I was hoping to find some help here in identifying a star that shows up on one of my images. It looks like it might be a Mira, but I cannot be sure. It's a star field in Cassiopeia. On the left is a screen capture from Stellarium. On the right is my image. The arrow points to the star in question. It's bright enough that it should have easy shown on the Stellarium chart and doesn't appear to be a hot pixel. Does anyone know what it is?
Taken on the evening of December 2nd, 2020 from Caledon, ON Canada.
Cassiopeia at 150mm focal length
Crop sensor DSLR
100 light frames
20 dark frames
2.5s per exposure
Field center from Astrometry.net plot
RA center: 0h 18' 31"
DEC center: +63° 36' 39"
I posted the image on AstroBin here: https://astrob.in/v39dqt/0/
I also posted the full image on AstroBin here: https://astrob.in/m8avqi/0/
The closest star I could find to it is at 00:12:45.78 +63:45:51.1.
The star shows plotted on the Variable Star Plotter, but it isn't marked as a variable. It's just slightly to the lower right of the center coordinates.
Field of view 90.0.
I checked Aladin and it appears that the star is NSV 87.
The star is indeed NSV 87 but it is not variable (this is the ASAS-SN light curve), so do not submit observations for it.
There are many reasons why a star may not be shown in commercial software like Stellarium. It depends on it being included or not in the catalogues used for their database.
This is a 11.5 Vmag. star but it is not in Tycho-2. If they are using Tycho-2 to plot stars, it won't show up.
Another possiblity is that you may be using a too bright limiting magnitude for a 11.5 Vmag. star to be displayed in Stellarium. Since it is a rather red star, your detector may be showing it much brighter than its visual magnitude and thus you will notice that inconsistency.
You may want to check other red stars to see if they appear brighter in your images than their catalogue values.