M 83: A Lesson in Using the Wrong Scope for the Job (Alex Woronow)

M 83: A Lesson in Using the Wrong Scope for the Job

M 83: A Lesson in Using the Wrong Scope for the Job

OTA: RASA 14"
Camera: QHY168C (CFA)
Observatory: iTelescope

EXPOSURES:
Total exposure take: 552 x 2 minutes
Exposures used: 380 (12.7 hours)

Image Width: 1.4 degrees
Processed by Alex Woronow (2023) using PixInsight, Topaz, 3DLut, StarNet2, NoiseXTerminator and BlurXTermintor, SWT, AC_Restar

This disk-hogging data set was provided for free from iTelescope to subscribers. There were 552 pre-calibrated, 32-bit, 9500x6400 pixel OSC images. The "raw" data exceeded 375 GB and was postured to be a time-consuming processing exercise. However, the M 83 galaxy occupied less than 1.8% of the pixels in the image…crying out for an early cropping of the subs. I cropped them to 25% of their original size, reformatted them to 16-bit, and ran an evaluation code on the images to cut the number to about 63% of the original 552 subs.

The remaining data were more easily processed. However, remember that the tiny target was unsuited to the telescope and camera. Undoubtedly, detail was sacrificed despite the relatively high quality of the data. The data did show one problem: The stacked images of the stars had a bulging blue halo extending downward from their edges. However, my star replacement procedure removed those bulges nicely.

The best part of this data set may not be the image it produced but the education it provided.

Alex Woronow

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	7520275
PixInsight job	n/a
PixInsight queue size	n/a
PixInsight stage	n/a

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