NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Nautical Almanac
From: Paul Hirose
Date: 2018 Aug 11, 16:40 -0700
From: Paul Hirose
Date: 2018 Aug 11, 16:40 -0700
On 2018-08-10 23:30, Sean C wrote: > If you want higher precision/accuracy, I recommend the Multi-year Interactive Computer Almanac or [LINK: http://www.willbell.com/almanacs/almanac_mica.htm] "MICA" by the U.S. Naval Observatory. It's very slightly more expensive and 'only' good for dates between 1800 and 2050, but it provides many more types of data, at higher precision, than AstroNav. A disadvantage of MICA is that it displays zenith distance, not altitude. Also, MICA doesn't apply refraction. The only angle formats available are decimal degrees or degrees minutes seconds. Fortunately it's no great challenge to mentally convert seconds to tenths of minutes. In high precision work there's a nomenclature issue with MICA's "J2000" coordinates. In fact, as I confirmed with the USNO, the coordinates so labeled are really in the ICRS, which is skewed a few hundredths of an arc second from the J2000 system. If you're using MICA as a "gauge block" in software tests, it may appear that your code has not implemented the two systems properly.
