How reliable is the AAVSO VSP?

[David Bennett]

I plotted a star chart from the AAVSO variable star plotter to help me identify Tres-1 (V0672-Lyr) and I noticed there is a star clearly indicated on the star chart about 3 arc minutes from V0672-Lyr that is not visible in any of my several hundred images taken that night. This star is also not visible in the AladinLite viewer in Simbad.

Is this something to get excited about or do errors exist in the AAVSO database? 

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[Dr Paul Leyland]

I have found errors in VSP. A few people with whom I have corresponded have also found errors.  Some objects are missing from the VSP; some non-existent objects are included.

Unfortunately it appears that it may be difficult to get errors corrected.

How excited to get is a matter for you to decide. What I do is always to check with the MPC asteroid calculator and to compare with the DSS images available through Aladin. If something new passes both those tests, then I get excited and ask for confirmation. The last time this happened it turned out that the suspected transient was actually a ghost of a bright star.  The slightly embarrassing details can be found on my personal collection of images here on britastro.org.

[Gary Poyner]

I always find it useful to plot a DSS image from VSP, especially when comparing to images taken yourself.   The computer generated charts do contain the odd error (both bright and faint stars) which users should be aware of.

I use the VSP-DSS charts for both visual and CCD work.  I would advise you to do the same, or at least give it a try.

Good luck,

Gary

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