Description:
This calculator has been developed primarily to extract the Greenwich Hour
Angle, GHA, of a celestial body from MICA (Multiyear Interactive
Computer Almanac) in a convenient way, but it can be used in combination with other
almanac software or printed almanacs as well.
Unlike the Nautical Almanac and ICE (Interactive Computer
Ephemeris), MICA only provides the Right Ascension, RA, of a
body which is the equivalent to the Siderial Hour Angle, SHA,
with the exception that RA is measured in hours (0 - 24) eastward from the
Vernal Equinox (first point of Aries) whereas SHA is measured in degrees
(0 - 360) westward from the vernal equinox.
SHA[°] = 360 15 · RA[h]
Converting RA to GHA requires Greenwich Siderial Time, GST, (also
provided by MICA), the Greenwich hour angle of the vernal equinox measured in hours
(0 - 24) westward from the Greenwich meridian (1h is equivalent to 15°).
GHAAries[°] = 15 · GST[h]
GHA = SHA + GHAAries
When using MICA, RA can be accessed through the following menus and submenus:
Calculate
Position
(select object)
Apparent
Geocentric
Equator of date
Greenwich apparent siderial time is available through:
Calculate
Time and orientation
Siderial time (App.)
LICENSE
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the license or any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License
(http://www.gnu.org/licenses/) for more details.
Henning Umland N 53° 20' 34'' E 9° 52' 00''
Check this web site for updated versions:
https://www.celnav.de/index.htm