Astronomical Almanac 2021
LXXVI volume of the Astronomical Yearbook for 2021 in electronic format (pdf) is a continuation of the previous editions in unchanged form.
The electronic edition of the almanac is suplemented by a traditional printed version in shortened form, as well as an on-line version. At the moment the Astronomical Almanac "On-line" includes two calculators. The "Calculator of the Apparent Position of stars" allows to calculate the apparent position of all stars of the FK5, FK6 and Hipparcos catalogs, in the FK5 System as well as in the IRS. The "Calculator of Mean Posiotion and Besselian Numbers" alows to calculate the apparent position in the FK5 system, in an 'old fasion" way, i.e. using mean positions of stars for mid-year epoch and the associated Besselian Numbers.