Reporting Variable-Star Observations

Why Record Your Observations?

For over 100 years amateur astronomers have been making an important contribution to astronomical research through their long-term observation of variable stars. The RASC supports this research through our involvement with the American Association of Variable Star Observers.

What Needs to be Reported

Regadless of what method you use for submitting your observations you will need to record your data in the field as you make each variable star estimatation. The AAVSO provides forms that can be used in the field to gather data:

Reporting via WebObs

With WebObs you can send your observations through the internet to the AAVSO where they will be automatically checked for errors and added to the AAVSO database. This method allows for nearly instant feedback as you can then use the AAVSO's Light Curve Generator to see how your observations compare with recent observations from other observers. This program is free and can be used by both members and non-members of the AAVSO (although you do have to register to receive your Observer's Code Initials).

Regardless of what format you choose you will need to record the following information in the field as you make your variable star observations. More information on the reporting standards used by the AAVSO is available from their free publication Manual for Visual Observing of Variable Stars.

  • Designation in the form of the stars Right Ascension and Declination. (e.g. R Andromedae is 0018+38)
  • Variable Name in short form. (e.g. R Andromedae is R And)
  • Julian Date and decimal fraction of the time of day in GMAT format. (e.g. 2451845.7) See the Computing Julian Day and Time page at the AAVSO for more information about this important topic.
  • Magnitude Estimate that you determined to one decimal place. (e.g. 8.5)
  • Key Comment Codes using one letter AAVSO abbreviations(e.g. "H" means equals haze, mist, or fog present)
  • Remarks for any additional remarks you may have. (e.g. Cold night)
  • Comparison Stars that you used for the estimate. (e.g. 8.0, 8.3, 8.7, 8.9)
  • Chart Scale (letter from a-f) and Date taken from the chart used for the observation (e.g. S/D 1949 where S is standard chart and D is the chart scale)
  • Observer's Initials in the form of letters designated to you by the AAVSO. (e.g. DJQ)

Other Reporting Methods

Sending by Mail or Fax

The AAVSO will accept observations sent by mail or fax using the appropriate reporting forms. Find out more from the AAVSO website:

  • Submitting observations by fax
  • Submitting observations by mail

Bear in mind that both of these methods will delay your observations being entered into the AAVSO database.

AAVSO Manual

AAVSO Observing Manual

Last modified: 
Saturday, January 17, 2015 - 12:27pm