By Muhammad Ali Channa

Moon Calculator (MoonCalc) is a DOS program which provides information relating to the position, age, phase, orientation, appearance and visibility of the moon for any given date, time and location on earth. It also provides the Julian Day Number, Magnetic Declination, time and direction of moonrise and moonset, interval between sunset and moonset, interval between sunrise and moonrise, date/time of astronomical new moon (conjunction), full moon, apogee and perigee and predicts the likelihood of visualizing the young moon from a particular location. MoonCalc provides Hijri calendar data including location dependent Hijri date conversion using predicted crescent visibility. Data pertaining to solar and lunar eclipse in any year are also shown.  The program can scan the globe at the start of any lunar month to find the location, date/time and direction of earliest crescent sighting using a variety of ancient and modern moon sighting criteria. The program is able to draw world maps (flat and spherical projections) showing areas of the globe where the young moon is likely to be seen.  

Graphical displays showing the position of the moon on a star chart and the position of the moon in a simulated local sky (horizon view or traditional circular sky-chart view) can be produced and printed out. A close-up of the near side of the moon (showing orientation of the moon's limbs and position of the lunar craters), correct for a given observation site, is also provided. This close up takes into account the effect of libration and 'limb shortening' (optional).  There is a choice of either topocentric/geocentric co-ordinates and apparent/geometric sunset. Correction for atmospheric refraction is optional. The program has a built in atlas database which stores latitude and longitude data of up to 1000 cities (ships with over 100 cities already entered). There are many user-configurable features