SSOC Tohban Report for Week 51 (20 DEC - 26 DEC 1993) A. Takeda, Y.Nishino (SSOC) K. Yaji , H.Watanabe (KSC) 0. General The plan to take the SXT 'terminator images' with spacecraft offset was successfully carried out last week. The aim of S/C offset was to use the terminators to calibrate the deep coronal images. 1. Solar Activity A total of 4 M-class flares occurred during our toban week, thanks to a energetic AR of NOAA 7640 which came up from the east limb early in the week and is approaching central meridian now. The X-ray background level(GOES 1-8A) reached the c-level. Thus, 85 flares above class B2 occurred in this period (according to GOES_summary). This might have been a Christmas present for Yohkoh team, but our satellite unfortunately failed to catch the all phases of any of the M-class flares because of night intervals. But, a few flares of C6 class seems to have been detected. 2. Standard Operations 2.1 SXT Table Uploads: pass (UT) (Tue) 21-Dec #2 "931221 T1 P2 DEEP CORONA" (Tue) 21-Dec #4 "931221 T1 P4 ARS1 DKCAL" (WED) 22-Dec #1 "931222 T1 P1 ARS1 STD Q" (Thu) 23-Dec #1 "931223 T1 P1 ARS1 STD Q" (Fri) 24-Dec #2 "931224 T1 P1 ARS1 STD Q" Most of these tables were uploaded in order to take terminator images through all available filters (see section 3.1). 2.2 STT Timer Set The STT timer was set on Monday, 20 December at pass#1, and the next timer set is scheduled on 27 December at pass#5. We decided to choose this pass because the earlier passes are day time ones from which we can get more real time images of the 'active' sun of these days. We planned this timer set to keep available until the end of the new year holiday. 2.3 Weekly Offset Pointing The deep corona observations with 8'offpointing were performed on 21-Dec, one day earlier than scheduled before. This is because there was the NOAA7640 just on the east limb. 3. Special Operation 3.1 Terminator images with S/C offset We manually added the OGs to the OP created by the op_first_ guess program, OGs which correspond to offset and normal pointing. 921222-0514OP --- east 8' offset 921223-0412OP --- west 8' offset 921224-0516OP --- west 8' offset 921225-0310OP --- east 8' offset Combination of filters has been changed by uploading the new SXT table. This project will go on for the following weeks. 3.2 BCS calibration A BCS calibration was scheduled at pass 2 on 23 Dec. It was performed safely. 4. DSN communications 4.1 Strawman Non-Arrival The strawman schedule for week 02 has not yet arrived, probably due to the Christmas holiday in the USA. We therefore could not arrange the DSN schedule from 10 to 16 Jan. Though we already asked JPL to make it available on RASM, the task of checking and cancelling the DSN passes is left for a toban of this week. 4.2 Unexpected Cancellation of Preliminary Schedule We found the following 4 DSN passes in week01 which were listed on the Strawman but are not included in the preliminary schedule. There were not any traces of can- cellation. Now we are waiting for the reply to our inquiry about the reason. DOY 4 BOT 1505 EOT 1514 DSS 46 PASS 3298 DOY 6 BOT 1403 EOT 1412 DSS 46 PASS 3327 DOY 6 BOT 1547 EOT 1555 DSS 46 PASS 3328 DOY 6 BOT 1618 EOT 1627 DSS 16 PASS 3328 4.3 DSN Data Delay DOY 351 BOT 0330 EOT 0339 DSS 46 PASS ???? The above data have not arrived because of some tape trouble. They are to be sent as soon as possible. The request was made though telephone directly by Nitta san. 5. Problems, Errors, etc 5.1 Yohkoh Errors Yohkoh was calm and quiet last week, against the high activity of the sun. Only one error occurred last week. SXT BITMAP ERROR at pass1 on 21 Dec. 5.2 Toban Errors Since both SSOC tobans were `green', there were many mistakes on OPs and command sheets. They were all corrected by reliable KSC tobans. The largest error on the part of the SSOC tobans was that they forgot to transfer OP to KSC on 24 Dec. The scheduled OP write and SXT table write were postponed to the second pass. 5.3 Other Problems - SSOC#2 mainframe was usually shut down on National holidays and 2 weekend days. We, hence, had to keep in mind the mainframe condition every holiday operations, which should be put on the TOBAN DUTIES MANUAL. In addition, there isn't detail description of the DSN communication log book in the manual. It must be stressed more. - There are many returned messages in mail spool and in mbox file. Some address needs to be deleted or updated. 6. Hikitugi 6.1 Week 52 ohbans: SSOC: T. Watanabe KSC : K. Yaji 6.2 The STT timer set Next timer set was scheduled at 4th January. 6.3 Duties left Check of the preliminary schedule for week 02(see section 4.1). 6.4 Year End/Start Schedule We will finish this year's last Yohkoh operation at pass#5 on Dec.28(11:00UT). The first Yhokoh operation next year starts at pass#1 on Jan.4(10:00UT).