Affiliation
American Association of Variable Star Observers (AAVSO)
Sat, 02/15/2014 - 03:53
Looking at the light curve of UV Per for the past year shows two distinct brightness levels for this star when it is in quiescence, V~16.0 and V~17.5 to 18.0. I suspect that some CCD observers are measuring the 16.3V comp star 8" away from UV Per. Observers who have reported UV Per at V~16.0 in quiescence, should re-examine their images to see if the correct object was measured.
Bob
Hi Bob,
We think you're right. I added a note to VSX about the close companion as a warning that will appear in the footer of all AAVSO charts of UV Per plotted on the chart plotter. Arne has asked Sara to contact observers who may have submitted combined magnitudes or observations of the wrong star. Thanks for the helpful feedback!
Mike Simonsen
AAVSO
Hello
I agree also. Thanks to observers STR, BOA, PKV and MRV who got it right, allowing this comparison to show that there might be a problem. I like the note being added to VSX which will appear on all charts.
Thanks to HQ staff for doing the complete job on this one. Hopefully the observers with bright measurements will be able to reprocess their data and make a really nice quienscent light curve for this object.
Gary
Thank you for bringing this to our attention, Bob. The observers we suspect were including the nearby companion have been contacted and the data are already looking much better.
-Sara
I see the same thing with MR UMa. The chart clearly states that a 15.88V star is located a mere 5 arc seconds south of the variable, yet we see two tier data in the database - low 15 CCD measures from some observers and negative (<17.0) from others.
I'm glad to hear that the UV Per observers responsible for the bright quiescent magnitudes have been contacted and that the data is now looking better. I wonder if the MR UMa guys could be made aware of the close comp. star too - or just asked by HQ to pay a little more attention to the notes on the chart.
Gary
Hello Gary
Thanks for pointing this out. Checked my data, and looks like I dodged this bullet--just lucky I think. I do remember something that might help other observers. I remember that Maxim sometimes jumps to the brighter companion, even though one has designated it correctly in the first image. Its happened to me in the past, but I don't remember if this is the object in question. I also believe that VPHOT will also jump to the brighter companion.
In Maxim, I go thru and look at the anulus for each image, and make sure that it has not jumped off track. I think you can do the same in VPHOT.
Gary
Thank you for pointing this out, Gary (actually both Gary's!).
Several observers have been contacted and asked to check their images.
Meanwhile if you have any further advice to offer on how best to observe this star, I'm sure it would be appreciated.
-Sara