The Celesticomp is the celestial calculator by which all others are judged. For neophyte celestial navigators, it introduces you to the concepts without requiring tedious and error-prone calculations. For experienced navigators, its saves time and reduces calculation errors. And for everyone, it eliminates the need to buy any almanac at all, because all the data you need is built in to Celesticomp's permanent memory: all 173 stars in The Nautical Almanac, the sun, moon, and all the visible planets. It does running fixes, averages LOPs and gives you a fix -- even identifies unknown bodies. It prompts you in plain English for the information it needs, and lets you check your input before calculating. It's very easy to use, and comes with a comprehensive instruction book. Fits in a shirt pocket and weighs just 3 ounces.