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Observing Variable Stars

Multiwavelength observations of SS Cygni

Update: 2010 May 10

AAVSO Veterans, Peace Corps, VISTA, and more

Watch this page as we add information from you and from our archives!

Are you a veteran? Are you currently serving or have you served in the Armed Forces of the United States, your own country, or another country? The Red Cross or Red Crescent?  The Peace Corps? VISTA? Other similar organizations?

If yes, have you had interesting experiences related to your service and variable star observing or astronomy in general? Would you be willing to share them with us?

Observer Awards

Without the nightly observations of amateur astronomers, the professional astronomer would find it difficult, if not impossible, to collect the quantity of data that is needed to further the study of stars, the Sun, novae and supernovae, comets, and meteors.

Standardized Magnitude

The standardized magnitude for the variable is given by

Vstd = (Vins - Cins) + Cstd

where Vins is the instrumental magnitude of the variable, Cins is the instrumental value of the comparison, and Cstd is the chart magnitude for the comparison (or the equivalent for ensemble photometry).

Note that 'standardized' does NOT mean that Landolt Standards were used as comparison stars.


AAVSO Unique Identifier

What Is The Name of That Star?

"What is the name of that star?" This is a question that many a young observer has asked their mentors. As astronomers we know that stars have many names - proper names, Bayer and Flamsteed Designations, and the Henry Draper Catalogue, for example.

AAVSO Extended File Format

Version: 1.2
Release Date: July 27, 2011 (latest update: June 13, 2017)

This is one of two ASCII formats that the AAVSO accepts for uploading a file of variable star observations. Please use the WebObs File Upload page to upload your file in the AAVSO Extended Format. The other format , which is intended for visual observers, is called the AAVSO Visual File Format.

AAVSO Visual File Format

Version: 1.0
Release Date: January 15, 2008

This is one of two ASCII formats that the AAVSO accepts for variable star observations. Observations in this format may be submitted using the WebObs File Upload Tool. The other format is intended for CCD, DSLR, PEP, and VISDIG (visual observations made from digital images) observers and is called the AAVSO Extended File Format.

Obtaining your PEP epsilon(V) coefficient

Making Observations for Obtaining Epsilon-V Coefficient Using the Two-Star Method


Assuming you have a suitable photoelectric photometry system (telescope and photometer), you will also need the following:


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