Hubbles not-so-variable Cepheid in M33 (Bruce Van Deventer)

Hubbles not-so-variable Cepheid in M33

In 1926, Edwin Hubble presented a paper identifying 35 Cepheid variables in the "spiral nebula" M33. There were no other surveys for Cepheids in M33 until the 1970's, and in the 1990's there was an extensive photometric survey of the measurable stars in M33, the DIRECT survey. Recent survey data however shows that this might not be a Cepheid at all, and it's current nature is unclear. It is fairly bright and easy to find.

Marci, L.M. et. al.
https://core.ac.uk/reader/25307204

Image taken with the Meade 10" f/10 SCT, no reducer, ZWO ASI6200 camera binned 3x, 100 gain, 3 x 3 minutes unguided, no filter, 1 dark, no flats. A detailed astrometric solution from Astrometrica is shown in the inset as is the same star in a DSS field rotated to match the image with N/S on the horizontal axis.

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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	5067515
PixInsight job	n/a
PixInsight queue size	n/a
PixInsight stage	n/a

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