Monday 15 August 2016

Astronomy - Yes, the Perseids Did Quite Nicely!

Astronomy - Yes, the Perseids Did Quite Nicely!

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Perseid Meteors by Alan Dyer, Aug. 12, 2016
On the morning of August 12, 2016, Alan Dyer shot many wide-field frames from Saskatchewan's Grasslands National Park, a dark sky preserve, and combined the frames with meteors into this composite.Alan Dyer /Amazing Sky Photography
Update August 13: Yes, the shower did briefly reach a zenithal hourly rate that may have been almost as high as 200 — timed for Europe. The International Meteor Organization's Video Network reports a one-hour outburst with a ZHR of 140 centered on 22:49 UT Aug. 11, then just a little later a narrow, a 26-minute outburst with a ZHR of 190 centered on 23:22 UT. "Activity of the background annual Perseid shower was higher by perhaps 20 percent over 2012 rates." See the IAUC Circularwith details (note that the times given there for the first two peaks should be dated Aug. 11, not 12).
Visual observations being reported to the IMO tell a similar story, though with less resolution; the two video peaks are blended in the updated visual activity curve as of this morning (August 13th EDT). There we also see a lower, broader, later peak centered around 2:15 Aug. 12 UT.
By the time North America rotated into good viewing position, ZHRs of 90 to 150 were being reported — only a little above normal. Rates dropped during the next 18 hours (three-quarters of an Earth rotation), judging by reports from the next three-quarters of the Earth to have their early-morning Perseid-watching hours.

Late-night skywatchers with a dark, starry view and a bit of patience were rewarded last night (August 11–12, 2016) with a fine showing of the annual Perseid meteor shower. The shower may or may not have reached twice its normal peak visual intensity, as predicted, judging from early tallies being reported.
Even if it did, very few people could hope to see the "200 an hour" that many news media were touting yesterday. That prediction referred to the standardized zenithal hourly rate: what someone's meteor count would be if the shower's radiant were at the zenith and if the sky were completely dark (6.5-magnitude stars visible). Most people's conditions fall far short of being that good.
The International Meteor Organization has been slow to get observers' data into its online activity curve for this year's shower, but that's not the IMO's fault! As veteran meteor observer Karl Antier posts from southern France, "Most of us have observed for nights now, and did not have time to send our visual results to the IMO, as daylight is used to recover and be ready for the following night. ;-)"
But Antier did post an account of his own this morning:
"Indeed, nice meteor outbursts occurred. The first one was quite short, and peaked at around 23:15 UT [August 11th]. . . some observers recorded [up to] 15 Perseids per minute, with many very bright Perseids.
Then, activity plummeted for 1.5 hours, and climbed again to decent rates from 2:00 UT until the end of the night (here in France, which is 3:30 UT).
"For me, the show was far more impressive than the 2011 Draconid outburst (ZHR ~300, but which occurred under Full Moon, with fainter meteors)."
Paul Roggemans of the IMO has posted a bunch of preliminary accounts at Meteor News:
The first impressions of the 11-12 August Perseids are being shared via Facebook. We give here some citations from observers who were lucky to watch the 11-12 August Perseid activity:

Koen Miskotte:
 “Brilliant Perseid outburst. 15 fireballs between [magnitude] –4 and –8. Three –8. Two peaks around 23:15 and possibly at 2:15 UT. Observed about 600 – 900 meteors. I don’t know. Maybe more…. We had unexpected very clear weather with limiting magnitude up to 6.8. Man man man what a show. The best one since 2001. . . .”
Casper ter Kuile: “Perhaps we did not observe such a nice fireball show but activity was much higher than expected. The first peak we acknowledge but as the radiant was quite low at the sky on La Palma this was not well defined. The second was much more obvious but if we can narrow it to 02h15m UT. But this is all very preliminary.”
Martin Popek [in the Czech Republic] postedimpressive [composite] pictures.
Mariusz Wisniewski posted on Facebook: “Perseids! Within minutes I could see even 7 meteors! We have seen very many bright meteors.”
Jure Atanackov: “Huuuge Perseid outburst observed!!! Rates the best since Leonid storm in 2002!!! Wow!!!!!”
Here are lots of pix.
The shower continues tonight (August 12–13) probably at lower levels, and for the next several days. But the waxing gibbous Moon is growing brighter and setting later. Tonight the Moon sets around 1:30 or 2 a.m. depending on your location. The best time to watch for meteors will be between moonset and the first light of dawn.

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