are nosier than means, but reject outliers better, etc. Noise always adds.

Also, this image is unguided; meaning, no guider inputs were provided to the mount. I ran the tip-tilt device at 1 Hz and every time I took at look at it, deflection was 1/5 of a pixel or less.

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	Advanced success
Started	...
Astrometry.net job	2618091
PixInsight job	WLSJ1EO9U32Z0UCQZK97J9HOL7HAQNA6
PixInsight queue size	n/a
PixInsight stage	n/a

RA (center)	14h03m12s.63
RA (top/left)	14h00m03s.43
RA (top/right)	14h06m23s.16
RA (bottom/right)	14h06m24s.77
RA (bottom/left)	13h59m59s.80

Dec (center)	+54°20′50″.9
Dec (top/left)	+54°01′46″.3
Dec (top/right)	+54°02′02″.2
Dec (bottom/right)	+54°39′37″.8
Dec (bottom/left)	+54°39′20″.8

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M 101 B 1x1 1-hour unguided

M 101 B 1x1 1-hour unguided

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Image Index:

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M 101 B 1x1 1-hour unguided

M 101 B 1x1 1-hour unguided

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Sky plot

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