August 12/13 Meteors (and the Peak of the 2010 Perseids)
August 13, 2010 4 Comments
Last night marked the peak of the Perseids and they didn’t disappoint. Here in Tucson it was clear for yet another night. Quite a remarkable accomplishment considering it should be the middle of the monsoon. Some light cirrus did drift over the area from the south but it really wasn’t thick enough to hamper observing until the very end of the night.
I spent a total of ~2.25 hrs watching the shower spread over 3 separate outings. The plan was to get some sleep and then wake up early in the morning and drive to darker skies on the edge of town. Instead my wife and I decided to go out for an hour right before we went to bed. Though the radiant was very low we were hoping to catch a few atmosphere grazing Perseids. Even though the limiting magnitude was only +5.4 I counted 15 Perseids and 4 non-Perseids over the hour. That worked out to an average ZHR of ~80 over the course of the session. Pretty good.
After a bit of sleep I went back out for another 0.8 hours of observing. By now there was a lot of thin cirrus to the south. Usually the sky is much darker in the morning at my house but the cirrus kept the limiting magnitude at +5.4. During this session I counted 10 Perseids and 2 non-Perseids. This works out to an average ZHR of only 35. For the night of the peak, this is disappointing.
Deciding that I needed to get away from the city lights, I drove out to the edge of town where the limiting magnitude was +5.8. Luckily the cirrus hadn’t spread to the northern sky so I set up shop looking in that direction. The next 0.5 hours or so saw roughly a Perseid per minute with 33 Perseids and 4 non-Perseids being seen. This corresponds to an average ZHR of ~120 which is almost as good as you can expect from the Perseids. It will be nice to see if other observers noticed such high rates at this time (maybe Salvador and Bob).
Though many observations have yet to filed, preliminary results from last night suggest that the ZHR varied from 50 to 100 (see IMO ZHR Live).
Since I was forced by the cirrus to look directly at the radiant I did notice a handful of Perseids that appeared to radiate from an area a few degrees to the south of the radiant (near alpha Persei). I need to take a closer look at my video data to see if it confirms my impression.
My shallow wide-field and deep small-field cameras picked up 91 and 124 meteors last night of which 80 and 91 were Perseids. SALSA3’s 124 meteors is new personal single camera record for me. This beats January 2/3, 2009’s old record of 107 meteors during the peak of the Quadrantids.
If history is any guide, Perseid rates fall off rapidly after the night of maximum. ZHRs of “only” 20-30 should be expected tonight.
Obs Date(UT) Time TOT SPO ANT PER SDA BPE ERI KCG AUD SAL3 2010-08-13 08h 16m 124 25 2 91 3 0 1 0 2 ALLS 2010-08-13 08h 33m 91 2 0 80 2 4 2 1 0 VIST 2010-08-13 02h 17m 68 10 - 58 - (LM = +5.4,+5.8) SAL3 - SALSA3 camera in Tucson (Carl Hergenrother) ALLS - Near all-sky camera in Tucson (Carl Hergenrother) VIST - Visual observations from Tucson (Carl Hergenrother) SDG - Camera in San Diego operated by Bob Lunsford Time - Total amount of time each camera looked for meteors TOT - Total number of meteors detected SPO - Sporadics (meteors not affiliated with any particular meteor shower) ANT - Antihelions PER - Perseids SDA - Southern Delta Aquariids BPE - Beta Perseids ERI - Eta Eridanids KCG - Kappa Cygnids AUD - August Draconids