The Navigation Pac ROM for the HP-41 is apparently rare. The only offerings I've seen are an eBay auction a few months ago (dusty 41CX + wand + Nav Pac won for $169 -- wish I'd bid more aggressively!); and one MoHPC member had one for sale in classifieds.

I'd like to write a program for the 42S with the following data interface:

Inputs: date, time, latitiude, and longitude

Outputs: zenith angle, azimuth angle, rise time, set time for both sun and moon

I believe that the Nav Pac might offer some helpful code and ideas, but I don't know what it includes. My MoHPC CD-ROM set conatins neither a scan of that particular Pac (one of the very few that are missing), nor a code listing of the ROM.

One user program for the 42S in the MoHPC library calculates phases-of-the-moon and lists an astronomical reference.

Could anyone provide a Table of Contents listing for the Navigation Pac ROM, or give any other helpful info? Many thanks in advance...

-- Karl

Here's the table of Contents:

Great Circle Course and Distance
Great Circle Position
Rhumb-Line Course and Distance
Rhumb-Line Position
Great Circle Plotting and Voyage Planning
Dead Reckoning
Sight Reduction
Perpetual Almanac Stars, Sun Planets, Moon
Almanac Interpolator

Subroutines:
Sight Reduction Table
Calendar Functions
Greenwich Sidereal Time
Star Almanac
Fundamental Arguments
Astronomical Coordinate Conversions
Longitude to Latitude
Input/Output Routines

This manual will be on the next CD/DVD set which is what is currently consuming most of my time. I expect it to be ready quite soon.

Thanks, Dave! (and Luiz Claudio by e-mail). This looks like a good module to get. The "Almanac Interpolator" might provide much of what I want, except the nice 42S menu interface.

BTW, I misremembered a fact in my original post: The phases-of-the-moon program was written for the HP-41, not the HP-42. That also seems to be covered in the Nav Pac.

Good Morning Karl
As you mentioned it is very hard to get hold on a navigation pac. Approx. a month ago I was lucky to receive one. If it helps I could do a programlist printing for you. Let me know if you need copys of particular pages as well. Best regards Stephan

Having the Navigation Pac manual on the next CD ROM set will be irresistable incentive for me to upgrade. I have had the ROM for some time but have been unable to find a manual (even a copy). Thank you for all your efforts, Dave.