I wrote: " 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. "
I overlooked the fact that if the object were to the east of you then
the umbra plane would be even higher. It is only when the object was
to the west of you that there can be any doubt at all.
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
