In article , Scott wrote:
Sniz Pilbor wrote:
is there a general method to find nautical twilight begin/end times if
you know civil twilight begin/end times as well as lat/long (and
elevation if that matters)?

any help will be much appreciated...

I don't know if it's a general method, but I use:

http://directory.google.com/Top/Scie...un/Sunrise_and
_Sunset_Times/

and the links therein.

The site I mentioned the other day will also do this sort of thing.
Have a squiz at

http://www.ga.gov.au/nmd/geodesy/astro/sunrise.jsp

and you will see options for various standard definitions of twilight,
as well as the usual sunrise/sunset.

There is also the option of specifying your own value of Zenith
Distance; which can be useful if, for example, you're interested in
photoperiod effects.


Cheers, Phred.

--
LID