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From: TerryMoselaol.com Date: 19 November 2006 19:25:48 GMT Subject: LEONIDS - PARTIAL SUCCESS Hi all, 1. The IAA's Observing Night + Leonid Watch at Delamont Country Park on Saturday night started well, following a good weather forecast, with crystal clear skies & very little light pollution. But after an hour or so we had a bad case of Cirrus Interruptus. Followed by an even worse case of Stratus Interruptus, which soon became Stratonimbus Interruptus, i.e. it started to rain. I decided to go home & wait for an improvement and/or get some sleep and set the alarm for the predicted 04.45 Asher - McNaught peak. It was still cloudy & raining at 02.00 when I went to bed. But ever the optimist I set the alarm for 03.45 to allow time to get up & out to a dark site if it did clear. But I awoke for a toilet break just before the alarm went off, & I checked the sky: pigs do fly! - through a totally clear sky! I had left all the observing gear in the car, so I dressed hurriedly & headed for the nearest dark-sky site, Big Collin, North of Ballyclare in the Antrim Hills. But as I approached I saw fog on the hill ahead (a common problem there at this time of year), so I turned & went towards a site between Belfast & Larne. Again, as I drove to the top of the hill, I went into fog, so I turned back into the valley & found a deserted lane. Quickly, out with the lounger, check the watch to start the observing session: "O5.25" - - - - 05.25!?!? It should have been about 04.15! - The battery on the alarm clock had chosen that night to fail, and it was over an hour later than I thought! So the Asher-McNaught peak had passed. Oh Deary Me! Or words to that effect..... Still, the sky was clear, so I observed anyway. And was rewarded with some good 'normal' or 'Ortho-Leonid' activity for a time well after the main traditional maximum. I only got 30 minutes clear sky before more Cirrus Interruptus, but in that time I got six nice Leonids, a Monoceratid, and a sporadic, plus more later (see below). The Leonids were spectacular - I had almost forgotten just how fast they are: even one streaking halfway across the sky takes less than 1/4 second! The magnitudes were +2, +3, 0, +1, + 1 & -1 with a 1 second train. The sporadic was mag 0, & the Monoceratid was +1. The cirrus thickened to stratus, but I could see a clear patch below it in the West, so I waited. While waiting I also saw two lovely Leonids through the last clear area in the sky to the NE (which hadn't been covered yet). One was a lovely -2 heading down below CrB, with a 2" train. Then one appeared right down at the NE horizon, ending in not so much a terminal burst as a terminal flash! It was just like a camera flash going off: I think the fact that it seemed to be heading almost directly away from me foreshortened the burst, so it appeared point-like. That was only about 5 degrees above the horizon, and so must have been nearly overhead from SW Scotland. And if it was -3 for me, at that distance, and at that low altitude, it must have been a real beauty for anyone there! I then got another 10 minutes with a 50% clear sky to the West, from 06.25 - 06.35 but the dawn was encroaching & I ended formal observing. But the best was yet to come: when driving home in the brightening twilight, I saw a real Leonid fireball low in the South, with a magnitude of about -5 ; brighter than Venus! The sky limiting magnitude was a reasonable 5.7, given that I wasn't that far from Belfast. That's too small a sample, over too short a period, to calculate a reliable ZHR but it does show that there's still good activity from the 'normal' Leonids even after the maximum. Funnily enough, on the previous evening (17/18), the night of the 'normal' maximum, I only saw two Leonids (+ 1 sporadic) in a 30 minute break in the clouds from 01.50 to 02.20, with a sky limiting magnitude of about 5.0. 2. I also got this report (the only other one so far) from IAA President Pat O'Neill: "Location: Belfast, N. Ireland (urban). 19 November. Time: 0415 to 0515 Atmospheric Conditions: Some thin clouds intervening Total Leonids: 5, (4 faint, one bright: mag -1) One bright Geminid (mag. -1) * Three observed within 2 minutes around 0450, coinciding with Armagh Observatory astronomer David Asher's prediction for increased activity around 0445. Patrick O'Neill Irish Astronomical Association" [ * Note: that meteor may have been from Gemini, but that shower does not officially start until 7 December. T.M.] DID ANYONE ELSE SEE ANY LEONIDS LAST NIGHT? - If so, please send me a report. And roll on the Geminids - the best of the annual showers, in mid December, with no moonlight this year! More later..... Clear Skies, Terry Moseley
Last Revised: 2006 November 20th
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