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(meteorobs) Fwd: Obs. LANMA 16/17 Oct 1999 (ORI)




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Date: Sun, 17 Oct 1999 20:12:04 +0200 (CEST)
From: Marco Langbroek <marcolan@stad.dsldot nl>
To: meteorobs@jovian.com
Cc: dedalus@latrade.com
Subject: obs. LANMA 16/17 Oct 1999 (Ori)

What a beatiful night this was!

Due to a high above Scandinavia and a continental wind, the skies here have 
turned extremely clear and the air very dry. So, ideal conditions to go 
for a hunt targetting early Orionids. A table with data is at the end of 
this mail.

I started at 0:55 UT (2:55 local time) and to my excitement counted a Lm 
of +6.5 in both Taurus and Pegasus and even +6.6 in Perseus; in 20 years 
of observing from Voorschoten, I've seldom had such a deep limiting 
magnitude! Later this night, Lm slightly (but only slightly) dropped to 
+6.4, still extremely good for my location. The sky was star-spangled, 
the air tranquile and dry. Orion and Taurus and the winter milky way stood 
out very well, I could count 11 stars in the Pleiades easily. 
Temperatures were at 4 degrees Celsius, I reckon it must have been zero 
at toe-level. And in accordance with the good Lm, meteor rates were very 
good. In 3.10 hours effective, I observed a total of 62 meteors, of which 
12 were Orionids. All meteors have been plotted. Some nice and 
occasionally bright sporadics appeared (to name some of the best; fast 
yellow mag. 0 at 1:02 in -damned be the thing!- the Pegasus square; 
mediumfast mag. 0 at 2:46 in Auriga; fast mag. +1 with short persistent 
train at 3:51 in Auriga; fast mag. 0 at 4:13 on the Aur-Gem border). 
Thus, I enjoyed a very satisfying night. Orionids were modestly active 
and well recognizable, but no particularly bright ones appeared (best one 
a +2 with 1 sec persistent train at 2:55 in Aries). The first 
appeared 13 minutes after I started.

My data result in a Orionid ZHR of 5 +- 1; theoretically it should be 
around 6 (P. Jenniskens, A&A 287 (1994), 990-1013), so isn't that nice?!! 
There was a low Taurid activity, not particularly attractive although a 
nice long yellow mag. 0 appeared in Andromeda at 1:28. My data result in 
a overall Taurid ZHR of 2 +- 1 (theoretically it should be 2 -how nice 
again!). I also had two possible epsilon Geminids (although according to 
Marc's video data the stream might not exist), and one early Leo minorid. 

At 4:35 UT (6:35 local time) I stopped, because twilight was approaching, 
fatigue came down upon me and I noted that my mind started to wander from 
meteors to other attractive things (Lauren in Cairo). This was one of the 
most enjoyable nights I experienced lately. Since the good weather 
continues, I think I will be out again coming night, to see whether the 
Orionids are gradually catching on in activity.

Table with data below.

- - Marco Langbroek
  Dutch Meteor Society, the Netherlands

Obs.: Marco Langbroek     LANMA
Date: 16-17 October 1999
Loc.: Voorschoten, the Netherlands, 52d 07' N, 4d 28' E

UT          Teff   Lm    Ori  Tau eGem  Lmi  Spo   total  Ori ZHR
0:55-2:00   0.98   6.5    3    5    0    1    10     19    4+-2
2:00-3:00   0.88   6.4    6    1    0    0    11     18    8+-3
3:12-4:35   1.25   6.4    3    0    2    0    20     25    3+-2

TOTAL       3.10  <6.4>   12   6    2    1    41     62    5+-1

    
strm/mag.       0   +1   +2   +3   +4   +5      <m>
Sporadics       3    2    5   17    7    7      3.1
Orionids        0    0    1    2    6    3      3.8
Taurids         1    0    1    1    1    2      3.2
e Geminids      0    0    0    1    1    0      3.5
Leo minorids    0    0    0    0    1    0       -

>>>>>>>>>


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