(meteorobs) NM Perseid highlights 1964-2004

[Norman W. McLeod III]

Originally posted in 2002 just before the Perseids of that year, I decided 
to update this and ship it out again:

There is sometimes a misconception around that Florida is too far south to 
see the Perseids well, based solely on lower radiant elevation.  Overlooked 
is the mitigating factor of much longer summer nights at the fringe of the 
tropics.  Northern regions have a short night with circumpolar Perseids 
visible all night, and observing takes place roughly from 10 PM to 3 AM 
local time.  From southern Florida the Perseid radiant doesn't rise until 
shortly after nightfall, and the extra dark hours give it time to rise 
almost as high as the northland can see before dawn.  Observing good rates 
is shifted to the later rough hours 1 AM - 5 AM, and the radiant is not far 
from the meridian.  I have never seen a Perseid maximum north of latitude 
27N or outside of Florida.

In 1980 George Spaulding in the UK had just seen an excellent Perseid 
shower when he suggested that I would do likewise in 1981.  His prediction 
was right on the money.  At that point I realized that a period of best 
rates seemed to span a quarter day.  Therefore the best Perseid showers 
would come every fourth year from a given longitude.  My peak results over 
the past 35 years singlehandedly bear this out.  The strong peak sputtered 
in some of the expected years, and there were a couple of anomalies.  But I 
am surprised at how well the scheme has held up.  Break the world into four 
quadrants to track the peak : America, Pacific, Asia, Europe.  The latter 
two would likely have a calendar date shift.  Below are the years in which 
I had excellent sky conditions for Perseids (unless otherwise noted) with 
the expected peak quadrant of visibility, together with the peak rate I 
actually saw from America.  Reports are abbreviated.


1964 - Europe - 42.  This hour started with 28 meteors (Perseids and 
non-Perseids) in 17 minutes, followed by zero in the next 10 minutes.  One 
single minute had 9 meteors, the ONLY time (away from Leonid storms) that I 
have ever seen that many in one minute.

1969 - America - 55,53, then 70% cloudy sky for 45, 27.  I was robbed the 
last 2 hours by clouds, missing a very strong display possibly at or near 
100/hour.

1972 - Europe - 41.

1973 - America - 29.  A nearly full moon had set mid-hour, allowing a brief 
period of semi-darkness.  It looks like an above-average year.

1974 - Pacific - 40.  A remarkable show with a moon two days past last 
quarter.  Rates rose strongly the final hour, indicating that I saw the 
beginning of the rise to the Pacific peak.  Long-enduring trains were 
numerous also.

1975 - Asia - 40.  Again the long-enduring trains were numerous.  After two 
years in a row, this situation has never recurred.

1977 - America - 51 (max + 1 day).  Robbed again by bad weather at max, it 
stayed very strong for an unusually long time so that I began the next 
night still above average.

1978 - Pacific - 69.  A repeat of the 1974 situation but after 
moonset.  For the first time I cracked 60/hour actually seen.

1980 - Europe - 50.  The peak was just ending, and it decreased further as 
my night progressed.  I declined to 39 the last hour.  This was a bizarre 
year all over the US, however, with reported rates very inconsistent from 
place to place.  Some observers still saw a very strong shower while others 
did not, and some saw a bright shower while others did not.  In my case, 
the Perseids were faint.

1981 - America - 89,92.  My big year finally arrived with the most amazing 
Perseid display ever.  The moon set in plenty of time for the best hours, 
and the Perseids exploded from 15 with the moon to 89 without.  Facing the 
radiant I had a torrent of faint Perseids pouring out of a single tight 
radiant, with a few bright ones thrown in.

1983 - Asia - 40; then 56,59 max + 1 day.  Here is the first anomalous 
year.  The Asian peak must have lasted much longer than usual for me to 
share in it.

1985 - America - 59 (sky 6.0).  The Perseids had strange blank periods of 
quarter-hours completely empty of meteors alternating with rich 
quarter-hours.  A potentially very strong shower was averaged down to just 
a good show.

1986 - Pacific - 46 a day after max.  This one does not fit in.

1988 - Europe - 73 last hour.  This one also does not fit.  The prior two 
hours were 42,49.  Something good happened while I was watching, a small 
rise followed by a strong show.

1989 - America - 62,61.  A rather strong peak that was expected.

1991 - Asia - 27.  The first of the enhancements predicted with the passage 
of the parent comet Swift-Tuttle in 1992.  This year began a series of 
lower Perseid  rates away from the peak which is still in progress today.

1993 - America - 17 (waning crescent moon, LM 6.0).  A very poor showing 
here with an enhancement over Europe instead.

1994 - Pacific - 28.  An enhancement came after my dawn, so I missed it 
again.  It appears the narrow enhancements have borrowed Perseids from the 
day before and after, leaving lower rates to see if one misses the best part.

1996 - Europe - 28, but 27 max + 2 days.  More of the same at lower levels, 
but a late little surprise thrown in.

1997 - America - 68.  After an 8-year wait, I finally got to see a good 
Perseid show again.

1999 - Asia - 19 (max minus 1 day).  Maximum was clouded out.

2001 - America - 25.  With a last-quarter moon and LM 5.5 this wasn't a bad 
showing, considering that other dark years were no better.  I have to 
consider the peak occurred here.

2002 - Pacific - clouded out.

2003 - Asia - only 3 in town with a setting full moon.  Poor rates 
continuing, contrast this night with 1984.

2004 - Europe - 54 early, then declining.  The late portion of the peak 
made it over here as I started.  Activity dropped off so much with the 
crescent moon rising that I gave up and quit an hour early.  Few bright 
Perseids also.

2005 - America - my expectation is to be near 70/hr to match 1997 and 
1989.  Possibly a good last hour in Europe as the rise to the peak begins.


Norman


Norman W. McLeod III
Staff Advisor
American Meteor Society

Fort Myers, Florida
nmcleod at peganet.com