(meteorobs) Leonids 1974 and not only

Mikhail Maslov ast0 at mail.ru
Wed Mar 9 02:14:46 EST 2005


Sac> Mikhail -- Will this help you?

>>From SKY AND TELESCOPE
Sac> March 1976  Vol. 49, No. 3
Sac> Pages 193-194

Sac> Every report received from observers having dark clear skies indicated that 
Sac> the 1974 Leonid meteor shower was unexpectedly strong and one of the best since 
Sac> the great storm of 1966.  In Florida, Mr. (Norman W.) McLeod (of Punta Gorda, 
Sac> Florida) found the display "starling" during the predawn hours of November 
Sac> 17th.  "In the final hour," he writes, "I saw 40 Leonids, as well as four Tau
Sac> rids and 10 sporadic meteors.  About half of the 179 Leonids I saw during the 
Sac> 1974 display left trains; the longest one lasted for three minutes."

Sac> Seven members of the Norfolk Astronomical Society, Inc., watched the shower 
Sac> from Back Bay National Wildlife Refuge, Virginia Beach, Virginia.  Henry L. 
Sac> Miller reports that in 2 3/4 hours the team recorded 146 Leonids and 73 other 
Sac> meteors.  Seventeen of the Leonids were brighter than 1st magnitude, and all of 
Sac> them left trains.  One blue fireball's train remained visible to the unaided 
Sac> eye for eight minutes as it drifted slowly eastward.

Sac> On the night of November 16-17, a dozen members of Skyscrapers, Inc., of 
Sac> Rhode Island observed for eight hours, according to James LaLime.  Of the 192 
Sac> meteors they logged, 134 were Leonids; maximum activity apparently occurred about 
Sac> 4 a.m. (9h UT on Nov. 17).

Sac> Counts made on the morning of November 17th by Mr. (Bill) Gates (Albuquerque, 
Sac> New Mexico), Mr. McLeod, William G. Dillon (Springfield, Virginia), and Karl 
Sac> Simmons (Jacksonville, Florida) have been converted to zenithal hourly rates 
Sac> (ZHR).  The ZHR is the number of shower members a single observer would have 
Sac> seen in one hour if the radiant had been directly overhead.  The formula by 
Sac> which it is derived is explained on page 345 of SKY AND TELESCOPE for November, 
Sac> 1968.  From 10 ZHR's it appears that the 1974 shower reached a peak of 40 
Sac> Leonids per hour, comparible to the 1972 display (see page 127 of the February, 1973 
Sac> issue).

>>From "Handbook for Visual Meteor Observations"
Sac> International Meteor Organization, Edited by Paul Roggemans
Sac> 1989, Sky Publishing Corp.

Sac> Page 163
Sac> Leonids 1974    Nov. 17  USA (McLeod)   
Sac> Hourly rate/comment: 22 "astonishing display."

Sac> Leonids 1977    Nov. 17  USA (McLeod)
Sac> Hourly rate/comment: 13 "rates were poor."

Sac> It thus appears that the Leonids put on a very good
Sac> show in 1974 . . . not so in 1977.


Many thanks for this information, Joe. So, in 1974 American observers
noted unusual activity. Because computed peak was to be at 5 UT and
main observations were made some later, it could mean, that in
USA the declining part of outburst was observed. We still cannot say
how strong was this outbirst at all and when was its real peak time.
Nevertheless, I think we have good reasons to expect in 2008 and 2009
a good Leonid bright meteors and fireballs show, unfortunately under
full Moon in 2008.
In 1977 observers in USA reported no enhancements, but computed peak
time was to be at 18 UT, which favors for Asia, in America any
enhancements would be unavailable. Also meteors from such an outburst
in 1977 are supposed not be so bright on average.

Best regards, Mikhail




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