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This might be old news to longterm list members, but it was new news to this
newbie:

A friend turned me on to BASNAV33, an old DOS program contained in a zip
archive file with 3 other files. These programs apparently were written by a
USPS celestial navigation person, Stanley L. Klein. They were written to
help CN students check their hand reductions.

"The following four files are included in archive (NAVSET33.ZIP):
1) BASNAV33.EXE
2) COSINE23.EXE
3) NAVPLN31.EXE
4) NAVSET33.TXT"

I found the complete zip file at http://ftp.linux.org.uk/pub/Navigation/.
See descriptions of the programs on that page at
http://ftp.linux.org.uk/pub/Navigation/DIRECTORY, where there are a bunch of
other free navigation programs too.

I ran the program (BASNAV33) on one of my Caribbean sights. It gave a very
different answer because the program does not allow me to specify ZD. The
Dominican Republic uses ZD +4 (AST), but the program calculates ZD using
longitude 68dW divided by 15d (ZD +5). So I got the right answer by tricking
the program, entering WT one hour earlier than what I measured. Then I got
the same answer as my hand reduction and CelestNav.

Advantages of the program:

- The program is handy for CN students because it follows the USPS SR-93
form, obviously similar to our CPS SR-90 form. So they can enter their data
the way they are used to.
- The program makes it easy to enter repeat sights for the same DR position,
date and time.

Problems with the program:

- It does not use exactly the same calculator formula for Hc. We use
meridian angle for Hc, but it uses LHA. However the principle is close
enough, and the answers are the same.
- Cannot specify Time Zone (ZD).
- The program does not print out its interim results, just Hc, Ho, LHA, a
and Zn. But that alone is useful for CN students who are trying their own
sights.

NAVPLN31 is nice for calculating solar phenomena in standard time zone
areas, but it did not work for my Dominican Republic sights because I could
not trick it around the time zone anomaly.

Of course modern commercial programs like Navigator, PocketPC and others do
all this in Windows more conveniently, but this set of programs is handy
because it follows the CN protocols, and of course they are free.

Jim Thompson
jim2@jimthompson.net
www.jimthompson.net
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