Need information on time of dusk and dawn for Dallas Texas

I am in need of either an algorithm, a software program, a spreadsheet or a
list of the 'official' daily times of Dusk and Dawn for Dallas Texas for
2004. Can anyone help me?

My email is:

Terry

"Terry Locke" wrote in message
news:QNMHb.224891$_M.994714@attbi_s54...
I am in need of either an algorithm, a software program, a spreadsheet or a
list of the 'official' daily times of Dusk and Dawn for Dallas Texas for
2004. Can anyone help me?

Get a copy of The Astronomical Almanac.

Terry Locke writes:

I am in need of either an algorithm, a software program, a spreadsheet or a
list of the 'official' daily times of Dusk and Dawn for Dallas Texas for
2004. Can anyone help me?

First of all, there are astronomical, nautical, and civil twilight.
Which do you regard as the "official" one?

Second of all, the times depend on your exact location. The farther
east you are, the earlier the times will be. To estimate the size of
the effect, realize that the circumference of the Earth is about
25000 miles, and there are 1440 minutes in a day, which leads to about
17 miles per minute, though there is a latitude correction that needs
to be applied. The city of Dallas is bigger than 17 miles, is it not?

My ephemeris program displays astronomical, nautical, and civil twilight
for whatever location you choose, and there is a utility that allows you
to enter an arbitrary location into the database.

I was thinking of Civil Twilight (the one where the sun is 6 degrees below
the horizon). As for Dallas, yes it is larger than 17 miles however I was
looking for anything at all that would give me dusk to the nearest 5
minutes. Actually I live in McKinney which is about 30 miles north of and
5 miles east of Dallas.

This ephemeris program, where is it available from and what are the inputs
(long, lat)?

http://aa.usno.navy.mil/data/docs/RS_OneYear.html

Give this a shot... produces a big table

On Mon, 29 Dec 2003 03:01:05 GMT, "Terry Locke"
wrote:

I am in need of either an algorithm, a software program, a spreadsheet or a
list of the 'official' daily times of Dusk and Dawn for Dallas Texas for
2004. Can anyone help me?

My email is:

Terry