From: Jin Zhu, Beijing, China Date: Fri, 17 Nov 2000 19:40:35 +0800 (CST) LEO Obs. Nov. 16/17, 2000 from China It was slightly snowing after dark, but from the weather forecast, there was good possibility that it could turn to clear after midnight. I got up at 0:20am and found that the moon was already there with several bright stars above through thin clouds. I checked the detail radiant positions as well as their average speeds for all the four showers I would like to observe, then the standard areas for limiting magnitudes. After Ju Zhao and Dan Xia came to join me at about 1:30, we discussed the observations a little and then moved sleepbags etc. to the roof of the building by the Schmidt telescope. It turned to be more and more clear after 2:00. Just at the moment of 02:28 when Dan and I went to the roof to meet Ju, a yellow -1 STA slowly appeared in front of us. I decided to look to west to eliminate the interference of the bright moon. I choosed my familar #17 AUR as my first LM area, and used a round table to block the moon behind my head when I counted the stars in this area. To avoid the possible large variation of LM introduced by the bright moon, I choosed the #2 PER near the center of my field as the second LM area. During the whole night, all of us usually could see 4 stars in #2 and 8 in #17, and I realized after observation that there are too large gaps between these areas/numbers at such a low LM (from 3.78 to 4.95 for #2 and 4.52 to 5.21 for #17) - it is obvious that the simple average of 3.78 and 4.52 will give too low value, and the real LM should be something between 4.52 to 4.95! So it should be noted that #2 is not good for such a bright moon Leonids case. However, it may also bring some problem to use areas far from the observing field. Two AMOs were seen during the night, and it seems that this shower with also very fast members should better be considered during the monitor of the Leonids. The STA and NTA could be easily distinguished from their slowly moving and short arcs near their radiants. It seems that there were some very fast meteors came from somewhere further eastwards to Leo. At 4:27, Ju saw a very fast +2 meteor at somewhere out of my field and shouted, Dan and I turned our heads to him immediately and we saw a very fast +0 SPO just there - this was obviously not the same one Ju referred to, but it seemed that the two may probably came parallelly from somewhere in the east. After 4:30, feeling that the moon was too high and blocking it gave me a little narrow clear field, I removed the table and change my field center rightward to zeta Perseus, having the moon inside my field at the far left side. The LM seems not change but from that time, I almost saw no meteors again for the following 30 minutes except two satellites (the only ones I saw that night). It seems that blocking the moon from your field is very important if you have to observe in such situation - this was my first time to observe meteors during moonlight and it had quite different feeling. This was also my first time to use a digital voice recorder and which worked well. So the voices could be easily recorded as computer files. The complete report is as followes: *************************** NAMN VISUAL SUMMARY REPORT *************************** DATE: Nov. 16/17, 2000 BEGIN: 18:43 UT END: 21:03 UT OBSERVER: Jin Zhu (ZHUJI) LOCATION: Long: 117 d 34' 42" East; Lat: 40 d 23' 47" North Place: Xinglong, Hebei, CHINA Elevation: 860 m. RECORDING METHOD: Voice Recorder --------------------------------------------------------------------- OBSERVED SHOWERS: 3-letter code; radiant position; radiant diameter LEO ; RA 10h 02m DEC +23 deg.; STA ; RA 04h 03m DEC +16 deg.; NTA ; RA 04h 12m DEC +23 deg.; AMO ; RA 07h 31m DEC +02 deg.; --------------------------------------------------------------------- OBSERVING PERIODS: 0 = none seen; / = shower not watched. PERIOD(UT) FIELD Teff F LM LEO STA NTA AMO SPO 18:43-20:00 RA 4h 30m DEC +30 deg 1.30 1.05 4.8 3 2 1 2 1 20:01-21:03 RA 4h 00m DEC +30 deg 1.05 1.05 4.9 5 0 0 0 2 --------------------------------------------------------------------- TOTALS 2.35 8 2 1 2 3 --------------------------------------------------------------------- MAGNITUDE DISTRIBUTIONS: SHOWER -7 -6 -5 -4 -3 -2 -1 0 +1 +2 +3 +4 +5 +6 TOTAL LEO 0 0 0 0 1 1 0 1 1 0 3 1 0 0 8 STA 0 0 0 0 0 0 0 1 1 0 0 0 0 0 2 NTA 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 AMO 0 0 0 0 0 0 0 0 1 0 1 0 0 0 2 SPO 0 0 0 0 0 0 0 1 1 0 1 0 0 0 3 --------------------------------------------------------------------- Total 0 0 0 0 1 1 0 3 4 0 6 1 0 0 16 --------------------------------------------------------------------- SKY OBSCURED: Percentage(%) Duration (UT) 5 18:43-20:00 10 20:26-20:30 5 20:31-21:03 --------------------------------------------------------------------- DEAD TIME: None BREAKS: None --------------------------------------------------------------------- LIMITING MAGNITUDE: STAR STAR TIME AREA COUNT LM 18:43 17 8 4.52 18:50 2 5 4.95 19:18 2 5 4.95 19:23 17 8 4.52 19:34 2 4 3.78 19:48 2 5 4.95 19:56 2 5 4.95 19:56 17 8 4.52 20:04 17 8 4.52 20:05 2 5 4.95 20:14 17 8 4.52 20:26 17 8 4.52 20:36 17 8 4.52 20:36 2 5 4.95 20:54 17 8 4.52 21:03 17 8 4.52 MEAN LIMITING MAGNITUDE: 4.8 --------------------------------------------------------------------- METEOR DATA: # TIME(UT) MAG VEL. COLOR SHOWER TRAIN MAP ACCURACY --------------------------------------------------------------------- 1 18:53 +0 2 y STA 2 18:56 +3 5 w SPO 3 19:00 +3 5 w LEO 4 19:00 +1 2 w STA 5 19:02 +1 5 w AMO 6 19:29 +0 5 w LEO 7 19:29 +3 5 w AMO 8 19:45 -2 5 w LEO 1s 9 19:57 +3 1 w NTA 10 20:08 +1 5 w LEO 0.2s 11 20:15 +4 5 w LEO 12 20:22 +3 3 w LEO 13 20:23 +1 5 w SPO 14 20:27 +0 5 w SPO 15 20:28 -3 4 w LEO 1s 16 20:31 +3 5 w LEO VELOCITY (VEL.) SCALE: 0 = Stationary 1 = Very Slow 2 = Slow 3 = Medium 4 = Fast 5 = Very Fast --------------------------------------------------------------------- REMARKS: The data was extracted from voice recorder by Dan Xia. --------------------------------------------------------------------- Original records: # TIME(UT) SHOWER MAG SPEED TRAIN(SEC) MEM 18:43 start FOV: RA 4h 30m DEC +30 deg showers: LEO,STA,NTA,AMO LM: 17/8, 2/5 18:43 LM: 17/8 18:50 LM: 2/5 01 18:53 STA +0 2 yellow 02 18:56 SPO +3 5 03 19:00 LEO +3 5 04 19:00 STA +1 2 05 19:02 AMO +1 5 19:18 LM: 2/5 19:23 LM: 17/8 06 19:29 LEO +0 5 07 19:29 AMO +3 5 19:34 LM: 2/4 08 19:45 LEO -2 5 1s 19:48 LM: 2/5 19:56 LM: 2/5 19:56 LM: 17/8 09 19:57 NTA +3 1 20:04 LM: 17/8 20:05 LM: 2/5 10 20:08 LEO +1 5 0.2s 20:14 LM: 17/8 11 20:15 LEO +4 5 12 20:22 LEO +3 3 13 20:23 SPO +1 5 20:26 LM: 17/8 14 20:27 SPO +0 5 15 20:28 LEO -3 4 1s 20:30 FOV: RA 4h 00m DEC +30 deg table 16 20:31 LEO +3 5 20:36 LM: 17/8 20:36 LM: 2/5 20:52 bright satellite +3 WNW->ESE flash 20:54 LM: 17/8 20:57 another bright satellite +3 S->N across the #17 LM area 21:00 LM: 17/8 21:03 end