2008 09 09 The SPE Outbreak

Composite of SPE as seen at YLW


Jeff then contacted members of the British Columbia video meteor network to see if they captured the outbreak. Ed Majden in

Courtney, Ken Tapping in Penticton, and Ajai Sehgal, in Osoyoos reported they did have images of the outbreak.

While waiting for reports from the network observers Brower sent an e-mail to noted Finnish meteor researcher, Esko Lyytinen reporting the outbreak

and inquiring if any of the Finnish video network stations caught the outbreak. The Finnish video network was weathered out on September 9 but two stations (Timo Kantola and Esko Lyytinen) did catch a fireball from the shower radiant on 2008-09-07 at 23:10:05 UT.

Esko also report he had a peak for the outbreak period in his radio data as did David Entwistle in the U.K.  and Brower.

Esko asked Jeff to send some a composite image (jpg) from the outbreak. By using a graphics program Esko was able to push the contrast and the brightness of Brower’s still shot. Brower then use the same technique on his other fireball images. Using this enhancement method, Esko was able to bring out a dozen different stars, enough for him to calibrate Brower’s camera system. We then tried the same technique on Ken’s, Ed’s and Ajai’s images. When examined closely only Ken Tapping’s images were usable for a two station solution. Unfortunately, he other observers cameras were either out of focus or underexposed so no background stars could be pulled out of the noise.

With Tapping’s and Brower’s data Lyytinen began a concentrated effort for a two station triangulation solution and orbit determination for the outbreak.

Since the outbreak was unpredicted we had two major questions. The first question was does the radiant of the outbreak members coincide with the September Perseid Shower’s radiant.  The second question was the parent or source of the outbreak from a long period comet or a Halley type orbit (short period). The very short duration of the outburst is characteristic of a long period comet so the calculation of the period of the outbreak members would be critical in answering this question.

Lyytinen did all the calculations for us and we are very grateful for the long hours he put in on our behalf.

Esko first produced a back ray tracing using UFO Analyzer. The back tracing showed a tightly cluster point for the apparent radiant at Ra 47.1 and declination of +39.7 (see image below).

Lyytinen then began work on three fireballs mutually recorded by Ken and Jeff. Upon critical inspection Esko was forced to reject on of them due to the shortening of the image by the fish eye lens low to the horizon. The trail of the third meteor was too short to employ his method of analysis.

Lyytinen ran several iterations on the two fireballs and calculated orbital parameters for each. He also analyzed the Finnish fireball from the night before but noted he only considered the semi-major axis or orbital period in the averaging with the two from British Columbia. He also noted there might be “…some selection effect on the weighting of individual frame positions by the already known radiant.”

By using both use of the trail-image and the two station radiant data he was able to find nominal orbit parameters for the outburst. Esko’s best fit produced a geocentric radiant Ra 47.4 and declination of + 39.5 ( J2000.0). For a complete summary of his nominal orbit analysis see the image below.


Esko reported “I got the average of the inverses of semi-major axis (1/z) as 0.05454 ( 1/AU ). This corresponds a=18.34 (corresponding orbital period=78.5 y) . The standard error of the average of 1/z is 0.021 (even though from small number statistics).

The semi-major-axis and orbital, periods that correspond the 1/z values by one std.err at both sides are  13.24 AU and 48 years and 29.8 Au and 163 years.
So, the real uncertainty to the longer period side is practically to the parabolic orbit.”


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