Hi Jason, I analyzed 15 of your Raduga 27 flash observations dating back to May 9th of last year and came up with a spin axis of RA 17.0218 hrs, Dec +79.1773 deg, and a cone angle of 86.568 degrees. I suspect the actual cone angle is within a degree of 90 degrees, but more observations are needed to refine the axis. Fortunately the precession of the axis would seem to be small, but another 4 months of data will be needed to quantify it with any accuracy. Since I didn't have peak flash times to work with, I used the midway points of your start and end times for each observation. (This definitely introduces some error because the flash track is not moving symmetrically with respect to your location). If my analysis is in the least bit accurate, then flashes currently start in NE Africa around 15:40 UT, slowly working their way northward. By 16:30, the southern-most portion of Saudi Arabia is reached. 17:15 - the border between Sudan and Egypt; Cairo about 30 minutes later. Crete and Sicily are crossed at 18:00, followed by Greece and Italy in the next 15 minutes. The peak for southernmost France should be around 18:15, with Switzerland only 10 minutes later. London and Belgium are on the flash centerline at 18:32, Edinburgh at 18:40, and southernmost Sweden at 18:45. All these times are for Wednesday, Feb. 23rd UT. One problem with this analysis is that it assumes that the reference points I used are all associated with the same reflecting surface. For example, if I use your observations from May 9th and June 4th, 1999, and Feb. 13th, 2000, I come up with a spin axis of RA 5.4566 hours, Dec -66.4579, and a cone angle of 81.2773. This axis may turn out to be more accurate since it involves the brighter flashes you observed on the morning of the Feb 13th rather than the dimmer evening flashes. More observations of the bright morning flash sequence (which is shorter lasting than the evening sequence) are needed to converge on the correct axis. The morning sequence is visible from all of Africa, Europe, Scandinavia and some of western Russia. Like the evening sequence, flashes begin in the south and work their way north (actually, more to the north-northeast). For Thursday morning, Feb. 24 UT, flashes start at the southern tip of Africa around 0:00, and Cairo about 2 hours later. Central France and Italy are on the centerline at 2:10, London at 2:15, Belgium around 2:17, Edinburgh at 2:22, southern Norway/Sweden at 2:30, and southern-most Finland at 2:40. It will be nice to firm up the behavior of this satellite so that it can be regularly predicted like Superbird A. By the way, I'm still working on ETS-6... --Rob ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Tue Feb 22 2000 - 19:49:13 PST