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AAVSO Exoplanet Report File Format

Version: 0.62
Release Date: Feb 12, 2018

This is one of the ASCII formats that the AAVSO accepts for uploading a file of variable star observations. Please use the WebObs File Upload page to upload your exoplanet data that has been formatted as described in this document.

 Visit the Software that exports to AAVSO format page to help format your observations.

The exoplanet format has two components: parameters and data, where the latter represents a series of measurements each of which contains the differential magnitude or relative flux difference between the exoplanet’s host star and one or more comparison stars.  Each component of the file is discussed in detail below.

Note that this format is different from the Extended File Format used for CCD observations in that an ‘observation’ is the whole file with its time-series of ‘measurements’. It’s one observation per file.


The Parameters are specified at the top of the file and are used to describe the measurement data that follows. Parameters must begin with a pound sign (#) at the start of the line. There are a number of specific parameters that we require to exist at the top of the file. Personal comments may also be added as long as they follow a pound sign (#). These comments will be ignored by the software and not loaded into the database. However, they will be retained when the complete file is stored in the AAVSO permanent archives. The format is case sensitive.

The required parameters:

  • #TYPE= Must be EXOPLANET for this format.
  • #OBSCODE= The official AAVSO Observer Code for the primary observer of the data submitted.
  • #SOFTWARE= Name and version of software used to create the observation. If it is private software, put some type of description here. For example: "#SOFTWARE=AIJ Version 2.2". Limit: 255 characters.
  • #DELIM= The delimiter used to separate fields in the Data section of the report. Select from the set:  comma (,) semi-colon(;), tab(tab), pipe(|), exclamation point(!), colon(:), slash(/) or (?). Note that if you want to use a tab, use the word "tab" instead of an actual tab character.
  • #DATE_TYPE= The type of time reference for the date/times used in the data section of the file. Times are midpoint of the observation. Note that data to a precision of ms is acceptable (8 decimal places). Valid values are:
    • JD_UTC: Julian Day (eg: 2454101.75634)
    • HJD_UTC: Heliocentric Julian Day
    • BJD_UTC: Barycentric Julian Day
    • BJD_TT: Barycentric Julian Day, Terrestrial Time
    • BJD_TDB: Barycentric Julian Day, Barycentric Dynamical Time
  • #OBSTYPE= The type of equipment used to make the measurements in the data file. It can be CCD or DSLR. If you are using a CMOS camera, code it as CCD. This file
  •  #STAR_NAME= Name of the host star that the exoplanet orbits.  This name should exist in the VSX database or be known in NASA’s MAST system. If it is not then you will need to include the RA/Dec/Epoch parameters listed below.
  • #RA= If the STAR_NAME is not known by computer query then you are required to input the coordinate information here. But if the star is known then these coordinate entries will be ignored. Use sexigesimal or decimal degrees.
  • #DEC= as above
  • #EPOCH= The epoch of the coordinates entered above. (e.g., J2000)
  • #EXOPLANET_NAME= The name of the exoplanet. Ideally, this should be the Star Name with a small letter suffix of “b”, “c”, “d”, etc. However, it can also be the arbitrary name of an exoplanet used in an exoplanet campaign.
  • #BINNING= 1x1, 2x2, 3x3, or 4x4.
  • #EXPOSURE_TIME= The exposure time in seconds.
  • #FILTER= Valid AAVSO filter designation. Must be a ShortName from the list created by . Some exoplanet observations may be using CBB (Clear Blue Blocking, the so-called Exoplanet Filter). If not using a filter (Clear) use the designation CV.
  • #DETREND_PARAMETERS= A comma separated list naming the detrend parameters whose data is included in the following data records. You can 0 to 4 names here and then must have 0 to 4 columns at the end of your data records below to hold this data.
  • #MEASUREMENT_TYPE= An indication of how each measurement in the data records should be interpreted (“Rflux” indicates relative flux, “Dmag” indicates differential magnitude, “Rnflux” indicates normalized relative flux)

Optional parameters:

  • #SECONDARY_OBSCODES= A comma separated list of the official AAVSO Observer Codes of secondary observers associated with this observation.
  • #PRIORS= Free form field to note of the “priors” used for modeling this exoplanet transit.
  • #RESULTS= Free form field to note the observations results, including, for example,           (Rp/R*)^2, a/R*, Tc, and inclination.
  • #NOTES= Freeform description of this observation

If you want to put a blank line between your parameter records and your data records, be sure to comment the line out with the pound sign (#); WebObs will not accept a file with blank lines that are not commented out.


After the parameters come the actual observation measurements. There should be one measurement per line and the fields should be separated by the same character that is defined in the DELIM parameter field. If you do not have data for one of the optional fields, you must put "na" or “n/a”as a place holder. The list of fields are:

  • DATE: The date of the measurement, of the type specified in the header DATE parameter.
  • DIFFERENCE: The differential magnitude or the relative flux difference for this measurement. Decimal field(12, 6)
  • ERROR: Photometric uncertainty associated with the DIFFERENCE value. If not available put "na". Decimal field(12, 6)
  • DETREND_1: The first of up to 4 detrend parameters as named in the header DETREND_PARAMETERS field. Decimal field(12, 6)
  • DETREND_2:
  • DETREND_3: Add detrend columns only if they are named in the header.
  • DETREND_4:




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