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Gustav Holmberg

I am interested in analysing data from ASAS-SN but have not been able to import data to Vstar. Any ideas?


CTX's picture
All Sky Automated Survey

Of course, after the other responses, I realized that I mis-read the question..... geezzz, but glad it all worked out for Gustav.

To the best of my knowledge “ASAS-SN” references the All Sky Automated Survey for SuperNovae (aka “ASAS-SN).

Typical Transiet object designations are ASASSN-YRxx where YR is the two digit year ending and xx is a sequential alpha naming progression.  If you check the Transients web page the current listing, at the top of the page is for ASASSN-17qn, as an example:

Data Based objects of the AAVSO can always be checked via the VSX.  If it does not appear there then it is not in the data base and there is a method therein to request inclusion:

Tim Crawford, CTX

Sequence Team

David Benn
David Benn's picture
Not to worry :)

No worries Tim. Useful information anyway. laugh


Gustav Holmberg
I was thinking of analysing

I was thinking of analysing data like this, for example, using Vstar. There's an export option using csv format, but when I try to load that into Vstar it doesn't work.


WGR's picture
CSV data to Vstar

Hello Gustav

I export data to Vstar very often.  I believe that Vstar only wants a JD and a magnitude.  If you are exporting more that this, it might be the problem.



David Benn
David Benn's picture
ASAS-SN observation source plug-in

Hi all

Thanks for your input Gary and Tim.

Gustav, after reading your post, I wrote a ASAS-SN observation source plug-in while on my daily bus commute today and finished/tested it this evening after work (it's almost midnight here in South Australia). cool

I've attached a zip file containing all current plug-ins plus the new ASAS-SN plugin. You can install it by creating a temporary directory, unzipping the zip file into that directory and either:

I've carried out minimal testing so far: on the dataset you pointed to above and a random one I searched for and downloaded on the ASAS-SN web page.

I'm handling the 5-sigma limit (see pages 4, 5 of referenced on by using a separate series for such observations. In addition, any observation for which the mag and mag_err are both 99.99, the plug-in ignores. Let me know if you think different series colours should be used. The main series is V as I understand it, hence the colour.

Once more testing (e.g. by you and others) has been carried out and a simple how-to guide has been written, the plug-in will be made available in the AAVSO plug-in repository. 

Please give it a try and let me know how it goes. A new item will appear in the File menu.


Gustav Holmberg
It works like a charm!

It works! I installed the new batch of plugins in a temporary directory, pointed to it in preferences/plugin-in settings/ and installed the ASAS-SN plugin. Then I have been able to load ASAS-SN datasets in Vstar.

Many thanks for the quick response, making the already great Vstar an even better tool for variable star astronomy. Great!


David Benn
David Benn's picture

Hi Gustav

That’s excellent and thanks for your kind words. :)

Let me know if you see any problems.

If you want to use the standard online plugin library again, just click the Set Defaults in the plug-in settings preferences pane.


Textor67's picture
Problem with data import

Dear David and Cliff, I have the ASAS-SN plugin installed and vstar could detect it. However, I get an error message "No observations for the specified period" when trying to import data with it. Did I do something wrong?

many Greetings


Textor67's picture
Thomas' Log

Jan 15, 2019 9:30:18 PM showErrorDialog
SCHWERWIEGEND: No observations for the specified period.
Jan 15, 2019 9:33:38 PM showErrorDialog
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David Benn
David Benn's picture

Hi Thomas

Sebastian Otero has mentioned to me that there was recently a change to the format of the data.

I'll look at this and get back to you.

Can you please tell me which dataset you were downloading so I can replicate the problem?



Textor67's picture
ASAS-SN data

Dear David, I'll send you a record of R Vir (lc123451.dat)
Many Thanks


#HJD          Cam  mag   mag_err  flux (mJy)   flux_err (mJy)
#              (5 sigma limits)
#Cam: Hawaii=abcd Chile1=defg Chile2=ijkl SAAO=mnop Texas=qrst
2456619.12177    bd    8.26    0.1    1905.89    175.342
2456625.11361    bd    7.973    0.1    2480.752    228.229
2456641.0544    bd    7.213    0.1    4996.188    459.649
2456657.0102    bd    7.272    0.1    4731.254    435.275
2456674.98675    bd    8.651    0.0    1328.892    0.0
2456700.91447    bd    10.105    0.1    348.335    32.047
2456736.81007    bd    10.662    0.1    208.577    19.189
2456740.80244    bd    10.385    0.1    268.978    24.746
2456742.02493    bd    9.988    0.1    388.069    35.702
2456766.98741    bd    8.681    0.0    1292.954    0.0
2456783.8463    bd    7.811    0.1    2881.202    265.071
2456794.8418    bd    7.477    0.1    3920.002    360.64
2456797.85195    bd    7.453    0.1    4004.402    368.405
2456798.84611    bd    7.48    0.1    3907.175    359.46
2456800.83777    bd    7.552    0.1    3655.458    336.302
2456801.8342    bd    7.593    0.1    3521.404    323.969
2456802.83155    bd    7.594    0.1    3517.446    323.605
2456804.83228    bd    7.696    0.1    3202.011    294.585
2456806.83858    bd    7.777    0.1    2971.108    273.342
2456807.83887    bd    7.849    0.1    2781.75    255.921
2456809.82044    bd    7.919    0.1    2607.796    239.917
2456810.8205    bd    7.989    0.1    2446.299    225.06
2456811.77189    bd    8.03    0.1    2355.018    216.662
2456812.79803    bd    8.125    0.1    2157.789    198.517
2456818.80544    bd    8.604    0.1    1388.023    127.698
2456820.80298    bd    8.784    0.0    1176.07    0.0
2456822.80602    bd    8.931    0.1    1027.108    94.494
2456823.81351    bd    9.023    0.1    943.099    86.765
2456824.80571    bd    9.129    0.1    855.835    78.737
2456826.79396    bd    9.249    0.1    765.803    70.454
2456827.79648    bd    9.367    0.1    687.373    63.238
2456828.80164    bd    9.428    0.1    649.527    59.756
2456829.7973    bd    9.535    0.1    588.951    54.183
2456830.79626    bd    9.592    0.1    558.491    51.381
2456832.78709    bd    9.683    0.1    513.822    47.272
2456835.77955    bd    9.937    0.1    406.395    37.388
2456971.14698    bd    9.112    0.1    869.544    79.998
2456972.14675    bd    9.201    0.1    800.536    73.649
2456987.12835    bd    10.21    0.1    316.205    29.091
2456991.1203    bd    10.622    0.1    216.418    19.91
2456993.11768    bd    10.908    0.1    166.297    15.299
2456998.10937    bd    11.201    0.1    126.898    11.675
2457000.10906    bd    11.535    0.1    93.275    8.581
2457001.10363    bd    11.681    0.1    81.542    7.502
2457002.09255    bd    11.652    0.1    83.806    7.71
2457011.1599    bd    12.559    0.1    36.337    3.343
2457018.10966    bd    12.73    0.1    31.037    2.855
2457021.07728    bd    13.127    0.1    21.525    1.98

Sebastian Otero
Sebastian Otero's picture
Two types of data pages

There are two different types of outputs with different columns. Those results already computed for known variables in V band and those that are computed after request including V and g observations. 

I think that two plugins will have to be made...




V and g'

Also, it's worth to mention there's a glitch related to latest data. Measurements made with camera that have a capital letter (eg. bG, bH) are marked as V, but in reality these are in g'. It has been there for a while and still hasn't been fixed.


Gabriel Murawski

David Benn
David Benn's picture
Two formats?

Hi all

So, the example dataset Thomas shows is ceertainly different from one I saw a few days ago which contains, for example, a V on the end of each row. I haven't spent any time looking at other differences yet.

A couple of days ago I requested R Vir data and got this page:

The Download Data link gives me data in the same format as Thomas's. How does one obtain the new format?


Sebastian Otero
Sebastian Otero's picture
ASAS-SN data

You can get the processed data for the ASAS-SN variables from the links like you sent but that is not trustable and a lot of observations will be missing.

#HJD  Cam  mag   mag_err  flux (mJy)   flux_err (mJy)

2456619.12177  bd  8.26 0.1  1905.89  175.342

Only V data are displayed.

Always select the ASAS-SN Sky Patrol link from VSX and choose the option "I want to recompute this light curve" (in the case of known variables) so all the data are retrieved.
If the star is not a known variable, always enter 2800 or so in the Enter number of days to go back field.

Observations are both in V and in Sloan g.
V observations stopped in december so now we only have g data.

First line of results:
HJD  UT Date   Camera  Filter     FWHM  Limit Mag Mag Error  Flux (mJy)     Flux Error                                
2455955.11866  2012-01-28.6157059     ba  V  2.00 14.886     9.453 0.002  634.872 1.262

As you see the output format is different and the data start at a differente date.

HOWEVER: you haven't chosen a good example. ASAS-SN data brighter than V ~10 are saturated. It is weird that the light curve looks so well. Actually, I don't understand it.


David Benn
David Benn's picture
Second ASAS-SN plugin

Thanks Sebastian.

From what you've said, we may need a second plugin. Any thoughts about what this should be called as opposed to ASAS-SN?


ASAS-SN Data formats

Hi Sebastian,

I'm curious as to why you label that data "not trustable", the bulk of our work is done with image subtraction photometry.

For clarification, the light curves available on the Variable Stars Database and the Sky Patrol are produced differently.

We use image subtraction photometry on co-added images (3 epochs per co-added image) to produce light curves for the variable stars and photometry databases. The "missing observations" arise from this process of co-addition. These were also generated for the V-band and newer g-band data (available through the real-time Sky Patrol) are not included in these light curves. We prefer to use image subtraction photometry for our projects involving variable stars since this works great in crowded regions and also goes deeper than the light curves available on the Sky Patrol.

The light curves generated through the Sky Patrol employ simple aperture photometry, and the exposures are not co-added (more observations, since all the exposures are listed). Both V and g-band observations are available through the Sky Patrol and the light curves are inherently more up-to-date.

It isn't fair to call either of these sources more trustable/reliable than the other --- they serve different purposes and have different characteristics. We actually prefer that you use the pre-computed light curves when available, unless you absolutely need real-time V+g band photometry. The Sky patrol is very popular and our servers can get overwhelmed quickly.

We are currently in the process of updating all the light curves on the variable stars database. The data format will also change as we do this update. When we have finalized the data format, I will make a post on this thread so that a plug-in can be developed. I would recommend naming the two plugins as follows:

ASASSN_APPHOT (Aperture photometry, Sky Patrol)

ASASSN_SUBPHOT (Image subtraction photometry, Variable Stars Database)

Best regards,

Textor67's picture
Names for the filters

Dear friends, I would use the name suggested by Tharindu for the two filters and add the letters "V" and "g".

Thank you for your help, Thomas











David Benn
David Benn's picture
Data formats, input

Thanks for all your comments everyone.

Tharindu, thanks for the suggested plugin break-up. So, we have Sky Patrol, Variable Stars Database, and Photometry Database.

VSX links to the first of these (Sky Patrol) which is V data. The format of this has changed in recent times, so the current (not formally released) plugin needs to be modified to handle this change. Correct?

Should I modify the exiting Sky Patrol plugin to conform to the current format? Or is that going to change again?

Other than this, I will wait for Tharindu's post re: data format changes.


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