Regolith is a convenient app that approximatesseveral calculations for the position, visibility, phases and otherdata about the moon. The program is not meant to be an exactrepresentation of all the physics and mechanics that govern themoon; instead, Regolith is an aid to any observer, to quickly lookup important data about the moon in a sufficiently accurate manner.

"Sufficiently Accurate" is a direct reference to Jean Meeus.This program was written as an implementation of AstronomicalAlgorithms, originally developed by Jean Meeus: his incredible workin the field of Computational Astronomy has been the inspirationfor many works, including this one. While the calculationsperformed by Regolith are not meant to emulate NASA's ephemerides,Meeus' algorithms provide sufficient accuracy for the casualobserver and amateur astronomer and that is what you will findhere.

These are the functions that Regolith can perform:

* Detailed ephemeris of the moon for a given date and time,including observer's coordinate and time location
* Visualization of the phases of the moon in a calendar-like formatwith real pictures obtained from NASA's LRO site
* Real-time almanac for any given month (from the years 2000 to2050) including illuminated fractions
* Angle and date calculations to help you resolve your location andtiming
* All calculations can be scrolled into the past or thefuture
* All screens link to each other for convenience
* "Sufficiently Accurate" results are good to within 12 hours andto your location

To use Regolith you must first establish your location profile(otherwise, all calculations default to midnight - Greenwich) -this is called your "observatory". You may look up your city'scoordinated easily by searching google (for instance, "WashingtonDC coordinates" and simply enter the location angles provided indecimal form (e.g. 53.2366). Also check the box for DaylightSavings Time and enter your time offset from GMT (for instance, inthe eastern US this would be 5 hours - no sign needed for positiveoffsets, use negative sign for negative offsets).

After your profile is set, time of day is controlled by theEphemeris function thus, if you need to perform a calculation for aspecific time, go to the Ephemeris page and change the time there.Upon entering this page the clock is always reset to the exact timeon your device, for convenience.

Although we did not include a chart, the Ephemeris page willprovide you information about altitude and azimuth for the moon aswell as other positional data to help you locate it.