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(meteorobs) Fwd: First Perseids (LANMA July 18/19 obs.)
[
Apologies that this took so long to get forwarded. It was lost in my incoming
mail queue from "astrovacation"! By the way, Marco, be careful of those LOOOONG
headers of yours! For messages with many "To:" recipients, try resending the
message to 'meteorobs' as a separate email.
Clear skies!
Lew Gramer <owner-meteorobs@latrade.com
]
------- Forwarded Message
Date: Sun, 19 Jul 1998 10:42:20 +0000 ()
From: Marco Langbroek <marcolan@stad.dsl.nl>
To: Dutch Meteor Society -- Carl Johannink <cjohannink@netside.de>,
Casper ter Kuile <pegasoft@cc.ruu.nl>,
Erwin Ballegoij <ballegoy@wxs.nl>,
Guus Docters van Leeuwen <guusdvl@stad.dsl.nl>,
Hans Betlem <betlem@strw.leidenuniv.nl>,
Jaap van 't Leven <JVTleven@inter.nl.net>,
Jos Nijland <jnb@worldonline.nl>, Klaas Jobse <cyclops@zeelandnet.nl>,
Marc de Lignie <m.c.delignie@wxs.nl>, Olga van Mil <pvmilnwk@box.nl>,
Peter Jenniskens <peter@max.arc.nasa.gov>, Peter Bus <epbus@wxs.nl>,
Reinder Bouma <rjbouma@wxs.nl>, Robert Haas <delpsurf@pop3.cistron.nl>,
Eddy Echternach <zenit@astro.rug.nl>,
Edwin Mathlener <e.mathlener@astro.uu.nl>,
Tim Cooper <tpcoope@mweb.co.za>,
Robert Lunsford <lunro.imo.usa@prodigy.com>,
George Zay <GeoZay@aol.com>, R.A.Schievink@cnt.antenna.nl,
olech@sirius.astrouw.edu.pl, Jurgen Rendtel <jrendtel@aip.de>,
Sirko Molau <molau@informatik.rwth-Aachen.de>,
Erik Rossenberg <evanross@stad.dsl.nl>,
NAMN Meteorobs <meteorobs@latrade.com>, dvgevers@wxs.nl,
hugo@astro.rug.nl, kuiper@knmi.nl,
Natasja de Bruijn <natasja@stad.dsl.nl>
Subject: First Perseids (LANMA July 18/19 obs.)
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Hello All,
Last night has been very clear and so I enjoyed a fruitfull session on
the July meteors. This night featured amongst others my first Perseids of
this year. Also, this night was dedicated to the omicron (alpha) Cygnids.
Below my observational data, and an impression.
This was the first clear moonless night since June 21. A continuous
series of low pressure disturbances passing over last weeks temporarily
has given way to a ridge of high pressure and warmer air. A strong breeze
developed yesterday, and by nighttime this resulted in a very clear sky.
In the early part of my observations I counted Lm 6.4-6.5 in Aquila and
Draco, which is rare for my homebound location! Occasionally a small
patchy remnant of dissolving cumuli passed over at high speed, but they
were no serious problem. Near the end of the night, a combination of
advancing twilight, some haze developing and fatique arrising made for a
drop in Lm to 6.3-6.0 and a corresponding drop in meteor numbers. Venus
rose brilliantly in the southeast. There were no frogs this time, but the
bats were visible and audible. A very fine night!
Meteor activity was high. Some nice examples among them, but no real
bright meteors. The brightest was a +1 omicron (alpha) Cygnid in
northern Ophiuchus at 00:13 UT. The omicron (alpha) Cygnids were well
recognizable. Olech et al. of the Polish Comet and Meteor Workshop recently
got an enjoyable paper on this stream accepted by Astronomy &
Astrophysiscs. My first encounter with
this stream was in 1990, observing from Puimichel (S France), and it
really is a nice stream with nice meteors. I did not know of its
existence at that time in 1990, so they came as a surprise (I believe I
made an report on my observation published in WGN of 1991 or 1992). My
data from 1990 are part of Peter Jenniskens 1994 A&A curve for the stream.
This night as mentioned also saw my first Perseids of this year (3
members). The first was a nice +2 with 0.5 s persistent train moving from
Draco to southern Hercules at 23:22 UT. A second one, a +3 with a short
0.25 s train appeared at 23:34 moving from Vulpecula to Ophuichus. At
00:01 UT a +4 appeared in the same area.
A tentative calculation with my data results in an observed ZHR of 2.2 +-
1.0 for the omicron (alpha) Cygnids and 1.8 +- 1.1 for the Perseids,
which is in accordance with what you would expect for this date.
- -Marco Langbroek
Dutch Meteor Scoiety, the Netherlands
Obs: Marco Langbroek LANMA
Loc: Voorschoten, The Netherlands, 52d 07' N, 4d 28' E
Date: July 18/19, 1998
UT Teff Lm oCyg aCap dAqr-N dAqr-S Per Paus Spo
22:43-00:00 1.12 6.5 2 0 0 0 2 0 13
00:00-01:05 1.03 6.1 3 1 0 1 1 0 3
TOTAL 2.15 <6.3> 5 1 0 1 3 0 16 26
stream +1 +2 +3 +4 +5 +6
Sporadics 0 3 3 5 4 1 <3.8>
o Cygnids 1 0 2 2 0 0 <3.0>
Perseids 0 1 1 1 0 0 <3.0>
Capricornids 0 0 1 0 0 0
d Aquarids-S 0 0 1 0 0 0
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