API's to AAVSO resources

Hi George,

Thanks for compiling this :). I started building a small app, and this is exactly the info that I needed. And I got it vithout even asking.

Alex.

This will give you the variable star coordinates, the size of the FOV and the photometry table - albeit in an HTML document:

http://www.aavso.org/cgi-bin/vsp.pl?chartid=13221ASP&ccdtable=on

Alex.

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The link above will list also a color index (B-V). Will that be OK?

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Just wondered, the link you initially posted ( http://www.aavso.org/cgi-bin/vsp.pl?chartid=13221ASP&delimited=yes ) will list B and V magnitudes. You can also simply subtract them to get your color index. So the only real advantage for the one I posted is that it also lists the coordinates of the variable. 

Hi George

I've written a VSX VOTable reader in Java for VStar. It's not currently used but I'll switch to it at some stage. It's here if you want to have a look:

http://sourceforge.net/p/vstar/code/HEAD/tree/trunk/src/org/aavso/tools/vstar/input/database/VSXWebServiceVOTableStarNameAndAUIDSource.java

This would certainly give you what you need (spectral types, coordinates).

If you want help translating this to Python, let me know.

David

For those who are going to read and parse the XML output of the new VSP API by scanning, there are a few wrinkles to keep in mind.

This is repost; it really belongs in this thread.

You need to keep track of
(1) what level you are in the XML stream and
(2) that you are not guarenteed the order of elements you find within a level.

For instance, from https://www.aavso.org/apps/vsp/api/chart/X15296BK/?format=xml
<list-item>
   <band>V</band>
   <mag>11.305</mag>
   <error>0.032</error>
</list-item>
What if band comes after the mag and error? It doesn't here, but it could by XML rules. You wouldn't know which filter the mag belongs to until you finish that level defined by the list-item start and stop.

Further, some tagnames appear at multiple levels. Eg, "auid" appears at the root level, the star's auid, and in the phtometry level, the auid's of the comp stars. Same with "ra" and "dec"

XML scanners will offer the elements/tags it finds in sequence, offering tagType, tagName and tagContent fjor each. tagTypes are  tagStart, tagContent and tagEnd. tagNames will be the string in <>'s (eg "band"). And tagContent will be the value (eg "V")

The way I am doing it is to watch for a tagStart with the tagName of "list-item". That tells me I've moved up one level. Level 1 is photometry and level 2 is bands. While in a level I look for tagContent and collect the expected data for that level, but I don't do anything with it until I see the tagEnd, tagName of "list-item". Then I know its safe to act on the collected data, in this case assigning the comp's V mag and error.

I've been going through this coding for TA, PhotomCap and VPhot. Ignoring these subtleties could cause very hard to debug errors in your data.

Cheers
George

Hello all,

I'm not a programmer, but I have had some contacts with VOTable. I have found it to be a Good Thing when we are talking about self-descriptive data formats. And because it is used very widely in professional astronomy, there are usable standard-like guidelines or definitions available, e.g the following one:

http://www.ivoa.net/documents/VOTable/20130920/REC-VOTable-1.3-20130920.html

If/when AAVSO API(s) are compatible with such definitions, there are plenty of tools that would really benefit. Isn't it a final goal to have AAVSO resources linkable to Virtual Observatory?

George, IMHO Simbad is The Source (hehe.. many would argue for sure ;-) ). AUID is just a name (as it looks to me) like one of the tens for some stars (visible e.g. in Simbad). While it is more convenient to use names in manual way (well, "I used comp star 329.354625, +44.235031" ;-) ...), decent (accurate and precise enough to be "unique") coordinates are IMHO much more general way to describe a star. Fortunately, coordinates are getting better and better. When I'm doing photometry of open clusters or just generally variable stars (not for AAVSO), I use always WCS+coordinates to identify my (or all stars in FOV) targets and that works just fine. Coordinates just happen to be tied to names in UCAC#, 2MASS, USNIO, HD etc etc catalogues.. When one wants additional data from Simbad, AUID could be solved to coordinates (using e.g. an AAVSO API?) and using those coordinates, sending required query to Simbad to retrieve some or many useful info bits.

Just a remark: spectral class in Simbad can not be trusted always. That may change in/after Gaia era (Gaia provides also plenty of spectroscopy) but probably is not going to happen for bright(er) stars and not before 5+(?) years. At the moment, I personally believe that having good photometry (APASS and Simbad for brighter stars?) in few filters would be (much) better approach.

Best wishes,
Tõnis

Hi all,

Is there a better way to programatically access APASS data than with the link below? 
https://www.aavso.org/cgi-bin/apass_download.pl?ra=271.4032917&dec=-44…

regards,
Mike

"better" is such a dangerous thing to wave in front of programmers.

I use the python astroquery library to access APASS from ViZieR.  If you think this might be better for you, let me know and I'll send you some sample code.

Cliff

Hi,

I'm new to AAVSO and Photometry of variables and have built an app that  takes my observation data, enters it in a DB and generate light curves as well as an output file for AAVSO entry. 

I'm able to get finder charts and associated photometry table to help me find the star in question as well as comparison stars.

What  I was wondering is there an API  that  would give me a one line output (CSV?)  of the chart table that  matches the star label  number  that's found on the star chart? I don't know how this table is generated and my request may not be possible.

At the present I have my program ask for the Table for a specific variable star and then extract the info I want out of the HTML page that  is returned. The process is a bit of a kludge. A simple CSV file with the data in it would be great.

  When I started out learning about  Variable Star Observation, last month, I downloaded the VSX data from the web page as a CSV file and dumped it into my SQL DB. I noticed today that there is an option to extract last weeks changes from the VSX DB. I'm wondering if there is an API that  I could use to get the VSX data in a xml or csv form directly rather than going to the site manually and pulling the data.  If this were possible it would make it easy to keep my DB up to date. 

Thanks

Nor

Hi George,

I've noticed that query to VSX gives incorrect min. passband for some stars. For example:

https://www.aavso.org/vsx/index.php?view=query.votable&ident=pmak+v33

gives MinMagPassband = V. Actually, it is an amplitude and the passband is TESS (nonstandard).

Best regards,

Max

The VSX API is not "official" yet, but here is some documentation (some of it may be changed in the future).  There are two versions: object and list.  The general URL is:

https://www.aavso.org/vsx/index.php?view=api.object&param1=n&param2...

https://www.aavso.org/vsx/index.php?view=api.list&param=n&param2...

The output format for both API's is given in https://www.aavso.org/vsx/index.php?view=api.xsd, unless specific formating parameters are used, see below.

The object API has one specific parameter: ident, the name of the object(s) requested (this may be a list delimited by commas).  These may be aliases, AUID's.  The name need not be spelled exactly as in VSX (e.g. spaces are not necessary, no distinction between V999 and V0999 ...).  Wildcard characters are not interpreted.
Note: a space in a URL is denoted as a plus sign (+), the + in the name (e.g. when the name contains the position of the object) needs to be URL encoded as %2B.

Example: https://www.aavso.org/vsx/index.php?view=api.object&ident=HIP39986

The list API has several specific parameters:

- fromra=, tora=, fromdec=, todec=: limiting values of right ascension and declination (epoch 2000) in degrees
- ra=, dec=, radius=: search for objects in an area with given right ascension and declination (epoch 2000) as center and radius in degrees
- tomag=: brightest magnitude needs to be brighter than the value given

Parameters used in both API's:
- att: use attributes instead of individual elements in the xml
- format=json: output format is json, not xml
- auid: only list objects with an AUID

Patrick

Graet information. Keep sharing!

I've been away for some time and think that things may have changed since I was here last. 
I have built an app that  allows me to generate a light curves and creates an output file to be uploaded  to AAVSO.

I thought that I would start this up again but am getting an 500 server error when trying to get the XML data for a specific star.

Here is the String I sent to aavso to get the data.
https://www.aavso.org/apps/vsp/api/chart/?star=000-BBH-936&fov=30&maglimit=14.5&format=xml&resolution=150&dss=on&north=up&east=left

This format used to work back in 2018-2019. Is there somthing wrong with my request or is the problem on the other end?

Thanks

 Nor

This is the wrong place for this info. Rather: all AAVSO API information should be in a one single, prominent page on the AAVSO website. Perpetually kept up to date, complete to the last API, simple in format, and linked to on the AAVSO *front* page (if not at the bottom of every page). It's not like the website doesn't have plenty of blinding white space to use.

Efforts to answer users' questions here are much appreciated, and questions will persist. But questions are coming up on info that people could find for themselves. The Forum, with its timeline layout and its keeping of old, now-invalid info, is an *extremely* inefficient place to try to offer one simple display of all currently valid API information.