NRO Heliograph Tohban's Report for Week 19 (4 May 1998 - 11 May 1998)

                                    Tohbans : T. Yokoyama and Y. Hanaoka

1. Solar Activity

   We had a very 'active' AR 8210 this week.
   There were one X-class flare and 5 more-than-M2 class flares.
   The NRH missed the X-class one. But two of the
   more-than-M2 class flares were detected. The event
   #19980509_0344 occurs on the west limb.

2.  Remarkable Events found by NRH

 2.1  M7.7 limb flare on 1998-05-09

   A upper-middle class flare occured on the west limb
   just before the very 'active' active region 8210 went 
   beyond the limb. The event duration in soft X-ray was 
   nearly 3 hours.  Plasma eruptions were associated with this event.

 2.2 other activities in AR 8210

   We had another 5 events, whose peak value in the correlation plots were 
   above 500 counts. 4 of them were C class flares, and the other one was
   the M3 disk-flare. All events occured in AR 8210.