Our first installment is a basic star planner/finder for the 18 most visible stars used for celestial navigation, or simply good old fashion star gazing! The SHA and the Declination (DEC) for the stars are taken from the current year's Nautical Almanac. Click here for information on 1st Magnitude Stars.

To use this system, you must enter the date and time (24 hour basis) of your intended observation and the Latitude and Longitude of your viewing location. The time must be in Greenwich Mean Time (GMT). GMT equals your local time plus or minus your Zone Description. For example, if your Longitude is 75 degrees West, then the ZD is +5 (75 divided by 15 and "+" because of the West sign). Don't forget to adjust for day light savings time. Do not be overly concerned with perfect data. Remember, this is for estimating only, and to have some fun! For you landlubbers, use the best data at hand for your position.

The output of this program is the stars' altitude from the horizon (ALT) and the azmuth (AZN), ie. angle, from true north. A negative ALT value means that the star is below the observer's horizon.

Give it a try by clicking Star Finder.

The basic input and output for the four planets in the Planet Finder program are the same as the Star Finder. However, the planets' SHA and DEC are changing constantly on a daily basis. Therefore, we must input these values for each use of the Planet Finder. The planets' SHA and DEC values are found on the daily pages of the current year's Nautical Almanac.

Follow this link to the Planet Finder.

These programs is written in Javascript 1.0 and has been tested for the Netscape browsers 2.02, 3.01, and 4.01. The program also runs on some Microsoft IE browsers versions 3 and 4.

    E-mail comments to:   Norm Greisen

Reference: Astro Navigation by Pocket Computer  by M. J. Harris, 1989