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solar

Sudden Ionispheric Disturbances (SIDs)

The AAVSO SID Program consists of solar observers who monitor very low frequency (VLF) radio stations for sudden enhancements of their signals. Earth's ionosphere reacts to the intense X-ray and ultraviolet radiation released during a solar flare. The ionospheric disturbance enhances VLF radio propagation. By monitoring the signal strength of a distant VLF transmitter, sudden ionospheric disturbances (SIDs) are recorded and indicate a recent solar flare event.

Solar Section

Welcome to the web pages of the AAVSO Solar Section, a world-wide group of observers dedicated to observing the closest variable star in the sky -- our own Sun!

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:

Solar Observer Celebrated in Local Paper

Solar observer Ernest Richardson was recently given the AAVSO Solar Award, which was covered in a story by the Thorne and District Gazette newspaper titled "Swinton starman receives top award ". Read the article here.

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
A-121

VLF Station List

VERY LOW FREQUENCY (VLF) RADIO STATIONS
                                     
           Station            Station     Frequency        Radiated
             Site               ID          (kHz)            Power
                                                             (kW)
  U.S. Navy                     
       Cutler, ME                NAA          24.0            1000
       Jim Creek, WA             NLK          24.8             250
       Lualualei, HI             NPM          21.4             566
       LaMoure, ND               NML          25.2             500

Solar Program, Reducing Data and Email Format

Solar Program, Reducing Data and Email Format

Reducing Data Gathered by VLF Monitoring Systems

(Extracted from SID Technical Bulletin Vol. 3, Number 4, Oct. 1992)

Pages

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