Sky At Totality
The total phase of an eclipse is accompanied by the onset of a rapidly
darkening sky whose appearance resembles evening twilight about 30 or 40
minutes after sunset. The effect presents an excellent opportunity to view
planets and bright stars in the daytime sky. Aside from the sheer novelty of
it, such observations are useful in gauging the apparent sky brightness and
transparency during totality. The Sun is in Virgo and a number of planets and
bright stars will be above the horizon for observers within the umbral path.
Figure 11 depicts the appearance of the sky during totality as seen from the
center line at 3:30 UT, which corresponds to the western coast of Myanmar.
Venus is the brightest planet and can actually be observed in broad daylight
provided that the sky is cloud free and of high transparency (i.e. - no dust or
particulates). During the 1995 eclipse, Venus is located 17 deg. east of the
Sun, having recently passed through superior conjunction in mid-August. Look
for the planet during the partial phases by first covering the crescent Sun
with an extended hand. During totality, it will be virtually impossible to
miss Venus since it shines at a magnitude of mv=-3.3. Although two magnitudes
fainter, Jupiter will also be well placed 42 deg. east of the Sun and shining at
mv=-1.4. Under good conditions, it may be possible to spot Jupiter 5 to 10
minutes before totality. Since this is a morning eclipse for observers along
the Asian path, Jupiter will be low in the southeastern sky and will be below
the horizon during totality from Iran through India. Only four days past
greatest western elongation, Mercury is 18 deg. west of the Sun at mv=-0.3 and
should also be an easy target provided skies are clear. The most difficult of
the naked eye planets will be Mars (mv=+1.3), appearing 32 deg. east of the Sun
between Venus and Jupiter. Saturn is near opposition 138 deg. east of the Sun
and will be below the horizon for all observers. Among the brighter stars
visible during totality, Spica (mv=+0.7) is located 7 deg. west of the Sun.
Other stars to look for include Regulus (mv=+1.35), Arcturus (mv=-0.04) Capella
(mv=+0.08) and Procyon (mv=+0.38). East of India, watch for Acrux (mv=+1.33),
Gacrux (mv=+1.63v), Alpha and Beta Centauri (mv=-0.01 & mv=+0.6v) all low
in the south while Antares (mv=+0.9v) stands low in the east 7 deg. from
Jupiter. Sirius (mv=-1.46) may be seen setting in the southwestern sky for
observers along the Iran-India segment of the path.
The following ephemeris [using Bretagnon and Simon, 1986] gives the positions
of the naked eye planets during the eclipse. Delta is the distance of
the planet from Earth (A.U.'s), V is the apparent visual magnitude of
the planet, and Elong gives the solar elongation or angle between the
Sun and planet. Note that Saturn is near opposition and will be below the
horizon for all observers during the eclipse.
Planetary Ephemeris: 1995 Oct 24 5:00 UT Equinox = Mean Date
Planet RA Dec Delta V Size Phase Elong
h m s deg ' " " deg
Sun 13 52 50 -11-34-47 0.99476 -26.7 1929.4 - -
Mercury 12 50 26 -3 -9-41 1.07410 -0.6 6.3 0.69 17.6W
Venus 14 59 26 -16-50-37 1.61647 -3.3 10.3 0.96 17.0E
Mars 16 0 43 -21-18-40 2.21358 1.6 4.2 0.97 32.1E
Jupiter 16 52 51 -22-10-18 5.96082 -1.4 33.0 1.00 44.2E
Saturn 23 22 2 -6-36-26 8.83178 0.1 18.7 1.00 138.3E
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