Report of The Leonids Shower 2001

We tried to observe the meteor shower of Leonids at Nov.18/19.
We observed the meteor shower peak around 18h00m-18h30m(UT).
This hourly rate(HR) was over 2000!
After this peak, the number of meteors decreased slowly. But we could watch a lot of meteors in blue sky of twilight.

Report of visual observations

Nov.18-19/2001
Date  Time(UT)      min   Ls      h    Lm  Cl All Leo   HR  CHR  ZHR   Obs.        
-----+--------------+--+-------+-----+----+--+---+---+----+----+-----+------------------
Count with a counter
18.64 15h00m-15h30m  30  236.33  14.5  5.9  0 *1   45   90  119  956  Nakamura Kiyohide
18.66 15h30m-16h00m  30  236.35  20.3  5.6  0 *1   87  174  266 1296  Sato Tomoko
18.68 16h00m-16h30m  30  236.37  26.3  6.1  0 *1  131  262  316 1072  Sato Mikiya
18.70 16h30m-17h00m  30  236.40  32.3  6.1  0 *1  243  486  587 1499  Terakubo Kazumi
18.72 17h00m-17h30m  30  236.42  38.4  5.7  0 *1  361  722 1052 2146  Nakamura Kiyohide
18.74 17h30m-18h00m  30  236.44  44.5  5.7  0 *1 1035 2070 3015 5137  Sato Tomoko
18.76 18h00m-18h30m  30  236.46  50.6  5.9  0 *1 1198 2396 3177 4681  Sato Mikiya
18.78 18h30m-19h00m  30  236.48  56.5  6.1  0 *1  797 1594 1924 2526  Terakubo Kazumi
18.80 19h00m-19h30m  30  236.50  62.3  5.9  0 *1  493  986 1307 1570  Nakamura Kiyohide
18.82 19h30m-20h00m  30  236.52  67.7  5.3  0 *1  441  882 1550 1743  Sato Tomoko
18.84 20h00m-20h30m  30  236.54  72.3  5.1  0 *1  225  450  869  935  Sato Mikiya
18.86 20h30m-21h00m  30  236.56  75.4  *2   0 *1   54  108   *2   *2  Terakubo Kazumi

Count with a tape recorder
18.68 16h05m-16h35m  30  236.38  27.3  5.7  0 *1  120  240  350 1125  Nakamura Kiyohide
18.70 16h35m-17h05m  30  236.40  33.4  5.7  0 *1  210  420  612 1500  Sato Tomoko
18.72 17h05m-17h35m  30  236.42  39.4  5.7  0 *1  364  728 1060 2094  Sato Mikiya
18.74 17h35m-18h05m  30  236.44  45.5  5.9  0 *1  957 1914 2538 4211  Terakubo Kazumi
18.76 18h05m-18h35m  30  236.46  51.6  5.9  0 *1  997 1994 2644 3814  Nakamura Kiyohide
18.78 18h35m-19h00m  25  236.48  57.0  5.7  0 *1  619 1486 2164 2817  Sato Tomoko
18.81 19h05m-19h35m  30  236.50  63.2  5.9  0 *1  434  868 1151 1365  Sato Mikiya
18.83 19h35m-20h05m  30  236.52  68.5  5.4  0 *1  290  580  973 1084  Terakubo Kazumi

*1:Count only Leonids
*2:Limited magnitude was no-good because of twilight.

Place:Hara village (Nagano pref. Japan)
      138d 17.1'E, 35d 58.9'N

Ls : Solar Longitudes J2000.0
h  : Radiant height from the horizon (degree)
Lm : Limited Magnitude
Cl : Degree of cloudiness 

CHR = HR*Fa*Fb,  Fa = 1.6^(6.5-Lm),  Fb = 10/(10-Cl)
ZHR = CHR/(sin h)^1.5

Hourly Rate of Leonids (Every five minute)

Comment

14:00-16:00

Radiant place rised about 14:00(UT). Leonids meteor started before a few minutes from this time. The course of meteor at the time; about 14:00-16:00 was very long, so over 120 degree, from east to west.
This night, we moved to this place from another place to avoid cloudy weather. So, starting time of observation was too late, we could not count the number of these long meteors.

16:00-17:30

The meteors shower was starting already. The number of meteors increased slowly, but it was not the prediction of Asher, until this time. But the fire balls were many.

17:30-18:00

We watched sudden increase meteors. Three or five meteors appeared at the same time, we got excited. Hour rate(HR) got over 1,000 at 17:35, and over 2,000 at 17:45.

18:00-18:30

We felt the first peak of meteors around 18:00. HR was about 3,000. But a lot of meteors were not counted by us, the peak time might not be exact.
Second peak was around 18:20. This time was near the time of prediction by McNaught and Asher. But the peak was not sharp, we could not decide exactly the time of it.
Fire balls were not many so that time; 16:00-17:30.

18:30-20:00

Sometime, meteors was increase, but the number of whole meteors got decrease slowly.

20:00-

Twilight startet at 20:00. But many meteors were still watched. We felt the rate of blight meteors got increase. We regret that we could not observe the end of Leonids shower.

All Data of The Leonids Shower is here.

Photo of The Leonids Shower is here.

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