This is one of two ASCII formats that the AAVSO accepts for variable star observations (the other format is the Official AAVSO Visual Format.) Observations in this format may be submitted to the AAVSO by uploading them via WebObs' Batch Upload Tool.

The Extended Format has two components: parameters and data.

The format is not case sensitive.

Parameters

Parameters always begin with a # at the start of the line. A certain number of keywords (parameters where an equals sign follows the first word) are required to be entered as parameters. The following five parameters are required to exist at the top of the submitted data file.

#TYPE=EXTENDED
#OBSCODE=
#SOFTWARE=
#DELIM=
#DATE=
#OBSTYPE=

• TYPE: Should always say Extended for this format.
• OBSCODE: The observer's code, previously assigned by the AAVSO.
• SOFTWARE: Name and version of software used to create the format. If it is private software, put some type of description here. For example: "SOFTWARE=Excel Spreadsheet by Gary Poyner."
• DELIM: The delimiter used to separate fields in the report. Any UNICODE ASCII character is acceptable, as long as it is not used in any field. We recommend comma (,).
• DATE: The format of the date used in the report. Times are midpoint of the observation. Convert all times from UT to one of the following formats (in order of preference):
  • JD: Julian Day (Ex: 2454101.7563)
  • HJD: Heliocentric Julian Day
  • EXCEL: the format created by Excel's NOW() function (Ex: 12/31/2007 12:59:59 a.m )
• OBSTYPE: This should be CCD or PEP. It defaults as CCD, so this is an optional field for CCD observers.

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 included when the complete file is stored in the AAVSO permanent archives.

The OBSCODE and DATE parameters may also be included elsewhere in the data. Our data processing software will read these parameters and will expect all following data to adhere to them. (For example, you can add "#OBSCODE=TST01" to the report and all subsequent observations will be attributed to observer TST01.)

Data

After the parameters come the actual variable star observations. There should be one observation per line and the fields should be separated by the same character that is defined in the DELIM comment field. Note: The A.I.D. field name is given in parenthesis where different.

The list of fields are:

• NAME: The object's identifier. It can be the AAVSO Designation, the AAVSO Name, the GCVS Name or the AAVSO Unique Identifier. The name is required.
• DATE: (JD or HJD) The date of the observation, in the format specified in the DATE comment field; a date is required.
• MAGNITUDE: The magnitude of the observation; a period is required. If the magnitude is a 'fainter than' magnitude prepend it with the "<" symbol.
• MAGERR: (uncertainty) The observation error; if not present, use "na".
• FILTER: (band) The filter used for the observation; a filter is required. Currently, this can be any of the following:
  • U: Johnson U
  • B: Johnson B
  • V: Johnson V
  • R: Cousins R
  • I: Cousins I
  • J: NIR 1.2 micron
  • H: NIR 1.6 micron
  • K: NIR 2.2 micron
  • TG: Green Filter
  • Z: Sloan Z
  • C: Unknown filter (discouraged - contact HQ and we will help you determine which filter code you should use)
  • CR: Clear (unfiltered), CCD with R-like response, R-band compstar magnitudes
  • CV: Clear (unfiltered), CCD with V-like response, V-band compstar magnitudes

• TRANS: (transformed) YES if transformed, NO if not; is required.
• MTYPE: Magnitude type; is required. DIF if differential, ABS if absolute. Differential requires the use of CNAME.
• CNAME (comp1_C): unique name for the comparison star, such as the chart label (though the AUID is preferred). If not present, use "na".
• CMAG: supplied magnitude of the comparison star. If not present, use "na".
• KNAME (comp2_K): unique name for the check star, AUID preferred. If not present, use "na".
• KMAG: measured magnitude of the check star. If not present, use "na".
• AIRMASS: airmass of observation. If not present, use "na".
• GROUP: grouping identifier. If not present, use "na". This should be a maximum of 5 characters.
• CHART: This should be the latest date you see anywhere on the chart, entered as YYMMDD. If you do not see a date, use the copyright year (Ex: "Copyright 2007" would be 070101). If no chart used, enter "na".
• NOTES: Comments or notes from the observer. This field has a maximum length of 100 characters. If no comments, use "na".

Here is a simple example:

#TYPE=EXTENDED
#OBSCODE=TST01
#SOFTWARE=IRAF 12.4
#DELIM=,
#DATE=JD
SS CYG,2450702.1234,11.135,0.003,V,NO,ABS,105,na,na,na,na,na,070613,This is a test

Here is a more complex example with both comp and check stars:

#TYPE=EXTENDED
#OBSCODE=TST01
#SOFTWARE=GCX 2.0
#DELIM=,
#DATE=JD
#OBSTYPE=CCD
#NAME,DATE,MAG,MERR,FILT,TRANS,MTYPE,CNAME,CMAG,KNAME,KMAG,AMASS,GROUP,CHART,NOTES
SS CYG,2450702.1234,11.235,0.003,B,NO,ABS,105,10.593,110,11.090,1.561,1,070613,na 
SS CYG,2450702.1254,11.135,0.003,V,NO,ABS,105,10.492,110,10.994,1.563,1,070613,na 
SS CYG,2450702.1274,11.035,0.003,R,NO,ABS,105,10.398,110,10.896,1.564,1,070613,na 
SS CYG,2450702.1294,10.935,0.003,I,NO,ABS,105,10.295,110,10.793,1.567,1,070613,na 

Note the existence of the #NAME,DATE... line in the above format. Since it is prepended with a #, it will be ignored by our software. Feel free to do this if it makes writing and reading the format easier for you.

Note: Ensemble photometry is permitted under this format. You need to pick one star (the check star) in addition to the target to be measured by the technique. This star's calculated magnitude should be put in the KMAG field, so that if the true magnitude of the check star is found to be different at a later date, a simple zeropoint offset can be added to your ensemble value. If ensemble is used, CNAME should be set to ENSEMBLE and CMAG should be set to "na", as shown below:

#TYPE=EXTENDED
#OBSCODE=TST01
#SOFTWARE=GCX 2.0
#DELIM=,
#DATE=JD
#NAME,DATE,MAG,MERR,FILT,TRANS,MTYPE,CNAME,CMAG,KNAME,KMAG,AMASS,GROUP,CHART,NOTES
SS CYG,2450702.1234,11.235,0.003,B,NO,ABS,ENSEMBLE,na,105,10.593,1.561,1,070613,na 
SS CYG,2450702.1254,11.135,0.003,V,NO,ABS,ENSEMBLE,na,105,10.492,1.563,1,070613,na 
SS CYG,2450702.1274,11.035,0.003,R,NO,ABS,ENSEMBLE,na,105,10.398,1.564,1,070613,na 
SS CYG,2450702.1294,10.935,0.003,I,NO,ABS,ENSEMBLE,na,105,10.295,1.567,1,070613,na 
SS CYG,2450702.2234,11.244,0.003,B,NO,ABS,ENSEMBLE,na,105,10.590,1.661,2,070613,na 
SS CYG,2450702.2254,11.166,0.003,V,NO,ABS,ENSEMBLE,na,105,10.497,1.663,2,070613,na 
SS CYG,2450702.2274,11.030,0.003,R,NO,ABS,ENSEMBLE,na,105,10.402,1.664,2,070613,na 
SS CYG,2450702.2294,10.927,0.003,I,NO,ABS,ENSEMBLE,na,105,10.292,1.667,2,070613,na 

This means your ensemble solution gave 11.235, 11.135, 11.035 and 10.935 for the B,V,Rc, and Ic (respectively) magnitudes of SS Cyg for the first group, and 11.244,11.116,11.030 and 10.927 for the second group. Your ensemble solution also gave 10.593, 10.492, 10.398, and 10.295 for the BVRcIc magnitudes of the check star for the first group.

For differential photometry, CNAME should be the name of the comparison star (chart label, GSC number, etc.): CMAG should be its instrumental magnitude. KNAME should be the name of the check star and KMAG should be the instrumental magnitude of the check star. In this manner, HQ can calculate (K-C) to determine a time-series error, and HQ can also adjust the MAG field if at some later date the true standard magnitude of the comparison star becomes known. We highly recommend that you use ABS rather than DIF format as your data will not appear on the light curve generator, nor be properly validated otherwise. The differential format is shown below:

#TYPE=EXTENDED
#OBSCODE=TST01
#SOFTWARE=GCX 2.0
#DELIM=,
#DATE=JD
#NAME,DATE,MAG,MERR,FILT,TRANS,MTYPE,CNAME,CMAG,KNAME,KMAG,AMASS,GROUP,CHART,NOTES
SS CYG,2450702.1234,1.235,0.003,B,NO,DIF,105,10.500,110,1.090,1.561,1,070613,na 
SS CYG,2450702.1254,1.135,0.003,V,NO,DIF,105,10.400,110,0.994,1.563,1,070613,na 
SS CYG,2450702.1274,1.035,0.003,R,NO,DIF,105,10.300,110,0.896,1.564,1,070613,na 
SS CYG,2450702.1294,0.935,0.003,I,NO,DIF,105,10.200,110,0.793,1.567,1,070613,na 

GROUP is a special value. It is used for grouping multiple observations together, usually an observation set that was taken through multiple filters. Then, the database software can retrieve all magnitudes from a given set and form color indices such as (B-V). If you are just doing time series, or using the same filter for multiple stars, etc., just set GROUP to "na." For cases where you want to group observations, GROUP should be an integer, identical for all observations in a group, and unique for a given observer for a given star on a given Julian Date.

Do you have a question? Try our Submitting Observations FAQ page.

To keep your observer information up-to-date in the AAVSO records, please make any necessary changes using our online Update Observer Information Form.