[Prev][Next][Index][Thread]
(meteorobs) Re: NM Perseid highlights 1964-2001
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 33
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 - 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 - still in the future at this writing. All I can hope for is
a good last hour as the Pacific peak moves in. Question is, will I break
30/hour?
Norman
Norman W. McLeod III
Staff Advisor
American Meteor Society
Fort Myers, Florida
nmcleod@peganet.com
The archive and Web site for our list is at http://www.meteorobs.org
To stop getting all email from the 'meteorobs' lists, use our Webform:
http://www.meteorobs.org/subscribe.html