Exactly one year ago we were celebrating our 1,000,000 milestone. In that ocasion, 650,000 objects from the OGLE database had been imported to VSX.
Now we can announce that VSX has doubled its number of records in one year!
Last friday we finished adding ~665,000 objects from the the Zwicky Transient Facility (ZTF) Catalog of Periodic Variable Stars. Due to this update, the number of VSX records -on September 27, 2020- has grown to 2,103,831.
The ZTF catalog is not only a list of new variables but also an impressive resource that has been used to update the information on 114,000 variable stars. This includes several thousands of new identifications! (which means that thousands of stars were wrongly identified with a neighbour in VSX). With a resolution of 2" and a positional accuracy of a fraction of an arcsecond, the ZTF data are especially good for such a correction job.
Those results will see the public light in the upcoming weeks.
I wonder when we will reach the 3,000,000 object milestone!
But the answer may lie not so far ahead. Having improved positions for so many stars also allows much easier handling of large datasets that aren't of so high quality as ZTF is. ATLAS and Gaia variables (and another list of OGLE stars) are the next major lists in the works.
I would like to thank Patrick Wils for his work with VSX behind the scenes.
And I encourage you to participate in the VSX continuous update process by sending revisions or letting us know about any mistake that you find.
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we don't assign AUIDs for the objects we add to VSX from these major lists.
But if somebody wants to observe them and the object has an amplitude enough to be detected safely with their set up, an AUID request can be submitted through VSX and after checking the star parameters and identification we do assign it.
Sometimes stars may have wrong IDs or very small amplitudes, that's why we took the safest approach to avoid receiving observations that could have problems or be useless.
The particular case of the ZTF list is different, the survey has a very good resolution (better than 2") so IDs are correct most of the time, and amplitudes are larger than 0.03 mag. unlike Kepler, KELT, TESS, etc. that have a poor resolution (there may be blends up to 1 arc minute away) and objects with amplitudes of only milimagnitudes.
I had a friend that told me "why do you observe stars off of the VSX? There is nothing new to be learned there!" Often, especially when you have to apply for an AUID, these stars don't match the survey information. The surveys are not always right so doing photometry on these stars is still important and helpful. Had several overcontact binaries that had entirely different periods from what the survey that found them said. Really appreciate the VSX team, especially the comp star group.
You are totally right. The number of wrong classifications and elements in VSX grows along with the number of objects because survey data have limitations. So keep those observations coming. And try VSX revisions if you want to help us correct the wrong information :)