Solar Bulletin, April 2003

• Sudden Ionospheric Disturbance Report

Click image to enlarge. Fig.1. 10 cm Solar Flux and Comparison of Ri (provisional) and Ra Estimates for April 2003 (r=0.990). (Ri Source: http://sidc..oma.be/index.php3) (10cm Source: http://www.drao.nrc.ca/icarus)

Click image to enlarge. Fig.2 Maximum, Mean, and Minimum Ra Values for Each Month from January 2001 to Present.

Chair: Carl E. Feehrer

Casper Hossfield (1918-2002)
Shortly after the AAVSO's Fall meeting in Somerville, Massachusetts, I received word that Casper Hossfield, a member of the organization since the early 1960's, had passed away. Cap was chairman of the Solar Division from 1963 to 1979 and, until his death, continued to serve the Division actively in a variety of roles. During the three years that I have chaired the group, Cap was almost indefatigable in his efforts to recruit and train new solar observers and to educate people interested in building radio receivers that are capable of detecting solar flares and gamma ray bursts(GRBs). His death represents a great loss to the organization.

Reorganization of Solar Bulletin
Following Cap's death, the Supplement to the monthly Solar Bulletin that he had authored each month and that had come to contain mixed discussions of GRB detection, solar flare activity, and SID equipment was reconfigured. In the new arrangement, the coordination of discussions on design and operation of equipment and the publication of a new, bulletin focused on GRB detection and reporting has been taken over by the AAVSO's Doug Welch, while reports related to solar flare activity continue to be analyzed and published in the Solar Bulletin by Mike Hill. We feel that this arrangement more effectively maintains the focus of the original Bulletin while providing better opportunities for growth in the new area of interest to SID observers.

Participation in Sun-Earth Day at Boston Museum of Science
At the invitation of AAVSO member Larry Krozel, Mike Hill and I had the privilege of participating in the Boston Museum of Science's celebration of Sun-Earth Day on March 18. On that occasion, Mike installed in the Museum's observatory a SID receiver and antenna that he had built. This contribution enhances the Museum's ability to demonstrate solar phenomena to the public. For example, if a flare were detected with the aid of the Museum's white light and/or hydrogen-alpha telescope configurations, the receiver could be turned on and the effect of the flare on signal propagation in the ionosphere observed.

Observer/Report Statistics
Although solar activity has begun to diminish, the numbers of observers and observations remains high. There are 103 sunspot and 20 SID observers on record, with 2 new observers having been added to each group since the last period. Five thousand four hundred and fifty-six sunspot observations and 87 SID observations were submitted during the period covered by this report.

Reduction in Mailing Costs
Downloads of the web version of the Solar Bulletin have remained high since the initial publication in 2001. The response has been good enough so that it made sense to inquire how many subscribers to the publication would be willing to acquire it by downloading rather than by having it mailed to them each month. About 30% of subscribers have responded favorably to date and will now receive emailed reminders each month when the Bulletin has been posted to the website. The remainder will continue to receive the regular mailing. This should result in some reduction in the cost of Committee operations.

Acknowledgments
As in past reporting periods, the work completed in the last six months represents the outcome of a team effort. I want to extend my thanks to our loyal observers, to Mike Hill, SID Analyst and Chairperson of the Solar Flare Group, to Arthur Ritchie, who helps in the preparation of the sunspot data, and to AAVSO staff who are responsible for getting the Bulletin mailed each month and posted to the website.

Editor's Notes

Occasionally, reports generated with these programs contain user-induced errors that are not immediately obvious and that bring our processing routines to a halt. The offending report(s) and error(s) must then be identified and corrected, and the processing restarted. A list of the most common errors of this type are listed below.

A project to rewrite all of the Solar Committee's older sunspot processing software and bring it into conformity with modern standards was begun this month. I'm hopeful that error-trapping routines and other measures will be included in the new software and that the new programs will be more robust in the face of at least some of the errors on the list. In the meantime, it would be extremely helpful if observers would examine their reports before emailing them and make sure that none of these errors has been made.

Thank you.

-CEF

Common User-induced Errors in Electronic Reports

2. Missing ID in header: Be certain that your ID is contained on the "Solar data from:" line.

3. Missing name in header: Be certain that your name is included on the line following "Solar data from:" line.

4. "Homemade" report formats with incorrect column/character alignments: Some observers present their data in formats that are very similar to--but not quite identical to--the formats generated by the programs. The AAVSO processing programs are extremely sensitive to column layout and character position, and any departure from the standard produces a fatal processing error. If you have created your own approximation to the standard format, display it using a non-proportional font making sure that the column spacings and allocations are correct, and add your data using a non-proportional font (Courier is ideal).

5. Wrong reporting month/year: A substantial number of reports are received in which the "For the month of;" line contains the month that the report is mailed, not the month during which the observations were made. E.g., observations made in April but mailed in May contain the date, "May". Less frequently, the year is wrong.

6. Date not expressed in English: An unfortunate aspect of our processing routines is that they only understand English! I regret this, and I will happily "correct" the report of an observer who is unfamiliar with the English word for the month.

Michael Hill, SID Analyst 114 Prospect St Marlborough, MA 01752 USA noatak@aol.com

Observer Code Station(s) monitored A Clerkin A29 NAA J Winkler A50 NAA NPM NPR D Toldo A52 NAA NWC XXX J Ellerbe A63 ICV A Panzer A83 NAA W Moos A84 FTA M Hill A87 NAA L Anderson A91 NWC G DiFillipo A93 DHO HWU T Poulos A95 NAA R Battaiola A96 DHO J Wallace A97 NAA M King A99 HWU P Campbell A100 NLK S Bressan A101 DHO F Steyn A102 NAA NWC L Observatory A107 DHO

The events listed above meet at least one of the following criteria Event reported by two or more observers within +/- 5 minutes Event matched to GOES-8 XRA event to within +/- 15 minutes and event time < 1000 UT Reported by observer with a high quality rating > 8 (scale 1-10)

Solar Events