Almanac opens with current mid-British Isles data. Instructions for use below.

Moon rises / sets:Sun rises / sets:

phaseMoon's age:
Morning planets: 
Julian Day:
Evening planets: 
 Add ISS passes?  Add phenomena of Jupiter?


 Country: Location: 
City: Time Zone:  hour(s) from UT

Date: 
Local Date 
& Time: 
Time:  UT Daylight Savings Time?
(If applicable, this MUST be checked!)

 Alt.Azi.Mag.SizePhaseRiseTransitSet
Sun  ---
Moon 
Mercury
Venus
Mars
Jupiter
Saturn

Key to the planetary data table above: The altitude (Alt.) and compass bearing (Azi.) give the object's position in the sky relative to your horizon. An object's altitude will be negative when below the horizon, zero when rising/setting, or +90° if overhead. Next is the apparent visual magnitude (Mag.); angular Size in arcseconds (arcminutes for the Sun and Moon); percentage of the disc illuminated by sunlight (Phase); and, for the specified location, the local times of Rise, Transit (appearing highest in the sky), and Set.
Note: the predicted rise and set times assume a flat horizon. If you have nearby hills or mountains, then the rising and setting times will be later and earlier, respectively.

How to use the Almanac: the program opens with the current sky for the central British Isles (54°N, 2.5°W), basing the Universal Time (UT) and calendar date on your computer's clock. The corresponding local date and time, day of the week, latitude, longitude and time zone are also displayed.

Under the selector at top right, you can determine the beginning and end of Astronomical, Nautical and Civil twilight, or the time at which bright Planets last or first appear.

You may also select an alternative location from the alphabetised pull-down Country and City menus, or enter a new Date (yyyy/mm/dd format) and/or Time (24-hour format hh:mm UT — use GMT in Britain), then click 'Calc' to update the Almanac. You may also step forward or backward in time by one minute, hour, or day by clicking the appropriate button. Clicking 'Reset' restores the program to the current date and time.

Crucial note: only select the Daylight Savings Time? button if appropriate for your chosen location and season!

International Space Station: select the Add ISS passes? button if you wish to display predictions of the space station's visibility for your chosen location over the next five days. It is computationally intensive, slowing the program if not required.

Jovian data: select the Add phenomena of Jupiter? button if you wish to display Great Red Spot predictions and details of eclipses, transits, occultations and shadow transits for Io, Europa, Ganymede and Callisto. As with the ISS predictions, selecting this option will slow the program if not required.