Specifications

50 AUTOSTAR CCD PHOTOMETRY
Where:
GMS
0hUT
is Greenwich Mean Sidereal Time at UT = 00:00:00.
Long is the Longitude of the observer’s site converted from
degrees to time from GMT.
UT is the Universal Time of the observation.
The factor 1.00274 is to convert UT solar time to UT sidereal time.
Note: Convert all times to decimal hours:
(Hours + minutes/60 + seconds/3600).
For example:
Kitt Peak National Observatory has a (geodetic) longitude of:
–111° 35m 52s or –111.59777778 degrees. This is equivalent to:
–7h 26m 23s or 7.423555556 hours West from Greenwich.
Long. (degrees) = 111.597777778 (degrees) * 24/360 (hrs/degree)
Long. (time) = 7.423555556 hours
If an observation was made at 4h 24m 16s (4.406154 hours) UT on
09 September 1990,
GMS
0hUT
= 23h 11m 52s or 23.18555556 hours
UT = 4.406154 hours
Thus:
LST = 23.18555556 – 7.423555556 + (1.00274 * 4.406154)
LST = 20.180227 hours
Creating an LST Table Using MICA Software
If one is to use a computer program to calculate this, it may be
desirable to create a look-up table of all values of LST at UT =
00:00:00 for a ranges of dates. While individual observation UTs
can be entered and LST determined, it is not practical to create a
table of such times.