Sounds like a Fastwalker. Terry
On Tue, Dec 29, 2009 at 3:57 PM, Horace Heffner <hheff...@mtaonline.net> wrote: > > On Dec 29, 2009, at 10:02 AM, Rick Monteverde wrote: > > 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. > > Yes, that accounts for distortion of the image. There is also atmospheric > scatter involved, and that might make an object look orange or red. It > makes snowy mountains here take on hot pastel colors - called Alpenglow. > This time of year the sun sets almost due west there. If the object was > ever in a direction approximately due north or south of you, i.e. on a line > perpendicular to the sunset location, then the altitude h I provided fairly > closely applies to the object for that time t in the table. If it was > mainly east or west then another calculation is needed. I would say > anything above 100,000 feet, or 18.9 miles, was probably not a military > jet, and certainly not a passenger jet. That altitude h corresponds to > about 22 minutes after surface darkness - to whatever degree such darkness > needs to be defined. From experience there, I know it gets dark pretty > fast in Hawaii after sunset - especially compared to here - where sunsets > can take a very long time. 8^) If you observed the object an hour after > sunset then I'd say it was well past the 22 minutes after darkness mark. A > general compass direction thus may be sufficient information for a > definitive answer. That far after sunset, an hour, taken even alone, is a > pretty strong indication it was not an airplane. > Best regards, > > Horace Heffner > http://www.mtaonline.net/~hheffner/ > > > >
