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(meteorobs) Re:Oct 22/23 Orionids continue faint + more



Had perfect conditions for a shrinking Orionid session, no clouds or fog at
all plus LM 7.4 sky again.  Same comfortable temperature as last night and
with a few mosquitoes.  Total time 2.32 hours and 77 meteors.
Two complete hours 426-626 EDT (826-1026 UT) had 21,21 Orionids; 14,8
sporadics; 36,33 totals.  Total showers 46 Orionids, 2 South Taurids, 1
North Taurid, 3 Epsilon Geminids, 25 sporadics.  Using 44 Orionids seen in
sky 7.0 or better gives average magnitude 3.50; table for -1 to +6 is
2,2,4,6,8,3,10,9.  Very faint again, and this time nothing brighter than -1.
Sporadics were far better than I've been seeing, before now only about 6/hr.
Taurids have been disappointing so far; I have done much better with them
during the Orionids in the past.  With the moon not interfering with Taurids
too badly in Nov I will be disgusted if max has rates of 2-3/hr like 1994 did.

I want to go out one last time tonight but a weak front is just north of
here kicking up some thin cirrus.  Will decide at the last minute.

The setting moon does indeed provide a spectacle in rapidly darkening skies.
I enjoy it every time, and it happens just as Bob described.  At 4 degrees
moon elevation I already had a 6.5 sky, right at moonset it was 7.0, then
within minutes fully dark at 7.4.  For the great 1981 Perseid shower I saw
just 15 Perseids in the hour with the moon setting.  Then a thick cloud
layer swallowed the moon one degree up, darkness swept in almost instantly,
and the sky erupted with Perseids.  The next two hours I was doing 90/hr,
and using the final 60-minute dark period I achieved a total of 100
Perseids.  I haven't come anywhere near that since. (Maybe in 1997?  If
eastern Europe had something good in 1996, it should shift 6 hours westward
next year.)

Most of the time I face south at 70 degrees up and let the sky drift.  This
week I faced the Orionid radiant full time.  I usually note a star each hour
to look up coordinates for later.

Superb eyesight allows me to see meteors shorter than 10' of arc.  That's an
easy length for me to detect.  On the last visit to the optometrist when I
needed new glasses, I had no challenge in reading the 20/20 line with
corrected vision.  He put up the 20/15 line, still no challenge.  Then he
put up the 20/10 line and asked, "Can you read that?"  Now I had to think
before speaking each time, but I got all these right as well.  So I must be
around 20/8 corrected.  I don't see how my glasses would be doing any
magnifying.  Lenses are negative for nearsightedness, and when I lift them
off to defog them the sky shrinks in the glass.  Even without the glasses I
can see better than 6.0.

In the ongoing collection of data from fabricated radiants, I pick a star
well-removed from known radiants and note what comes from within 2 degrees
either side of it.  This week I have been using Kappa Orionis.  All sporadic
meteors I am classing as fast, medium, or slow.  This is an attempt at
determining a very rough  velocity, not just degrees per second.  Take into
consideration together the distance traveled and the duration.  A very short
meteor that is 0.3 second or less is definitely a fast one, 0.4 to 0.8 I
consider medium, and greater than 0.8 is slow.

Very often I have had my best sporadic rate in the second hour before dawn,
then a pronounced slump the final hour.  That's not the way it "should"
happen, and I haven't heard any reasonable explanation for it.  Even Olivier
(AMS founding director, 1911-1975) was aware of it, and he couldn't explain
it either.

The active observers of the late 1970's were separately mentioning a few
swift meteors coming from Auriga during the pre-Orionid max nights, and I
was aware of them myself.  I was always facing south so never achieved a
plotted radiant.  Seems to be located near the Kids, the group of stars near
Capella.  Drummond published a paper around 1983 about this, nominating the
Delta Aurigids as an addition to Cook's list.  It is interesting that this
shower is now noticed in September as well.  I failed to pick it up in 1971,
1974, and 1980 Sept observing--my best years for that month.

During the 1975 Perseid watch in the Keys some of us went to a second site
40 miles away (Lower Matecumbe Key vs the Bahia Honda bridge).  I looked for
some correlation for rich periods and slow periods in our data from the two
sites, and could find no similarity at all.

Norman
Fort Myers, Florida


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