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(meteorobs) Oct 21 Observations and analysis - LMI?



It has been a while since I observed under good conditions, 
struggling against low clouds, haze, light pollution here on 
overpopulated Oahu. So, I decided to spend friday night on the top 
of Haleakala. What a pleasure to see again a near-perfect sky with 
the dazzling milky way, Gegenschein and Zbands! Of course 
moonlight began to interfere after 0130 local time, even more 
reason to go to the clearest skies possible.

I observed in 3 sessions, the first 1hr Teff just before moonrise, the 
2nd at 0230 local and the last 0.5hr before sunrise. Overall, I saw 
61 meteors in 2.5hr. The Orionids were not as impressive as I 
expected, only 17 total. The Anthelions were almost as numerous 
with 15. Also, very few bright meteors of any kind. Only 4 meteors 
were brighter than mag 2!

I had more difficulty than usual associating meteors with showers, 
because of the proximity of the ORI EGE and APX radiants, and all 
had very similar velocity! As a result, I believe my counts of these 3 
are less accurate than usual. In fact, I think there may actually 
have been a few more EGE than reported, because I may have 
placed too many "close calls" in the APX or ORI bin.

With this caveat in mind, I did a simple analysis of ZHR and found 
ORI somewhere between 10-15, compared with ANT tending to be 
<10. EGE ZHR were <5, but their raw counts were very low, and 
may have been underestimated, as stated above...

An interesting note: Leo Minorids activity was seen during the last 
0.5hr near dawn. Even though the raw count was low, I still get a 
surprisingly good adjusted ZHR of about 13 for this "unknown" 
shower! Has anyone else looked for this obscure radiant?

Aloha!
Mike Linnolt

REPORT FOLLOWS:
------------------------------
OBS: Mike Linnolt (LINMI)
DATE: Oct 21, 2000
TIME: 1000 - 1500 UT (12:00am - 05:00am HST Oct 20/21)
LOC: Haleakala NP, Maui, HI (20° 40' N, 156° 20m W)
ELEV: 3000m
Conditions: Sky clear. Temp 40F. RH <20%. Winds Moderate.
METHOD: Paper


Observing Periods Summary:
==========================

# Period(UT) FOV      Teff   F    LM     ORI EGE LMI ANT APX SPO
  ---------- ---      ----   -    --     --- --- --- --- --- ---
1 1000-1104  01h +00  1.00  1.00  6.6     7   0   0   7   5   6
2 1230-1333  03h +00  1.00  1.00  6.0     6   1   0   4   2   5
3 1427-1500  05h +00  0.50  1.00  5.9     4   1   2   4   3   4  

ANT = Anthelion radiant = NTA/STA
2 Breaks

Periods Detail:
===============

Period #1:
----------

Mag -3 -2 -1 0 +1 +2 +3 +4 +5 +6         elev  r  ZHR
--------------------------------------------------------------
ORI: 0  0  0 0  1  2  1  1  2  0 = 7      30  2.9 12.6 
EGE: 0  0  0 0  0  0  0  0  0  0 = 0
LMI: 0  0  0 0  0  0  0  0  0  0 = 0
NTA: 0  0  0 0  0  0  0  3  1  0 = 4      77  2.3\
STA: 0  0  0 0  0  1  1  1  0  0 = 3      77  2.3/ 6.6
APXn 0  1  0 0  0  0  1  1  1  1 = 5
APXs 0  0  0 0  0  0  0  0  0  0 = 0
SPO: 0  0  0 0  0  0  1  2  2  1 = 6

DEAD TIME: 4 min

Note: 

Period #2:
----------

Mag -3 -2 -1 0 +1 +2 +3 +4 +5 +6         elev  r  ZHR
--------------------------------------------------------------
ORI: 0  0  0 0  1  0  2  2  1  0 = 6      65  2.9 11.3
EGE: 0  0  0 0  0  1  0  0  0  0 = 1      56  3.0 2.1
LMI: 0  0  0 0  0  0  0  0  0  0 = 0
NTA: 0  0  0 0  0  0  0  0  1  0 = 1      65  2.3\
STA: 0  0  0 1  0  0  1  1  0  0 = 3      65  2.3/ 6.7
APXn 0  0  0 0  0  0  0  1  0  0 = 1
APXs 0  0  0 0  0  0  0  0  1  0 = 1
SPO: 0  0  0 0  0  1  1  0  3  0 = 5

DEAD TIME: 3 min

Note: Moonlight interference reduced LM.

Period #3:
----------

Mag -3 -2 -1 0 +1 +2 +3 +4 +5 +6         elev  r  ZHR
--------------------------------------------------------------
ORI: 0  0  0 0  0  0  1  2  1  0 = 4      86  2.9 15.2
EGE: 0  0  0 0  0  0  0  1  0  0 = 1      78  3.0 4.0
LMI: 0  0  0 0  0  0  1  1  0  0 = 2      32 ?2.5 13.0
NTA: 0  0  0 0  0  1  1  1  0  0 = 3      42  2.3\
STA: 0  0  0 0  0  0  0  1  0  0 = 1      42  2.3/ 19.7
APXn 0  0  0 0  0  0  0  0  0  0 = 0
APXs 0  0  0 0  0  0  1  2  0  0 = 3
SPO: 0  0  0 0  0  1  1  1  1  0 = 4

DEAD TIME: 3 min

Note: Moonlight slightly worse.

END OF REPORT.

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