Hot News from Rick Nowell: Cranbrook College of the Rockies meteor camera picked up a very long and slow meteor graze or something re-entering the atmosphere. Slow, it takes 30 seconds to cross the sky. That happened on Tuesday 6 Aug 2013 at 4:52 am Mountain Daylight Time (or 10:52 Universal Time).
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This is a composite photo with the 30 seconds of video frames superimposed. This has been enhanced in IRIS by subtracting a camera dark frame to remove background hot pixels, offsetting 10 from the bottom amplitudes and applying an adaptive filter to remove some hiss, then taking a logarithmic stretch to bring up background stars, like Vega, Capella and Jupiter. (Altair seems too low when I compare to a starmap though). Note two reference points, a beacon to the North at Alt/Az (1.0, 3.1º), and another beacon to the NW at (3.0º, 309º).
The object kind of sputters and leaves a short smoke trail behind it. Fast at first, then slowing down. But no chunks falling off. It comes out of a thin cloud haze on the West, and vanishes in a band of clouds to the Northeast, into the morning twilight glow. But the sky appears clear in between.
Thin clouds could make it appear to sputter, but the sky appears clear overhead. Here in the attached SlowGraze_6Aug2013_600s.PNG I composited 600 seconds of video trying to enhance cloud structure. The object passes between two bright stars, Deneb and Vega. Capella is visible over the vent, but the rest of the dots are hotpixels. (See attached Mask_Boundary Hotpixels.JPG). You can see Jupiter rising in East, close beside the vent.
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(We put the camera beside the vent to shade it from light from some windows to the East.) Jeff Brower’s meteor camera in Kelowna also picked it up.
Esko Lyytinen in Finland tells Jeff that it has been uploaded to a number of websites, even one in Japan, and Jeff says it has received attention in the press.
For the video see:
http://skysentinel.nmsu.edu/allsky/viewer/798783
http://lunarmeteoritehunters.blogspot.jp/2013/08/bc-canada-long-duration-fireball-meteor.html
College of the Rockies, Cranbrook, BC, Canada 49°31’03″N, 115°44’37″W, 940m
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Hi all, Esko Lyytinen, of Finland, was once again kind enough to work on our images overnight. He has a preliminary result and he does emphasize he will be refining his modelling once he receives Rick’s cvs file for the event. That will hopefully determine if the meteor skipped back into skip or entered earth’s lower atmosphere. If we hear from the Albertan cameras, then we may have a much clearer picture of the final path. I did send Rick’s lat/lon/el to Esko so that will refine the original data. So with those caveats here is what Esko came up with. (I quote with his permission):
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Analysis from Finland
Jeff, I calibrated your camera by means of then stars. And I measured 15 mutually timed positions (of the fireball) in the one second images, with a time span of 16 s ( two missing in between, because not well measurable).
As to the Cranbrook camera coordinates, I may not have these as accurate. I have these: 0.427 km, 115.7 W , 49.6 N .
And as judged from the decimals count, these are only approximate.
I have these early results of the fireball. The radiant azimuth is 230.9 and elevation 4.2 . The reference horizon and meridian for these is 118.0 W, 49.5 N (not so fare from the beginning, rought 70 km after this) .
The entry velocity is 17.1 km/s.
It came in your camera at the height of 85.6 km and to Rick’s camera at 82.0 km. The last measured in your camera is at 64.4 km and Rick’s 58.7 km.
Because going away, the velocity near the end will not be accurately derived near the end. This data would even give some negative deceleration, which of course can not be true (but may actually be close to zero, mening quite a big meteoroid). If getting from Rick’s camera timed data also, might tell this better.
The most low “point” of the track would be maybe 10 seconds after last seen in Rick’s camera. It depends on the deceleration if the escaped back to space or not. Because no deceleration is visible in your data, I think it maybe probable that it did escape back to space. It may have been quite big (?)
As told, the precise coordinates of Rick’s camera are desirable. And if this would allow for internally timed could probably tell better on the velocity near the end. I see the video in the net, but if timed data does not exists in a more concise form, then the original video would be desirable.
Great work Esko and thanks from everyone at BCMeteors.net, from Jeff Brower, BC Canada