The Air Almanac contains the astronomical data required for air celestial navigation. The book provides the following data tabulated at 10-minute intervals to a precision of 1 arcminute: the Greenwich hour angle and declination of the Sun, Moon, and three navigational planets; the Greenwich hour angle of Aries; rise and set times of the Moon for a range of latitudes; and other data. Each edition also contains sky diagrams for each month; sunrise, sunset, and twilight tables; and positions of the navigational stars. The Air Almanac is available nine months in advance of its edition date.
Beginning with the 2008 edition, The Air Almanac is available only in PDF format. It is expected that those requiring a paper copy of certain pages will have access to a printer. Starting with the 2015 edition, users may download the entire almanac free of charge, although the CD is still available for purchase through the Government Printing Office (GPO). Two versions are available. The file airaYY.pdf is the entire publication in one large PDF file. The file airaYY_cd.zip also contains the entire publication in PDF format, but uses your web browser to navigate through the pages. The .zip file is virtually identical to the CD sold by GPO.
Editions of The Air Almanac Available for Download
- The Air Almanac Errata page contains information on errors in the publication.
- The history of The Air Almanac is found here.
- Ordering Information contains instructions on how to order The Air Almanac.
- The Depository Libraries around the United States retain a reference copy for each year of publication.