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Solar Bulletin, April 2004

Solar Bulletin

THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS - SOLAR COMMITTEE
Carl E. Feehrer, Editor
9 Gleason Rd.
Bedford, MA 01730		Email: cfeehrer@hotmail.com

ISSN 0271-8480
Volume 60 Number 4April 2004
Table I. Mean Sunspot Numbers for April 2004
[boldface = maximum, minimum]		Table II. April Observers
Day N Raw Mean Ra
1 36 73 53
2 36 68 49
3 33 60 46
4 33 73 55
5 44 74 53
6 41 55 39
7 37 48 34
8 35 32 23
9 44 23 17
10 41 18 14
11 34 18 15
12 34 32 25
13 33 45 32
14 39 52 39
15 42 45 33
16 38 45 33
17 31 66 48
18 35 81 56
19 32 81 59
20 41 81 59
21 41 79 58
22 41 71 53
23 37 49 36
24 40 48 36
25 40 45 33
26 42 43 32
27 38 38 28
28 36 32 23
29 38 31 22
30 36 47 33
31 --- --- ---
Means:37.651.837.9
No. of Observers: 72
No. of Observations: 1128

Reporting Addresses

Sunspot Reports -- email: solar@aavso.org

postal mail: AAVSO, 25 Birch St. Cambridge, MA 02138
FAX (AAVSO): (617) 354-0665

SID Solar Flare Reports -- email: noatak@aol.com

postal mail: Mike Hill 114 Prospect St. Marlboro, MA 01752
12 AAP P.Abbott
28 ARAG G.Araujo
11 ATON A.Attanasio
11 BARH H.Barnes
10 BATR R.Battaiola
12 BEB R.Berg
13 BERJ J.Berdejo
2 BLAJ J.Blackwell
10 BMF M.Boschat
24 BOSB B.Bose
25 BRAR R.Branch
27 BROB R.Brown
6 BXA A.Baransky
9 CAMP P.Campbell
13 CARJ J.Carlson
26 CHAG G.Morales
23 CKB B.Cudnik
7 CLZ C.Laurent
19 COMT T.Compton
27 CR T.Cragg
24 DEJV J.van Delft
2 DEMF F.Dempsey
11 DGP G.Dyck
11 DPP P.dePonthiere
22 DRAJ J.Dragesco
25 DUBF F.Dubois
15 FEEC C.Feehrer
14 FERJ J.Fernandes
20 FLET T.Fleming
24 FUJK K.Fujimori
23 GOEM M.Goetz
2 GOLA A.Golovin
26 GUNM M.Gundlach
10 HALB B.Halls
10 HAYK K.Hay
13 HRUT T.Hrutkay
17 JAMD D.James
14 JEFT T.Jeffrey
11 JENJ J.Jenkins
25 KAPJ J.Kaplan
4 KHAR R.Khan
20 KNJS J&S Knight
8 KQR R.Kinne
1 KROL L.Krozel
6 LARJ J.Larriba
11 LERM M.Lerman
5 LEVM M.Leventhal
10 MARE E.Mariani
30 MARJ J.Maranon
14 MAV D.Matsnev
22 MCE E.Mochizuki
23 MMI M.Moeller
16 OBSO IPS Observatory
15 RICE E.Richardson
17 RITA A.Ritchie
27 SCGL G.Schott
6 SCHG G.Scholl
1 SDP S.Sharples
10 SIMC C.Simpson
3 STEF G.Stefanopoulis
24 STEM G.Stemmler
18 STQ N.Stoikidis
25 SUZM M.Suzuki
24 SZUM M.Szulc
27 TESD D.Teske
13 THR R.Thompson
19 TJV J.Temprano
25 URBP P.Urbanski
16 VARG A.Vargas
12 VELM M.Velea
21 WILW W.Wilson
21 YESH H.Yesilyaprak

Table III. Means of Raw Group Counts (RG) and Ratios of Spots to Groups (S:G) in April   2004
Day RG S:G Day RG S:G Day RG S:G Day RG S:G
1 3.9 8.8 9 1.4 6.1 17 4.9 3.3 25 2.5 8.2
2 4.2 6.1 10 1.2 4.5 18 5.1 5.9 26 2.6 6.3
3 4.1 4.6 11 1.3 4.2 19 4.3 8.9 27 2.5 5.4
4 4.7 5.6 12 2.3 3.9 20 4.5 8.2 28 2.2 4.3
5 4.7 5.9 13 3.0 4.8 21 4.6 7.0 29 2.3 3.3
6 3.3 6.9 14 3.5 4.8 22 3.9 8.4 30 2.9 6.3
7 3.0 6.1 15 3.2 4.1 23 2.6 8.6 31 --- ---
8 1.9 6.8 16 3.5 2.8 24 2.9 6.6 Mn. 3.2 5.9

Figure 1
Click image to enlarge.
Fig. 1. 10 cm Solar Flux and American Relative Sunspot Numbers (Ra) for April 2004
(10cm Source: http://www.drao.nrc.ca/icarus)

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

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

Sudden Ionospheric Disturbances (SID) Recorded During April 2004

(Analysis performed by Michael Hill, SID Analyst)
Date Max Imp Date Max Imp Date Max Imp
040401 1713 2 040423 0931 1-      
040404 1624 2 040423 0950 1      
040405 0554 1+ 040423 1045 1-      
040406 0536 1+ 040423 1149 1+      
040406 1324 2+ 040423 1204 1      
040406 1331 2+ 040423 1605 2+      
040408 0149 1 040423 1608 1+      
040408 1018 2+ 040423 1724 2      
040408 1320 2+ 040423 1733 2      
040411 0419 1- 040423 1906 1      
040412 0750 1+ 040423 2110 2      
040415 1644 2 040423 2256 1+      
040416 1442 1 040424 0209 1      
040419 0034 1- 040424 0551 1      
040419 1834 2+ 040424 0904 2      
040421 0304 2+ 040424 1302 1+      
040421 1454 1+ 040424 1404 1+      
040421 1500 1+ 040424 1528 1+      
040421 1617 2 040425 0146 1+      
040422 0221 1+ 040425 0537 2      
040422 1415 2 040425 1016 1      
040422 1451 1- 040425 1614 2      
040423 0456 1 040426 0251 2      
040423 0655 2+ 040427 0722 2+      
040423 0757 2+ 040430 0547 1      


Importance rating: Duration -1: <191: 19-251+: 26-322: 33-452+: 46-853: 86-1253+: >125

Observer Code Station(s) monitored
A Clerkin A29 NAA
J Winkler A50 NAA NML
D Toldo A52 NAA NSS NWC
J Ellerbe A63 ICV
P King A80 FTA
W Moos A84 FTA
M Hill A87 NAA
L Anderson A91 NWC
G DiFillipo A93 DHO HWU
T Poulos A95 NAA
J Wallace A97 NAA
M King A99 HWU
P Campbell A100 NLK
F Steyn A102 NWC
B Bose A103 VTX
P Mortfield A108 NLK
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)

SID ratings

Solar Events

April was an interesting month. Overall there was not a lot of activity but there was a surge of it on and around the 23rd which resulted in a fairly high count for SID events. In all there were 50 correlated SID events this month. All had an importance rating of 2+ or less. They were pretty evently spread across the month but note the sudden peak on the 23rd followed by 3 fairly active days afterwards. These were all attributed to active region 597 which I'm sure some of you followed visually as well. The increase in activity mirrored quite closely the activity level seen by the GOES-12 satellite. It detected a total of 291 X-Ray flares this month, quite an increase from last month where there were only 206. Interestingly last month there were more SIDs detected so the flares, on average must have been more powerfull last month. Of the 291 flares, only 5 were M-Class and there were no X-Class events. On the 23rd there were 21 flares, 2 of them M-Class.

Just a friendly reminder about data formats. The data you send me should be in an attached file that has the proper format as discussed on the AAVSO SID web site. The file must be a non-formatted text file and it should be named according to your observer ID and the Station monitored. For example A87NAA.DAT. Please make sure your data is in this format. Otherwise it will not be processed unless you can resubmit it after reformatting.

Solar Flare Summary
 
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