Example Scripts

Here are a few samples scripts that show how to use PyEphem to perform simple tasks.

hale_bopp_ephemeris.py

The following script prints out an ephemeris.

import ephem

hb = ephem.readdb(
    'C/1995 O1 (Hale-Bopp),e,89.4245,282.4515,130.5641,183.6816,'
    '0.0003959,0.995026,0.1825,07/06.0/1998,2000,g -2.0,4.0'
    )

here = ephem.Observer()
here.lat, here.lon, here.elev = '33:45:10', '-84:23:37', 320.0

print "Hale-Bopp: date, right ascension, declination, and magnitude:"

here.date = ephem.date('1997/2/15')
end = ephem.date('1997/5/15')
while here.date < end:
    hb.compute(here)
    print here.date, hb.ra, hb.dec, hb.mag
    here.date += 5

Hale-Bopp: date, right ascension, declination, and magnitude:
1997/2/15 00:00:00 20:20:49.11 23:17:34.2 0.0
1997/2/20 00:00:00 20:39:29.29 26:38:56.6 -0.31
1997/2/25 00:00:00 21:01:27.07 30:15:40.6 -0.62
1997/3/2 00:00:00 21:27:38.03 34:02:02.9 -0.92
1997/3/7 00:00:00 21:59:04.35 37:47:03.6 -1.19
1997/3/12 00:00:00 22:36:38.57 41:12:54.8 -1.42
1997/3/17 00:00:00 23:20:28.94 43:55:38.2 -1.6
1997/3/22 00:00:00 0:09:11.83 45:30:21.2 -1.72
1997/3/27 00:00:00 0:59:34.63 45:41:07.9 -1.76
1997/4/1 00:00:00 1:47:38.29 44:29:10.8 -1.74
1997/4/6 00:00:00 2:30:23.60 42:11:38.0 -1.65
1997/4/11 00:00:00 3:06:42.92 39:12:15.1 -1.5
1997/4/16 00:00:00 3:36:55.11 35:52:30.5 -1.3
1997/4/21 00:00:00 4:01:57.98 32:27:45.2 -1.06
1997/4/26 00:00:00 4:22:55.70 29:07:19.0 -0.8
1997/5/1 00:00:00 4:40:44.44 25:56:03.3 -0.52
1997/5/6 00:00:00 4:56:08.73 22:55:55.0 -0.23
1997/5/11 00:00:00 5:09:42.34 20:07:08.7 0.05

jovian_moon_chart.py

This script prints out where the Jovian moons are around Jupiter for the next few days.

import ephem

moons = ((ephem.Io(), 'i'),
         (ephem.Europa(), 'e'),
         (ephem.Ganymede(), 'g'),
         (ephem.Callisto(), 'c'))

# How to place discrete characters on a line that actually represents
# the real numbers -maxradii to +maxradii.

linelen = 65
maxradii = 30.

def put(line, character, radii):
    if abs(radii) > maxradii:
        return
    offset = radii / maxradii * (linelen - 1) / 2
    i = int(linelen / 2 + offset)
    line[i] = character

interval = ephem.hour * 3
now = ephem.now()
now -= now % interval

t = now
while t < now + 2:
    line = [' '] * linelen
    put(line, 'J', 0)
    for moon, character in moons:
        moon.compute(t)
        put(line, character, moon.x)
    print str(ephem.date(t))[5:], ''.join(line).rstrip()
    t += interval

print 'East is to the right;',
print ', '.join([ '%s = %s' % (c, m.name) for m, c in moons ])

3/2 12:00:00                         g e     J   i                    c
3/2 15:00:00                        ge       J    i                    c
3/2 18:00:00                      g e        J     i                   c
3/2 21:00:00                     g e         J    i                    c
3/3 00:00:00                    g  e         J  i                       c
3/3 03:00:00                   g   e         Ji                         c
3/3 06:00:00                  g    e       i J                          c
3/3 09:00:00                  g     e   i    J                          c
3/3 12:00:00                 g       e i     J                          c
3/3 15:00:00                 g        ie     J                          c
3/3 18:00:00                 g         i e   J                          c
3/3 21:00:00                 g           i e J                          c
3/4 00:00:00                 g             i e                          c
3/4 03:00:00                  g              Jie                        c
3/4 06:00:00                  g              J  ie                      c
3/4 09:00:00                   g             J    ie                   c
East is to the right; i = Io, e = Europa, g = Ganymede, c = Callisto