(meteorobs) 2005 Perseids

[Bruce McCurdy]

   After a frustrating summer of variable weather in western Canada, we got 
more of the same for the Perseids peak. We weren't completely skunked as was 
forecast at one point, but our window of opportunity was fairly short and 
closed real fast.

   A group of a dozen observers gathered at our Blackfoot observing site 
east of Edmonton late Thursday evening. I arrived with my son Kevin around 
11:50, a little behind schedule for my usual midnight to 5 a.m. session. In 
retrospect I wish I had arrived earlier.

    After a summer of clouds, perpetual twilight, clouds, light pollution, 
and more clouds, it was great to see the Milky Way in (most of) its glory 
wheeling straight overhead.  Limiting magnitude was a shade below 6.0. 
Viewing was mostly unobstructed until 1:30 when everything went to hell in a 
real hurry. Clouds rolled in, but more importantly, seemed to form in place 
above us. People started to take off between 2 and 2:30, but Kevin and I 
hung in for a last 15-minute miracle hole just before 3. But that 
disappeared as quickly as it developed and the rest of the night was a 
goner.

   The best Perseid was seen after we stopped counting, a bright fireball 
with an explosion point Larry and I estimated at -5 to -6. Limiting 
magnitude in that area of the sky was close to 0 at that point (we could 
barely see Vega), so how bright it really was is subject to speculation. 
This one left a train that lit the clouds for a few seconds. There were two 
others in the Venus range, one of which left a smoke trail low in the east 
that lasted for a good 15-20 seconds, with an associated overdense radio 
burst of about a minute.  There was a decent number of meteors in the 
low-minus magnitudes, and a few had trains in the 1-3 second range. 
Collectively, I would classify this year's Perseids as bright.

   Also noteworthy were two "clumps" of 6 or 7 meteors within half a minute 
or so. The better one featured mostly bright meteors surrounding the Great 
Square just before 1:00 MDT that punctuated about 15 minutes of very low 
activity.

   Here are the counts of the active observers, divided for the purposes of 
this message into Perseids and others.

UT          Bruce      Kevin          Larry      Arnold
            McCurdy   McCurdy    Wood     Rivera
---------------------------------------------------

0620-0630    8/1        14/1        8/1         8/1
0630-0640   13/1        12/1      10/1        9/3
0640-0650    2/3         3/1           -           -
0650-0700   10/0        12/0       7/0          -
0700-0710   13/3        10/3       8/2         8/2
0710-0720   12/3        12/3      15/5        13/4
0720-0730    9/2         7/1           -           6/2
===================================================

Total           67/13       70/10     48/9        44/12

Teff (hrs)      1.17        1.17      0.83        0.83

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

   Observed rates were just under one Perseid per minute for all observers, 
with enough other activity to raise those totals comfortably over the one 
meteor per minute level. Pretty decent considering this all occurred before 
local midnight and we were shut out of the prime hours between 2 and 5.

   My own count of 13 "others" included 6 Kappa Cygnids, 1 Alpha 
Capracornid, 2 North Delta Aquarids, 3 sporadic meteors and one from the 
anthelion radiant. In one remarkable bin (0640-0650 UT) I observed two 
Perseids and three Kappa Cygnids.

   This was my 18th consecutive August 12 of meteor observing. I have never 
been totally skunked, with Perseid counts ranging from as low as 4 to as 
many as 400+. Due to the limitations of the sky conditions I would rank this 
year's show as average, although it had the potential to be much better than 
that. But certainly well worth the effort.

   Bruce