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observing aids

any content that aids in observing practices

Mentor Program

AAVSO mentor location - 2017

(If you are interested in becoming a volunteer mentor, please click here.)

Julian Date (JD) Calculator and Calendars

JD Calculator


What is Julian Date?
Compute the JD or UT yourself

To convert from JD to calendar date enter the Julian Date below:


WebObs is where you submit your observations to the AAVSO. You can also use this program to view, edit, and download your own observations.  To upload a file of observations, please make sure your file adheres to one of the AAVSO File Format Specifications.

V838 Mon by HST

Visual Observing Manual

The AAVSO Manual for Visual Observing of Variable Stars (ISBN 978-1-878174-00-0) is a comprehensive guide to variable star observing. Included is a lot of information and tips on how to make variable star observations and report them to the AAVSO.  The Manual is available online in .pdf format.  Translations of the Manual are available in several languages.

AAVSO Bulletin 80 for 2017

Predicted Dates of Maxima and Minima of 381 Long Period Variables for 2017

AAVSO Bulletin 79 for 2016

Predicted Dates of Maxima and Minima of 381 Long Period Variables for 2016

The AAVSO DSLR Observing Manual in Greek

A Greek translation of The AAVSO DSLR Observing Manual is now available for download.

Many thanks to Mr. Stelios Kleidis for his tremendous volunteer effort in creating this excellent translation.


AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484