Hello dear VS observers,
I’m currently coding a python app in order to automate some tasks.
Now, I’m implementing some automated queries on VSX.
What I have found, so far, is that, whaterver the query I tried, I get always the same huge list of stars : 9999 stars, troncated to 5000.
My goal is to ask vsx to search within a radius of 1 to 300’’ to a position, most currently around 10’'.
What I’ve got is totally erroneous results.
See attached screenshots.
The queries I did, for example are :
https://www.aavso.org/vsx/index.php?view=results.get&coords=01+16+34.45+-15+34+12.50&size=300&unit=2&geom=c&order=9&class=0,1,2,3
https://www.aavso.org/vsx/index.php?view=results.get&coords=01+16+34.45+-15+34+12.50&size=30&unit=3&geom=c&order=9&class=0,1,2,3
or :
https://www.aavso.org/vsx/index.php?view=results.get&coords=01+42+18.45+34+16+22.50&size=300&unit=3&geom=c&order=9&class=0,1,2,3
I can’t find where I’m wrong. I changed the value of the radius, and the unit from 2 to 3, and even the area in the sky with different coordinate.
Plus, off course, the server’s answer is very slow, for such a large number of stars.
The downloaded corresponding .csv files reflects the situation.
Any help/advice/suggestion would be very much appreciated.
Thanks in advance,
Christophe
Hello there,
Some news about this queries.
I finally stopped working on the web query method. Instead, I downloaded a .dat version of the vsx on CDS/Vizier, and adapted the code to a query on the local file. It worked.
So … remains only the mystery. Was my coded request url wrong, or an issue with the vsx server … hummmm. Don’t know.
Thanks for reading,
Clear skies,
christophe
1 Like
Hi Chris,
From what I recall, there were some changes to VSX’s Cone Search algorithm that could be causing the issue you noted. I’ll chat with our development team about it to see if we can track it down.
Generally speaking, if someone is going to be running many queries against VSX, we prefer that they use a local instance of the database instead of the live server. Now that the database has over 9.75 million objects, queries that scan the entire table (like cone searches) are incredibly expensive for us to support.
Please note that we will be replacing VSX and the VSX API sometime later this year. If you would like to receive notifications about this, please subscribe to the developer mailing list in your profile.
Kind regards,
Brian
Hello Brian,
I understand you position about the vsx server workload, with so many request every day.
What I have learned since my first message here, is that quering the vsx DB locally can be down very quickly : the mean time for returning several hundred of stars around a position (typically radius = 600") can be down in about 0.005 sec.
But this need some coding skill, which every potential vsx user don’t have.
May I suggest that AAVSO distribute (freely available) a small interface to be installed locally, together with the free DB available on the CDS ftp, and a good advertisement campaign on the vsx webpage (something like "The full VSX data on your machine, faster and easier than the web app). I think it could decrease the workload on the server, for a fraction of the price of a new server 
I would be pleased to receive news about the developpment of the vsx. I will subscribe to the suggested mailing list. Thanks for that idea.
Clear skies,
Christophe
