Commit | Line | Data |
---|---|---|
6104700e RM |
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 |