(meteorobs) Perseids 11 Aug 2009

pmartsching at mchsi.com pmartsching at mchsi.com
Tue Aug 11 11:37:49 EDT 2009


11 August 2009 06:55-08:55 UT (CDST 10/11 Aug 01:55-03:55 am)

Paul Martsching
McFarland Park 4 miles NE of Ames, Story County, Iowa, USA
Long: 93 deg 34 min W  Lat: 42 deg 05 min N  Elevation ~315 meters
Method: Visual; paper, pencil and talking clock

Showers observed:
Antihelion: none seen
A Capricornids: mentioned only if any seen during that hour
Kappa Cygnids: none seen
Perseids
Delta Aquarids: mentioned only if any seen during that hour
Sporadics

I got up at 11:15 pm CDST, looked at the infra-red satellite picture and noticed a good-sized patch of cloud to the NW of Ames.  When I went out the door I saw that the edge of the cloud was already visible in the NW.  So I went moth hunting for an hour, occasionally looking at the sky when I wasn't near bright lights.  Then I went out to my observing site and waited for the clouds to go away.  I saw several Perseids (mag +3 > +1) amongst the clouds while waiting.  The northern sky didn't clear till 01:55 local time.  Used black umbrella to block Moon light.  The first half hour was clear.  During the second half hour streaks and patches of clouds passing thru the bottom half of my field of view.  During the second hour several smallish clouds passed thru, but the sky was brightening.  While there was no actual fog, the dew point was so near the temperature that the bright Moon light was causing the limiting magnitude to worsen - so I finally quit and went home.  Of course train incidence and durations reduced due to bright Moon light - waning gibbous Moon.

The National Weather Service forecast for Ames for tonight had changed from "mostly clear" to "clear".  I hope this turns out to be true - it has been a great many years since it has been clear in central Iowa for the Perseid peak.

06:55-07:55; 66 deg F; dew point 65 deg F; wind West 3 mph; clear first half hour; 20% cloud cover second half hour = 10% for the entire hour; average limiting magnitude in the darkest area of sky ~5.0 - I could barely detect Eta UMi mag. 4.95; facing NNW 45 degrees; total teff 1.0 hour
Time    mag    type    comment
06:56    -5       PER   yellow; train lasting 6 seconds in bright Moon light; along E side of Cassiopeia
07:00   +1       PER   orange
07:07   +2       PER   yellow
07:10   +3       PER
07:15     0       PER   yellow; brief train
07:15   +1       PER   yellow
07:17   +1       PER
07:17   +2       PER
07:21   +1       SDA
07:27   +3       PER
07:34   +3       PER
07:42   +3       PER
07:42    -4       CAP   orange; I think was slow enough to be CAP and not ANT
07:54   +1       PER    orange
Capricornids: one: -4
Perseids: twelve: -5; 0; +1(4); +2(2); +3(4)
Delta Aquarids: one: +1
Sporadics: none
Total meteors: fourteen

07:55-08:55; 65 deg F; dew pt 64; wind NW 5 mph; "clear" some small patches of cloud passing thru = 5% cloud cover; "horizon haze" increasingly lit by bright Moon light; aver.lim.mag. ~4.7; facing NNW 45 deg; total teff 1.0 hour
Time    mag    type    comment
07:58   +3       Spor
07:58   +1       PER   fuzzball, without train or wake - no streak behind meteor; traveled 15 degrees
08:11   +2       PER
08:12   +3       PER
08:21   +3       PER
08:24   +1       Spor   orange
08:35   +3       Spor
08:39   +3       PER
08:42   +2       Spor
08:49     0       PER  orange
Perseids: six: 0; +1; +2; +3(3)
Sporadics: four: +1; +2; +3(2)
Total meteors: ten

No obvious fog on way home.





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