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solar observing

SunEntry - A sunspot data entry program

SunEntry is a data entry program for solar observers. It will help you to create reports and send them to our database where they will be used in the AAVSO American Relative Sunspot Program. The information you submit will also be used in the monthly Solar Bulletin.

Getting Started

Before you can use SunEntry, you must have an AAVSO website account and an AAVSO Observer code if you don't already have both. Here are instructions on how to get them:

What are sunspots?

The term "sunspot" appears in the news, often in connection with stories on aurorae, electrical outages, and problems with orbiting satellites.  But often these stories don't really explain what sunspots are and why they're of interest to us on Earth.  So what are sunspots?

The Gyrator III VLF Receiver

The latest version of the Gyrator series of VLF receivers (first developed in the 1990s) is the Gyrator III, a revision of Arthur Stokes' Gyrator II by Guglielmo Di Filippo (observer A-93).

Circuit diagrams and wiring for the Gyrator III are available here in Microsoft Word and PDF formats: .doc, .pdf

AAVSO Sudden Ionospheric Disturbance Program Observers

Active Observers (Data submitted within the last year)

OBS ID Observer Name Station Location
A-94 Al McWilliams St Cloud, MN
A-96 Roberto Battaiola Milan, Italy
A-97 Jon Wallace Torrington, CT
A-118 Lionel Loudet Muret, France
A-120 Bob Terrill Ballarat, Victoria, Australia

SID Database

About the SID database

The Sudden Ionospheric Disturbance (SID) Database lists all events identified in the AAVSO Solar Bulletin. These results are provided monthly by the worldwide network of SID observers in the AAVSO Solar Division. Individual results are correlated with other observers' reports and reduced to a list of events with high definiteness ratings.

The Zurich Classification System of Sunspot Groups

The Zurich Classification System of Sunspot Groups

Contributed by Tom Fleming (FLET)


"A" Type: One or more tiny spots that do not demonstrate bi-polarity or exhibit penumbra.


"B" Type: Two or more tiny spots that demonstrate bi-polarity but do not exhibit penumbra.






Dances with Wolfs: A Short History of Sunspot Indices

Contributed by Carl E. Feehrer (FEEC)

Revised August 2000

Accuracy and Consistency in the Production of the American Sunspot Number (Ra)



Contributed by Carl E. Feehrer (FEEC)

Solar News

February 20, 2013

  • The NASA SDO mission released a fascinating video showing "rain" from a magnetic loop falling back onto the surface of the Sun.  It's not rain, but hot plasma magnetically levitated off the Sun!

February 15, 2013


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