1 .TH ASTRO 1
2 .SH NAME
3 astro \- print astronomical information
4 .SH SYNOPSIS
5 .B astro
6 [
7 .B -dlpsatokm
8 ]
9 [
10 .B -c
11 n
12 ]
13 [
14 .B -C
15 d
16 ]
17 [
18 .B -e
19 .I obj1
20 .I obj2
21 ]
22 .SH DESCRIPTION
23 .I Astro
24 reports upcoming celestial events, by default for 24 hours starting now.
25 The options are:
26 .TP
27 .B d
28 Read the starting date.
29 A prompt gives the input
30 format.
31 .TP
32 .B l
33 Read the north latitude, west longitude, and elevation of the observation point.
34 A prompt gives the input format.
35 If
36 .B l
37 is missing, the initial position is read from the file
38 .BR \*9/sky/here .
39 .TP
40 .B c
41 Report for
42 .I n
43 (default 1) successive days.
44 .TP
45 .B C
46 Used with
47 .BR -c ,
48 set the interval to
49 .B d
50 days (or fractions of days).
51 .TP
52 .B e
53 Report distance between the centers of
54 objects, in arc seconds, during eclipses or occultations involving
55 .I obj1
56 and
57 .IR obj2 .
58 .TP
59 .B p
60 Print the positions of objects at the
61 given time rather than searching for interesting
62 conjunctions.
63 For each, the name is followed by
64 the right ascension (hours, minutes, seconds),
65 declination (degrees, minutes, seconds),
66 azimuth (degrees),
67 elevation (degrees),
68 and semidiameter (arc seconds).
69 For the sun and moon, the magnitude is also printed.
70 The first line of output presents the date and time,
71 sidereal time, and the latitude, longitude, and elevation.
72 .TP
73 .B s
74 Print output in English words suitable for speech synthesizers.
75 .TP
76 .B a
77 Include a list of artificial earth satellites for interesting events.
78 (There are no orbital elements for the satellites, so this option
79 is not usable.)
80 .TP
81 .B t
82 Read
83 ΔT
84 from standard input.
85 ΔT
86 is the difference between ephemeris and
87 universal time (seconds) due to the slowing of the earth's rotation.
88 ΔT
89 is normally calculated from an empirical formula.
90 This option is needed only for very accurate timing of
91 occultations, eclipses, etc.
92 .TP
93 .B o
94 Search for stellar occultations.
95 .TP
96 .B k
97 Print times in local time (`kitchen clock')
98 as described in the
99 .B timezone
100 environment variable.
101 .TP
102 .B m
103 Includes a single comet in the list of objects.
104 This is modified (in the source) to refer to an approaching comet
105 but in steady state
106 usually refers to the last interesting comet (currently Hale-Bopp, C/1995 O1).
107 .SH FILES
108 .TP
109 .B \*9/sky/estartab
110 ecliptic star data
111 .TP
112 .B \*9/sky/here
113 default latitude (N), longitude (W), and elevation (meters)
114 .SH SOURCE
115 .B \*9/src/cmd/astro
116 .SH SEE ALSO
117 .MR scat (1)
118 .SH BUGS
119 The
120 .B k
121 option reverts to GMT outside of 1970-2036.