Version 4

See FAQ/Help below.

Version 3

For support, information and answers to frequently asked questions regarding Version 3 (any release of version 3, including the latest which is 3.3.5) please click here.

Help Topics for Version 4.0

The program is designed to be as intuitive and as easy to use as possible. Assuming your Location is properly detected (see info below), the program should start up completely ready for you to use without any configuration.

However, questions do arise. Below we've covered the most common questions and areas that commonly need clarification. If you have any other questions please let us know. If you are confused, then likely other users are too -- and we'd like to clarify those questions.


When you first install the program it automatically sets and applies a default location. First, the program attempts to detect your approximate location using the IP address assigned by your Internet Service Provider. It uses that information to look up the matching latitude and longitude in a public database. This means the location selected will be for your ISP's location, which may or may not be your hometown. But it should be close -- meaning the calculations will be reasonably accurate.

There is a chance the lookup will fail, in which case the program will create a location for Greenwich, England.

You can edit the automatic/default location and/or add any other locations in the Location dialog box. Just click the "Location" or "Time Zone" text, or icon, in the top bar, and then either click "Add New", or click the pencil icon to edit an existing location. The location specified by the Latitude and Longitude must be contained within the correct Time Zone in order for calculations to make sense. Hence, time zone, latitude and longitude are all managed in the same dialog box.

In the dialog box, if you click the "Open Map" button, a world map will open up. You can click the map to select an approximate location anywhere on earth. Or, to be more precise, you can use this page and zoom in to your city, town or neighborhood using Google Maps.

Note: You can omit the "Name" of the location if you would rather see the latitude/longitude numbers displayed in the top bar, instead of the name.


The program should start up with the current date, but you can change it by clicking the Date & Time or icon in the top bar. You can also save any date in order to easily set and apply dates without having to type them in. Dates in the current era show normally, but if you apply a "BC" date it displays in the program with a BC designation. The historical date limit is currently around 4500BC.

Day Screen

The white arrows advance or decrease the applied date by whole days (24 hours) or whole hours. The blue square icons at bottom toggle between Moon and Sun data.

Month Screen

The program needs to know what time of day to use for each day's calculations, because many calculations change constantly. The default is 12AM (Midnight) but you can change it in the Settings dialog. To get to Settings, click the 3-bar icon in the upper right-hand corner of the program. Then select the time in the "Calendars Time of Day" dropdown field. The moonrise and set of course aren't affected by the time of day chosen.

If you hover over the moon image, you can see calculations for the Time of Day in settings. If you hover over the date (number) and/or acronym (e.g., "FM" for Full Moon, etc), you will see calculations for the exact instance of that quarter moon.

If you CLICK the moon, or CLICK the date/acronym, you will be taken to the Day screen for that instance in time.

Data Screen

This feature allows you to generate customized tables of moon data. It displays the table onscreen, but you can choose to Export it as a CSV (comma-separated) file which can be opened inside a spreadsheet program like Excel.

The Moon Data Table generator calculates data you choose (via the Column checkboxes) at your chosen interval (Daily or Hourly) throughout a specified period (Number of Results), starting from a certain date (Start Date).

A simple example: If you wanted to know the moon rise and set for the next 30 days, you would choose the Interval as "Daily"; enter the Start Date as today (click the clock or 'Today' button); type in "30" for Number of Results; select the Date, Moon Rise and Moon Set checkboxes; and then click Generate.

Click the "Edit" button to edit the table and regenerate a new one. Click the "Export" button to export the table as a CSV file.

The "Time of Day" field only matters if you choose a Daily interval AND if the data you want to show requires a precise instance during the day -- like Age, Percent of Full, Declination, etc; basically anything that changes during the course of the day instead of one-time events like Moon Rise or Set.

Also note that if you choose Hourly, certain calculations that don't change throughout the day or are one-time events like rise or set will repeat the same data over and over every hour until the table row reaches the next day.

That should be enough to get you started and allow you to play around with the various options to see the results.

The Quarter Moon Table also creates a table, but this time just with quarter moon events. For example, if you want to see the next 20 Full Moon dates, choose "All", a Start Date of today, and enter 20 in Number of Results. It automatically displays the time and weekday of each event.

The "Restrict to Date" checkbox allows you to restrict the results to only the selected quarter moons that occur on that date. For instance, to know when the Full Moon occurs on your birthday, or other significant event. These occurrences don't happen often, so the calculations have to do a lot of work and it may take a long time for a large number of events.

Other Topics/FAQ

If you're interested in using the program for hunting or fishing, you may be interested in the strategy explained on this page.

What is "Azimuth" and "Altitude"
Those numbers tell you the position of the moon. The Azimuth is basically the same as a compass bearing. It measures, in degrees, where the moon is on the horizontal plane, starting from grid north (not magnetic north) at 0 degrees and moving clockwise. For example, an Azimuth of 90 degrees means the moon is due east; 180 degrees is south; and 270 degrees is west. 360 degrees is equivalent to 0 degrees. The Altitude tells you how far up in the sky the moon is. For example, the moon could be oriented due west at 270 degrees, but that doesn't mean it is on the horizon. Altitude is measured from an assumed perfectly level horizon (this means that mountains or other obstructions may be in the way), at 0 degrees. An Altitude of 45 degrees is halfway up in the sky, and 90 degrees is straight up. Altitudes can be negative, which simply means the moon is below the horizon at that degree angle. So minus 90 degrees (-90) means the moon is directly "underfoot" (other side of the earth).

What is the "Brightness" calculation?
Technically, this refers to the "apparent magnitude" of the moon. The more negative a magnitude, the brighter an object is. The apparent magnitude of a Full Moon typically around -12, and a New Moon is typically around -2. The Sun has an apparent magnitude of -27.

What do the Civil, Nautical, Astro times for the Sun refer to?
Civil, Nautical and Astro refer to twilight, the period of time of varying light availability before the sun comes up or just after the sun goes down (sunrise and sunset). Calculations assume a flat horizon, clear weather and absence of other light sources like the moon. In the "Rise" column, Civil indicates the time when you can see significant detail in the landscape. In the "Set" column, Civil indicates when details of the landscape are no longer visible. Nautical twilight times are more about the very first light ("crack of dawn") or very last light ("nightfall"), the point when landscape details start to become visible or become hidden, and the horizon is barely visible. Astro is short for "Astronomical" twilight and it indicates when essentially all stars can be seen without light interference. For the detail-oriented person: Civil twilight occurs when the sun is 6 degrees below the horizon, Nautical is 12 degrees, and Astronomical is 18 degrees.

How is the Zodiac sign calculated?
It is the "Tropical" Zodiac (as opposed to Sidereal). And it is for the Moon (not the Sun).