NRO Heliograph Tohban's Report for Week 33 (9 August 1999 - 15 August 1999)

                                                    Tohban : Y. Hanaoka

1. Solar Activity

Solar activity was not high through this week.  There were many
B-class and low C-class flares, but there was no M/X-class flare.  The
sun at 17 GHz was also inactive, and all the flares observed were not
so remarkable.

  NoRH event list of week 33
----------------------------------------------------------------
   DAY       START        END     MAX.TIME   DUR.  MaxCor | GOES  
              (UT)        (UT)      (UT)    (sec)  (10^-4)| class  
1999-08-08  22:30:22#   22:41:56  22:30:23    694      7    
1999-08-09  06:01:01    06:01:27  06:01:03     26      7    
1999-08-09  22:30:24#   23:13:59  22:33:29   2615      9    
1999-08-09  23:32:45    00:01:58  23:37:49   1753      9    
1999-08-10  06:04:22    06:30:24# 06:09:54   1562     17    
1999-08-10  22:30:25#   22:56:28  22:31:09   1563      7    
1999-08-11  03:12:47    03:15:53  03:13:24    186      7    B8.2
1999-08-11  22:33:27    22:46:29  22:33:30    782      7    
1999-08-12  02:57:40    03:06:50  02:58:18    550      9    C2.4
1999-08-13  06:08:58    06:17:45  06:11:17    527      7    
1999-08-14  04:23:59    04:24:57  04:24:08     58      9    B9.0
1999-08-14  05:50:37    06:16:19  06:06:54   1542      8    
1999-08-14  06:17:25    06:30:22# 06:28:10    777      8    
1999-08-15  01:20:56    01:21:45  01:21:15     49     17    C4.6

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2. Remarkable Events found by NRH

Although there was no remarkable flare, we observed some interesting
events.

(1) A series of prominence eruption was observed on August 12.  The
first prominence eruption at the NW limb has started before the
beginning of our observation.  The second one was a surge-like
activation at the NE limb..  The third one was another prominence
eruption at the NW limb.  A gradual brightening just on the NW limb
was going on through the two eruptions at the NW limb.  A splendid CME
was observed by LASCO of SOHO, and this is probably associated with the
first prominence eruption.  A geomagnetic disturbance on August 15,
which is presumed to be caused by this CME, was reported.

(2) A compact flare in NOAA 8662 was accompanied by a mass ejection.
Bright ejecta was observed at 17 GHz.  This mass ejection is also seen
in SOHO EIT 195 A images.

(3) A disappearing prominence was observed on August 14 at the NE
limb.

The details of these events are reported in the NoRH tohban's web page, 
http://solar.nro.nao.ac.jp/~tohban/event/events.html.

3. Observing log

An instrumental test was carried out on August 9.  Due to this test,
the E28 antenna was not used for the observation during 00:00-03:00 UT,
and the E27 antenna was not used during 04:40-07:00 UT.

A failure of the electric power supply took place on August 12 at
night.  We could not start the observation on August 13 until 05:05 UT
after the recovery of the computers.

4. Next tohban (week 34)

  H. Nakajima

+--End of Report--