Input Values
Give Longitude
Give Right Ascention of Star Give Greenwich Mean Time (UT) |
Mathematics
GMST is same as GHA of Aries (Vernal Equinox). GMST is calculated from UT. LST is same as LHA of Aries (Vernal Equinox). LST = GMST + Longitude LHA = GMST + Longitude - RA LST = LHA + RA SHA in degrees = 360 - RA in degrees SHA in hours = 24 - RA in hours GHA = GMST - RA GHA = GMST + SHA GHA = LHA - Longitude
Astronomers uses Right Ascention (RA)
RA is measured eastward from the hour circle of Aries and expressed in units of time. Nautical Almanacs use Sidereal Hour Angles (SHA). SHA is measured estward from the hour circle of Aries and expressed in units of arc. RA and SHA are equivalent. |

Click on Button:

Output:

Julian Day at UT0:

Greenwich Mean Sidereal Time (GMST):

Local Sidereal Time (LST):

Local Hour Angle (LHA) of

Greenwich Hour Angle (GHA) of

Sidereal Hour Angle (SHA) of

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Last changes 2.6.2006