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Subject: Jupiter satellites
From: Herbert Prinz (hprinz@XXX.XXX)
Date: Fri Oct 04 2002 - 17:28:55 EDT
I see there are some early-risers on this list. Here is the ouput from a
little planning tool that has helped me setting my alarm clock over the
past few years.
A. Potential observations of Galilean Satellites at Greenwich in October
2002
mm-dd UT1 sat phen ev RAsun RAjup DECjup AZ Hsun
Hjup
10- 1 02:22:56 I EC D 12.47 8.98 17.59 80 -31.9
14.2
10- 5 03:18:20 II EC D 12.72 9.03 17.42 93 -26.1
24.7
10- 8 04:16:26 I EC D 12.90 9.06 17.29 107 -18.5
35.1
10-12 05:52:50 II EC D 13.15 9.10 17.13 138 -4.6
49.4
10-15 06:09:56 I EC D 13.34 9.13 17.01 147 -2.7
51.9
10-17 00:38:20 I EC D 13.45 9.15 16.94 70 -46.2
6.0
10-24 02:31:44 I EC D 13.89 9.21 16.70 97 -37.6
26.9
10-30 00:17:56 II EC D 14.27 9.25 16.52 75 -51.5
9.3
10-31 04:25:14 I EC D 14.35 9.26 16.48 131 -22.9
46.3
B. Potential observations of Galilean Satellites at WAS observatory in
October 2002
mm-dd UT1 sat phen ev RAsun RAjup DECjup AZ Hsun
Hjup
10- 4 07:54:08 III EC D 12.67 9.02 17.45 85 -33.3
21.1
10- 6 09:48:02 I EC D 12.80 9.04 17.37 106 -13.2
43.5
10-12 05:52:50 II EC D 13.15 9.10 17.13 70 -52.4
3.4
10-15 06:09:56 I EC D 13.34 9.13 17.01 75 -51.5
8.3
10-19 08:26:56 II EC D 13.59 9.17 16.86 99 -30.9
36.3
10-22 08:03:26 I EC D 13.78 9.19 16.76 97 -35.7
33.8
10-26 11:00:56 II EC D 14.04 9.22 16.62 155 -3.6
63.5
10-29 09:56:56 I EC D 14.23 9.25 16.53 131 -16.1
57.3
The above two tables list eclipses of the Galilean satellites that might
be observable from the places named in the header. (Greenwich is a place
where they once had an important observatory and WAS is theAstronomical
Society of Westport, Connecticut, N41/W73, where they still have an
observatory.) If you don't live too far from either of these two places,
this will give you a rough idea of what you can see. Other places on
request, preferably offline.
I have listed only eclipses, because only those are suitable for
longitude determination. (But transits are actually more fun to watch.)
As it happens, no eclipses for sat III and IV are observable this month
from either place, and for the other satellites you can see only their
beginnings (D stands for debut) at this time of the year.
This is only a planning tool!! Listed are the mid-times between internal
and external contact on entrance into, or exit from, umbra. For detailed
timing information on the individual events as well as for entrance/exit
into/from penumbra you should consult the IMCCE ephemeris directly. You
may see the satellites starting to fade ca. 2 minutes before the time
listed in my table. Be at the telescope early and make sure you are
looking at the correct satellite.
The table entries should be self explanatory. Times are given as
Universal Time. RA stands for right ascension. RAjup and RAsun help
understanding the geometry of the situation and why you see certain
phenomena and not other ones. The azimuth is that of Jupiter. H denotes
altitude. Not knowing anything about an observer's local situation, I
chose H= 0d as as a cut-off altitude for both, Jupiter and Sun, although
this is highly unrealistic. It depends on your local horizon how high up
you need Jupiter and on atmospheric conditions and the quality of your
telescope how far down you need the sun. Hjup > 8 and Hsun < -8 normally
work well. The entries for 10/12 and 10/15 at Greenwich and the ones for
10/12 and 10/26 here at WAS are questionable.
Have fun.
Herbert Prinz
Credits go to:
IMCCE for the times of satellite phenomena,
USNO for topocentric positions of Jupiter and Sun,
Herbert Prinz for all errors in the above.
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