[meteorite-list] Leonids from southern California mountains
From: Matson, Robert <ROBERT.D.MATSON_at_meteoritecentral.com>
Date: Thu Apr 22 10:06:16 2004 Message-ID: <AF564D2B9D91D411B9FE00508BF1C86901B4E53C_at_US-Torrance.mail.saic.com> This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ------_=_NextPart_001_01C29025.9E553850 Content-Type: text/plain; charset="iso-8859-1" Hi All, Just got back from Lake Arrowhead, CA about an hour ago, and have been working my way through all the Leonid posts. The Readers Digest version: we had a great show! Not quite as good as last year, but I blame the moon for that. The air was very dry, and at 7000 feet you're above much of the haze, so while the Moon did cut the limiting magnitude to something like +5.5, it was darker than I expected. Went out to look for earthgrazers at about 11:45pm PST. Within a couple minutes I was rewarded with a nice long, lazy, green Leonid that left a brief train. Didn't see any others in the 15 minutes I was looking. Settled into the sleeping bags at 1:30am, positioning ourselves by a wall that did a great job of blocking the Moon. The rate was pretty low at this point -- perhaps 1 a minute. Things started to pick up noticeably around 2:15am, and by 2:30 the skies were quite busy, with meteors often appearing in doubles, triples and quads. My meteor count quickly ratched through 100, 150, 200 and I was expecting things to start to slow down as we passed the 2:30 predicted peak, but it didn't. It continued to intensify with the actual peak around 2:45. For five minutes around that time, the rate was a good 20 per minute. A surprisingly large number of near point meteors, and at one point I really got the "hyperdrive" effect with 6 simultaneous meteors eminating from the radiant in a starburst pattern! The falloff was not symmetric with the rise -- it was VERY abrupt. By 3:15, the rates were lower than what we were seeing at 1:30, and at 3:30 we called it a night with a Leonid occurring only once every few minutes. I estimate our peak rate was 1200/hour for a five minute window centered on 2:45am. We were only looking at half the sky (the wall blocking the half with the Moon in it), so the actual full-sky rate would have been 2400/hour. Definitely storm-level for a brief period. I can only imagine what it would have been like without a full Moon interfering. Best, Rob ------_=_NextPart_001_01C29025.9E553850 Content-Type: text/html; charset="iso-8859-1" <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> <META content="MSHTML 5.00.3315.2870" name=GENERATOR></HEAD> <BODY> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>Hi All,</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002></SPAN></FONT> </DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>Just got back from Lake Arrowhead, CA about an hour ago, and have been</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>working my way through all the Leonid posts. The Readers Digest version:</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>we had a great show! Not quite as good as last year, but I blame the moon</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>for that. The air was very dry, and at 7000 feet you're above much of the</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>haze, so while the Moon did cut the limiting magnitude to something like</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>+5.5, it was darker than I expected.</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002></SPAN></FONT> </DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>Went out to look for earthgrazers at about 11:45pm PST. Within a couple</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>minutes I was rewarded with a nice long, lazy, green Leonid that left a</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>brief train. Didn't see any others in the 15 minutes I was looking.</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002></SPAN></FONT> </DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>Settled into the sleeping bags at 1:30am, positioning ourselves by a wall</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>that did a great job of blocking the Moon. The rate was pretty low at this</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>point -- perhaps 1 a minute. Things started to pick up noticeably around</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>2:15am, and by 2:30 the skies were quite busy, with meteors often</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>appearing in doubles, triples and quads. My meteor count quickly ratched</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>through 100, 150, 200 and I was expecting things to start to slow down</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>as we passed the 2:30 predicted peak, but it didn't. It continued to</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>intensify with the actual peak around 2:45. For five minutes around</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>that time, the rate was a good 20 per minute. A surprisingly large number</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>of near point meteors, and at one point I really got the "hyperdrive" effect</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>with 6 simultaneous meteors eminating from the radiant in a starburst</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>pattern!</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002></SPAN></FONT> </DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>The falloff was not symmetric with the rise -- it was VERY abrupt. By 3:15,</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>the rates were lower than what we were seeing at 1:30, and at 3:30 we</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>called it a night with a Leonid occurring only once every few minutes.</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002></SPAN></FONT> </DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>I estimate our peak rate was 1200/hour for a five minute window centered</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>on 2:45am. We were only looking at half the sky (the wall blocking the</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>half with the Moon in it), so the actual full-sky rate would have been</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>2400/hour. Definitely storm-level for a brief period. I can only imagine</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>what it would </SPAN></FONT><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>have been like without a full Moon interfering.</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002></SPAN></FONT> </DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>Best,</SPAN></FONT></DIV> <DIV><FONT color=#0000ff face=Arial size=2><SPAN class=160173223-19112002>Rob</SPAN></FONT></DIV></BODY></HTML> ------_=_NextPart_001_01C29025.9E553850-- Received on Tue 19 Nov 2002 06:44:36 PM PST |
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