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Annotation of researchv10dc/dist/man/v4/man6/sky.6, revision 1.1.1.1

1.1       root        1: .th SKY VI 9/22/73
                      2: .sh NAME
                      3: sky \*- obtain ephemerides
                      4: .sh SYNOPSIS
                      5: .bd sky
                      6: .sh DESCRIPTION
                      7: .it Sky
                      8: predicts the apparent locations
                      9: of the Sun, the Moon, the planets out to Saturn,
                     10: stars of magnitude at least 2.5,
                     11: and certain other celestial objects
                     12: including comet Kohoutek and M31.
                     13: .it Sky
                     14: reads the standard input to obtain
                     15: a GMT time typed
                     16: on one line with blanks separating
                     17: year, month number, day, hour, and minute;
                     18: if the year is missing the current year is used.
                     19: If a blank line is typed the current time is used.
                     20: The program prints the
                     21: azimuth, elevation, and magnitude
                     22: of objects which are above the horizon
                     23: at the ephemeris location of Murray Hill
                     24: at the indicated time.
                     25: .s3
                     26: Placing a ``1'' input after the minute entry
                     27: causes the program to print out the Greenwich Sidereal
                     28: Time at the indicated moment and
                     29: to print for each body
                     30: its right ascension and
                     31: declination as well as its azimuth and elevation.
                     32: Also, instead of the magnitude,
                     33: the geocentric distance of the body, in units the program
                     34: considers convenient, is printed.
                     35: (For planets the unit is essentially A. U.)
                     36: .s3
                     37: The magnitudes of Solar System bodies are not calculated
                     38: and are given as 0.
                     39: The effects of atmospheric extinction
                     40: are not included;
                     41: the mean magnitudes
                     42: of variable stars are marked with ``*''.
                     43: .s3
                     44: For all bodies, the program takes into account
                     45: precession and nutation of the equinox,
                     46: annual (but not diurnal) aberration, diurnal
                     47: parallax,
                     48: and the proper motion of stars (but not annual parallax).
                     49: In no case is refraction included.
                     50: .s3
                     51: The program takes into account perturbations
                     52: of the Earth due to the Moon, Venus, Mars, and Jupiter.
                     53: The expected accuracies
                     54: are:
                     55: for the Sun and other stellar bodies
                     56: a few tenths of seconds of arc;
                     57: for the Moon (on which particular care is lavished)
                     58: likewise a few tenths of seconds.
                     59: For the Sun, Moon and stars the accuracy is sufficient
                     60: to predict the circumstances of eclipses and occultations
                     61: to within a few seconds of time.
                     62: The planets may be off by several minutes of arc.
                     63: .s3
                     64: Information about the program
                     65: may be obtained from its author.
                     66: .sh FILES
                     67: /usr/lib/startab, /usr/lib/moontab
                     68: .sh "SEE ALSO"
                     69: azel (VI)
                     70: .br
                     71: .ft I
                     72: American Ephemeris and Nautical Almanac,
                     73: .ft R
                     74: for the appropriate years;
                     75: also, the
                     76: .ft I
                     77: Explanatory Supplement to the American Ephemeris
                     78: and Nautical Almanac.
                     79: .ft R
                     80: .sh AUTHOR
                     81: R. Morris

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