AAVSO charts with no comparison stars

American Association of Variable Star Observers (AAVSO)
Fri, 10/20/2023 - 04:24

Hello everyone,

I was exploring the VSX database last night looking for potentially interesting stars to monitor that would be accessible to my equipment and limited visibility window off my back southern-facing patio.  I came across SZ Aqr, a type LC variable 8.4-10.4V with a period of 141.93 days.   I generated chart X34493PG (FOV=2.0  / mag limit 12.0) but no comparison star magnitudes are listed. 

For fun, I configured the chart to show VSX variables in the field of view then looked up various other star magnitudes on Stellarium.  (A few of the brighter stars have HD identifiers.)  I assume that there are other considerations for selecting appropriate comparison stars, such as color index, that I wasn't accounting for.   I went ahead and estimated a 9.1 magnitude.  Would AAVSO want such observations, and if so, how to indicate comparison stars with no obvious identifier?  (RA/Dec coordinates?).  Or perhaps the data so suspect as to be of limited scientific value.   I won't take it personally if that's the case.  :-)


John Rachlin (RJOJ)

Hi John...

Hi John. If you are logged in with your account, you can try to ask for comparison stars. There is a team to help with it. The VSX account is different from your AAVSO login.

I hope it helps you in some way.

American Association of Variable Star Observers (AAVSO)
Requesting Comparison Stars

Thank you Cledison.  I did go ahead and create a vsx account.  I think the information I was looking for is here:


(I didn't realize that the link labeled  "Request a Sequence" on the Variable Star Plotter main page refers to requesting comparison stars.   Beginner mistake.  :-)  )

I'll go ahead and submit the request to the compstars team.  FYI, SZ Aqr currently has just 15 observations by 3 observers dating from 1972-2013.  The lack of observations is probably due to its southerly declination and the lack of comparison stars.  Historical fun fact: SZ Aqr was discovered by Henrietta Leavitt in 1913.