Horace -
My sighting wasn't just after sunset, it was just after nightfall - total darkness. There was just a vague hint of fading light on the horizon, but the sky surrounding the object, which was relatively low in the southwest, was already black. I did find something on the after-sunset atmospheric distortion - they say add 6 arc minutes to the apparent semidiameter of the sun. I'll try to muddle through your figures in a little while. I sure appreciate the help, thanks. - R. From: Horace Heffner [mailto:hheff...@mtaonline.net] Sent: Tuesday, December 29, 2009 8:08 AM To: vortex-l@eskimo.com Subject: Re: [Vo]:Personal:Little help with UFO sighting? In case there is any doubt, the following is my final answer - unless of course I find other mistakes! 8^) On Dec 29, 2009, at 8:44 AM, Horace Heffner wrote: Hi Rick, Coincidentally, I saw something similar yesterday (Dec 28, 2009) around noon AKST, (about 11 orbits later) west of Palmer AK, but heading SW. It was one small finger width at arms length above the horizon. It had a periodic (about 10 second) flash to it, so I assumed it might be a booster, but strange it was heading SW, not SE or NE, or just S. Of course a U-turn is not a typical satellite maneuver, nor did I see that! The altitude h to the directly overhead sun midline is given by: h = r_earth * ( SQRT(1 + sin^2 theta) -1) Given time after sunset t we have: theta = (t/(8.64x10^4 s))*(2*Pi) radians = (t/(1440 min))*(2*Pi) radians Earth radius, r_earth, at Hawaii is about 3951 mi. Here are some numbers: t (min) theta (radians) h (miles) 1 0.00436331944 0.03760073165 5 0.02181659722 0.93976780755 10 0.04363319444 3.75594358 20 0.08726638889 14.973936498 30 0.13089958333 33.506081478 60 0.26179916667 130.1553394 90 0.39269875 279.3533269 Since the above is time after total sunset, you don't have to correct for the angular width of the sun. However, even total sunset is not good enough to black out an object though, due to light diffraction. Clearly not enough time, i.e. "shortly after sunset", passed to rule out an airplane. Best regards, Horace Heffner http://www.mtaonline.net/~hheffner/
