Search AAVSOnet Epoch Photometry Database


The AAVSOnet Epoch Photometry Database consists of robotic pipeline photometry from older images taken by AAVSOnet telescopes.  The major contribution is from the Bright Star Monitor network, with lesser contributions from other network telescopes.  Some of these other telescopes may have only been part of the network for a few years.

The Bright Star Monitor (BSM) Epoch Photometry Database (EPD) v3.0 (released October 22, 2015) contains more than 66 million photometric observation datasets of more than one million stars during the period of time between October 14, 2012 to September 30, 2015.  The stars covered, both variable and constant, lie within fields observed with the Bright Star Monitor network.  Every frame taken with the five active BSM systems (in both the northern and southern hemispheres) is photometered during processing, and magnitudes of every star from every available filter are extracted.  These individual sets of measurements are also stamped with the time of observation, and so the full database represents a time series for each of these one million stars.

Because the BSM telescopes observe specific targets rather than the entire sky, this catalog is not complete across the entire sky.  Where coverage exists it is also not uniform in time; some stars may have substantial data, while others may only have one or two observations.  The observations are also mixed in quality, and are not uniformly photometric.  We include all observations, but individual data points are flagged according to whether they are (a) photometric and (b) saturated.  Observations are presented as groups with an individual "dataset" consisting of magnitudes in all available filters taken at nearly the same time.

The Wright 28 (W28) dataset is from a 28cm telescope at Astrokolhoz Observatory that was only active for three years.  It primarily obtained time series photometry of stars and so covered many fewer targets than did the BSM network.

The Krajci 35 (K35) dataset is from a 35cm telescope at Astrokolhoz Observatory that was only active for a little over one year.  It obtained pointed multiband photometry of mostly CVs, along with transient discoveries.

Data and Search Description

Depending upon the format you request the data in, the complete record for each observation consists of 38 separate fields in the following order:

  1. Distance: arcseconds from search coordinates (or VSX coordinates for star name searches). [Note: this field is not a part of the AAVSOnet EPD -- it is calculated based upon your target coordinates.]
  2. RA: J2000 right ascension in degrees.
  3. RAerr: position error in arcseconds.
  4. Dec.: J2000 declination in degrees.
  5. Dec.err: position error in arcseconds.
  6. Red. HJD: Heliocentric Julian Date - 2400000.
  7. Airmass: airmass of object at time of exposure.
  8. Vphot: V magnitude quality flag: 0 if photometric, 1 if non-photometric.
  9. BVphot: B-V magnitude quality flag.
  10. UBphot: U-B magnitude quality flag.
  11. VRphot: V-R magnitude quality flag.
  12. RIphot: R-I magnitude quality flag.
  13. VIphot: V-I magnitude quality flag.
  14. Usat: U magnitude saturation flag: 0 if not saturated, 1 if saturated.
  15. Bsat: B magnitude saturation flag.
  16. Vsat: V magnitude saturation flag.
  17. Rsat: R magnitude saturation flag.
  18. Isat: I magnitude saturation flag.
  19. Vmag: Transformed Johnson V magnitude.
  20. eVmag: error in V magnitude.
  21. BVmag: Johnson B-V color.
  22. eBVmag: error in B-V color.
  23. UBmag: Johnson U-B color.
  24. eUBmag: error in U-B color.
  25. VRmag: Johnson V - Cousins R color.
  26. eVRmag: error in V-R color.
  27. RImag: Cousins R-I color.
  28. eRImag: error in R-I color.
  29. VImag: Johnson V - Cousins I color.
  30. eVImag: error in V-I color.
  31. Vzero: V-band zero point correction.
  32. BVzero: B-V zero point correction.
  33. UBzero: U-B zero point correction.
  34. VRzero: V-R zero point correction.
  35. RIzero: R-I zero point correction.
  36. VIzero: V-I zero point correction.
  37. field ID: 11-character AAVSOnet field designator
  38. Source: 2-character designator which indicates which telescope was used
    (28=BSM_NM, 37=BSM_S, 40=BSM_HAMREN, 41=BSM_BERRY, 45=BSM_HQ, 30=W28, 34=K35)

Data may be extracted in two ways: individual variables by star name, or sky positions.

  1. Individual variables:  If you want data for a specific variable star that has a name in the AAVSO Variable Star Index, enter that name in the "Star name:" box.  This will trigger a search of all data within a 5-arcsecond radius of the VSX position.
  2. Sky positions: If you want to search data for a field or a non-variable star, enter coordinates into the RA and Declination boxes (sexagesimal or decimal format), and choose an appropriate search radius.  Note that radial searches are limited to 3 degrees at this time.  The resulting data will consist of all magnitudes sorted by RHJD; for field searches, that means that multiple stars will be mixed together into a single data file, and will need to be separated manually.  To search for data for a single star, we suggest using a 5-arcsecond (0.0014-degree) radius. Note: to use this feature, you must erase any text in the Star Name box.

Data output may be one of three formats: HTML, CSV, or SIMPLE.

  1. HTML: data are output to your browser, and appear as an HTML table (useful for visual inspection)
  2. CSV: data are output to a file in ASCII CSV (comma-separated variable) format.  You will be prompted to open or save a file; this may try to launch your spreadsheet software upon opening.
  3. SIMPLE: this is a highly truncated CSV format that outputs only three fields: Reduced HJD, V magnitude (only), and V magnitude error (only).  This is suitable for quick inspection and analysis, but does not provide any information about other bandpasses besides V or photometric quality.

Data Usage

These data are for the exclusive use of AAVSO Members.  They may not be extracted and served on any other website.  AAVSO Members are free to mine these data and use them in their own research or as supporting data for VSX submissions, but they may not be submitted to the AID as observations.  Our intention is to keep AAVSOnet Epoch Photometry as a database separate from member-contributed data; any data submitted to the AID from these tables may be rejected by AAVSO staff.  When using these data in any publication or presentation, please cite them as AAVSOnet Epoch Photometry Data (v1.0).


Star name: Note: Star name supercedes coordinates below
RA: Decl.: Radius (degrees)
RHJD: (HJD-2400000) Min: Max:
Magnitude Range (V): Bright V: Faint V:
Include non-photometric data: Yes No
HTML output
CSV output
SIMPLE (CSV) output


Note: Another way to use this data is through use of VStar and its AAVSOnet epoch photometry observation source plug-in. This will not require you to download a data file, but access it through VStar directly.



The AAVSOnet and its Epoch Photometry Database were made possible through the generous contributions of James Bedient, Donn Starkey, Doug Welch, Tom Krajci, Peter Nelson, Bill Stein, Greg Bolt, Bob Stine, Mike Linnolt, Richard Berry, David Benn, John Gross, Doug George (Cyanogen), Bob Denny (DC3 Dreams), and the Santa Barbara Instrument Group (SBIG).