(meteorobs) Orionid Summaries HALWA at NJAA

[meteoreye at comcast.net]

This is the first of 4 posts today with more detailed summaries of the observations for the nights surrounding the Orionid peak.

This information applies to all 4 mornings.

Observations were made at the NJAA Observatory. 74:53:54 W 40:40:52 N Elev 253 meters.
All data recorded on audio tape, so no data recording downtime. Any discepncy between elapsed time and Teff is due to the occasional "natural" break.

Shower association was made using an alignment cord and knowledge of the shower velocity. This is especially important since many of the showers are close together (such as the two Taurid radiants),  in the same general area close to the moon (ORI,EGE,XGE) or at the edge of the FOV (LMI).
I found it an essential tool in accurately identifying many shower members.

In general, my field of view was between SSE and SSW at ~ 60 degrees elevation. When the moon was directly overhead I lowered that somehwat and shifted a bit away from the moon in Azimuth.

All meteor times and magnitudes were recorded to the minute, more detailed intervals and magnitude distributions are available on request. At the end of each I will include a link to the data in the IMO online database which includes shorter intervals and full magnitude distributions.

F=1.00 for all observations. On the occasions where there were clouds, they were very thin cirrus and only caused a reduction in LM, and are reflected in the recorded LM numbers.

Shower XGE is # 64 from Sirko Molau's 2006 analysis of IMO video data (velocity 59 km/sec).

 A "/" in shower data for LMI indicates that the radiant was either below the horizon of in a position where it could not be monitored even using the alignment cord.

===========================

UT Date October 20, 2008 (Observations 00:06-6:02 EDT)

Showers RA Dec
ORI 094  +16
NTA 038  +18
STA 040  +12
EGE 104  +27
LMI 158 +39
XGE 107 +11
(XGE-None observed this morning so omitted from summary below)

UT Time     Teff    LM ORI NTA STA EGE LMI SPO Tot Met/Hr Ori/Hr
0406-0537 1.45 +5.70   8     1      1      2      /      3      15   10.3   5.5
0537-0637 1.00 +5.67   6     1      1      0      /      2      10   10.0   6.0
0637-0737 1.00 +5.63   6     1      1      0     0      4      12   12.0   6.0
------------
0902-1002 1.00 +4.90   9     0      0     1      0      1      11   11.0   9.0
-----------------------------------------------
0406-1002 4.45  +5.49  29   3     3      3      0     10     48   10.8   6.5

This was really a story of three nights in one. The first 1.45 Teff, from 0406-0537 had exceptionally clear skies considering the 62% illuminated moon rising near the radiant. I have observed onder worse conditions on many moonless nights. This period featured very dim Orionds. Their average magnitude was only +3.63! The brightest was only a +1.5, while the largest bin was +4.

After 0737, the charachter of the Orionids changed dramatically. The average magnitude of the Orionids for the next 2 hours was +0.67! This included 3 0 mag or brighter and the dimmest only +3. The largest magnitude bin was +2.

At the end of this period, a thicker layer of cirrus overspread the area which, being lit by the moon, stopped observations.

The final hour before dawn was with the moon nearly ovserhad and hazier skies, so the LM was very bad. Still, there was a good number of Orionids, with a peak of 7 occurring in the 15 minutes between 0937 and 0951. Average ORI mag for this hour was +2.33

Totals

48 Total Meteors  (10.8/Hr) Avg Mag +2.39

29 ORI (6.5/Hr) Avg Mag +1.98
3 NTA (0.7/Hr) Avg Mag +1.5
3 STA (0.7/Hr) Avg Mag +2.5
3 EGE (0.4/hr) Avg Mag +1.2 (First meteor of night was a long -3 EGE)
10 SPO (2.2/Hr) Avg Mag +3.00

Full IMO reports can be viewed here:

First 3.45 Teff
http://umdb.urania.be/v2/obsview/view.php?id=4100 

Last Hour Teff:
http://umdb.urania.be/v2/obsview/view.php?id=4101

Wayne