I have a question for you guys out there. I'm a very visual person so I will try to explain my question visually. First of all, if you aren't familiar with geosat flare season (yay! it's here already!), then read this posting (posting 1): http://www.satobs.org/seesat/Sep-2006/0029.html If geosats solar arrays face the sun, then the brightest flare should be when I am on or close to a line drawn from the sat to the sun. The problem with this is that I don't know how to get off this big ball we call the earth and the earth blocks the light to the sat. Observing at dusk helps because I am nearer the edge of the earth with respect to this line from the sun to the satellite whereas at midnight - not so good (but doesn't mean you can't see flares - these arrays aren't aligned perfectly and aren't perfectly flat). Although tonight I think midnight would be better. Now I live at lat 42N and so according to this (posting 2): http://www.satobs.org/seesat/Sep-1999/0002.html the best date to observe is around October 7. Reading posting 1 above it seems I can observe already. Okay - now for my question/point: If I could see the earth's shadow at geosynch distance, it would be a circle about 20 degrees in diameter. At this time in early September according to posting 1, the top of that shadow will just graze the location of all the geostationary satellites (for me at about -7 degrees). This is great because just before the satellites enter that shadow they should get bright. Now if you project my location on the earth onto that shadow at various times during the night, my position within that shadow will move from the right edge at sunset towards the middle at midnight and towards the left edge at sunrise so I would expect better flares to the right side of the shadow (sats move right to left with respect to stars) in the early evening and better flares left of the shadow in the early morning, right? Note that this line isn't horizontal nor is it parallel to the ecliptic but would be due east west along the declination line. However, I don't live on the equator or north pole. If you project my position on the earth back to that shadow again, there is a date when 42N right at sunset puts my projected point on the -7 degree declination line. If I lived on the equator then that date in the postings (sep 23) seems correct, but since I am north in the shadow, that date should be quite a bit before the date listed in posting 2 - probably around mid or late september rather than October 7 exactly. Does this make sense? Can someone come up with a table just like that in posting 2 that takes this into account? Of course the table should include the spring also. Posting 2 kind of takes this all into account when it metions that the satellite should enter the earth's shadow when that point in the sky is less than 20 degrees from the horizon. But it seems to give me the wrong 'ideal' date. - George Roberts http://gr5.org ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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