NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Marcel Tschudin
Date: 2005 Aug 5, 00:33 +0300
Hello Frank
You are right, in realty it would only be some approx.
hundred lines of programming. May problem however is that I lost during more
than 30 years after leaving university the know how on how to do. What 30 years
ago would probably have been a little problem became now a big problem. That
is why Im looking now for the easy way, i.e. an analytical
approximation
You wrote:
Assuming your goal is to
create accurate simulated views of landscapes (is it??), that's probably the
best way to proceed.
No, the program is just to calculate some astronomical
data, but those with a higher accuracy than normally available. I know there
have been done very good simulations of landscapes even in very realistic moon
shine conditions.
You wrote:
Then you can include as much
detail as you want --temperature inversions, pressure gradients, anything-- and
you can calculate extinction at the same
time.
If I
remember right refraction is caused to a large extend by the
temperature gradient, i.e. the 6.5°C/1km for the first 11km of the standard
atmosphere
and being able to calculate extinction for altitudes below +5°
altitude would also be of interest for some other aspects; further more I also
would be interested in how to calculate the visible brightness density of the
sky (relative to the position of the sun)
Yes, it all could be calculated. But
as I mentioned, my know how has in the last 30 years deteriorated
I therefore
would need now very good text books with program descriptions and sample
calculations.
But for the moment I really would be very happy just to
be able to calculate refraction values for negative
altitudes
