Re: interesting pic for a classroom exercise?

[Stefan Jeglinski <jeglin@4PI.COM>]

> By a lucky coincidence, last week, just after I bought a solar filter for my
> little Meade scope, I saw the same thing. No more than a couple of seconds
> after I found the sun, a 737 flew in front of it. One of thowe WOW
> experiences.

Well, now I'm glad I didn't ask my followup question for experts:
"what is the likelihood of seeing such a thing?" :-)


>  My question for the group, however, is why the exhaust trails
> are so opaque. They were in what I saw, just as in this photo. I looked at
> the plane a few seconds later, and the it was not leaving visible contrails.
> Refraction phenomenon, maybe?

This is a better followup question than mine :-)

At any distance, the only reason that one would see the jet itself as
anything other than a silhouette is because of reflected light into
the eye (the ultimate source of which is the scattered light of the
atmosphere). Likewise the white contrails seen with a high altitude
jet, no? Because of the brilliance of the sun I suppose and the
absence of scattered atmospheric light in such a picture, why would
the contrails -not- be silhouetted?

There's probably more to this one than I'm surmising... -good- question.


Stefan Jeglinski