(meteorobs) Leonids 1974 and not only

[Skywayinc at aol.com]

In a message dated 3/8/05 11:34:08 AM Eastern Standard Time, ast0 at mail.ru 
writes:

> I'm very interested in references to Leonid activity in 1974 and 1977.
> It can help to make judgements about what can be expected in 2008 and
> 2009. 

Mikhail -- Will this help you?  

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

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

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

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

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

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

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

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

It thus appears that the Leonids put on a very good
show in 1974 . . . not so in 1977.
-- joe rao