Gema Araujo took these images on April 30, 2007 at 09:48 and 10:04 UT of active region 10953.

I would have liked to spring an April Fools joke on everyone and show a chart of solar max, but instead we saw the sunspot count dip a fraction lower than last month. On the good side we had more sunspot observations for the month and even a report of a SID.

I came across a binder with some of my old solar observations during 1975-1976 and noticed long stretches of observations with minimal and many zero counts from that cycle. It sure made for quick observations especially between university classes with the campus telescope. At some point I will follow GemaÕs lead and scan all these observation pages to store them online. ItÕs probably a better way of preserving them for the future.

While activity in this part of the cycle may be low, the group leaders Dan Williams (sunspot observations), and Mike Hill (SID observations) are busy compiling your monthly observations for the bulletin and deserve a vote of thanks from all of us for their ongoing efforts.

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

The events listed above meet at least one of the following criteria

1. Event reported by two or more observers within +/- 5 minutes
2. Event matched to GOES-8 XRA event to within +/- 15 minutes and event time < 1000 UT
3. Reported by observer with a high quality rating > 8 (scale 1-10)

April was another slow month for SID activity. I say slow instead of non-existent since we did have one observer with a correlated event. That was one more than last monthÕs zero count however so quite an increase in activity by comparison. The GOES-12 satellite recorded only 39 X-Ray flares and of these only two were significant. One on the 24th which was a C2.8 event and the other on the 27th which was a B6.3 event. This is the one correlated event. As you can see from the graph below, activity was non-existent until the 24th when it did suddenly pick up quite a bit for the rest of the month. Thanks to all of you for submitting reports. You will all be noted in the SID Database report that appears in the AAVSO web site.

Solar Flare Summary Based on GOES-12 Data

Sunspot Data

American Relative Sunspot Numbers(Ra) for April 2007 [boldface = maximum, minimum] Day N Raw Mean Ra 1 34 7 4 2 32 2 1 3 28 2 1 4 24 0 0 5 30 0 0 6 36 0 0 7 34 1 0 8 30 0 0 9 29 0 0 10 29 0 0 11 36 0 0 12 31 0 0 13 29 1 1 14 28 1 0 15 40 0 0 16 30 0 0 17 31 3 2 18 27 0 0 19 37 0 0 20 36 0 0 21 41 0 0 22 37 1 0 23 32 0 0 24 28 0 0 25 30 13 9 26 32 17 12 27 29 17 13 28 37 23 18 29 38 32 23 30 34 32 23 Means 32.3 5.1 3.6 Total No. of Observers: 58 Total No. of Observations: 969

April 2007 Sunspot Observers AAP A. Abbott 14 AJV J. Alonso 15 ARAG G. Araujo 30 BARH H. Barnes 13 BATR R. Battaiola 14 BEB R. Berg 8 BERJ J. Berdejo 11 BMF M. Boschat 16 BRAB B. Branchett 27 BRAD D. Branchett 20 BRAM M. Bradbury 1 BRAR R. Branch 16 BROB R. Brown 18 BVC A. Buck 30 BYG Y. Brovarets 34 CHAG G. Morales 26 CKB B. Cudnik 22 CLZ L. Corp 12 COMT T. Compton 11 DEJV J. van Delft 15 DGP G. Dyck 15 DUBF F. Dubois 30 FLET T. Fleming 22 GFT F. Gobet 17 GOEM M. Goetz 13 HALB B. Halls 14 HAYK K. Hay 10 JENS S. Jenner 8 KAPJ J. Kaplan 25 KNJS J. & S. Knight 13 KQR R. Kinne 2 KROL L. Krozel 1 KUZM M. Kuzmin 5 LARJ J. Larriba 13 MARE E. Mariani 17 MCE E. Mochizuki 24 MCHL L. McHenry 1 MEU E. Mason 4 MMI M. Moeller 25 OATS S. Oatney 22 OBSO IPS Observatory 12 PEKT R. Pektas 28 RICE E. C. Richardson 17 RITA A. Ritchie 18 SCGL G. Schott 30 SCHG G. Scholl 5 SIMC C. Simpson 12 STEF G. Stefanopoulis 19 STEM G. Stemmler 25 SUZM M. Suzuki 22 SZUM M. Szulc 21 TESD D. Teske 28 TJV J. Temprano 9 URBP P. Urbanski 27 VARG A. Vargas 23 VIDD D. Vidican 7 WILW W. Wilson 26 WRP R. Wheeler 6

Reporting addresses: Sunspot Reports Email: solar@aavso.org Postal Mail: AAVSO, 49 Bay State Rd. Cambridge, MA, 02138 Fax: 617-354-0665 SID Flare Reports Email: noatak@aol.com Postal Mail: Mike Hill, 114 Prospect St., Marlboro, MA, 01752

10 cm Solar Flux and American Relative Sunspot Numbers (Ra) for April 2007 (10cm Source: http://www.drao.nrc.ca/icarus)

Smoothed Mean Sunspot Numbers (Rsm) from January 2000 to October 2006 (Waldmeier method).