SKYLIGHTS
Astronomy news for the week days starting Friday, August 6,
1999.
The next Skylights will be posted on August 15. It is a great week
for astronomy as the Moon moves through its waning crescent phase
early in the week heading toward new on the morning of Wednesday,
November 11 and its rendezvous with the Sun. Because of the tilt
of the lunar orbit, the new Moon usually passes above or below the
Sun, but this week it will cross directly in front to produce a
total solar eclipse. Unfortunately totality is nowhere visible in
North America. Instead, the eclipse path begins in the western
Atlantic and crosses Europe just north of Paris, across Stuttgart
and Munich, then passes through Austria, Hungary, Romania, Turkey,
Iran, and India. If skies are clear, however, northeasterners from
Pennsylvania through New York and into northeastern Canada can see
a partial eclipse at or near sunrise. Totality occurs because the
Moon, while new, is also close to perigee (when it is closest to
the Earth, on Saturday the 7th), as otherwise the lunar shadow
would not quite reach Earth.
For the rest of us there is the delightful annual Perseid meteor
shower, which peaks the mornings of Thursday the 12th (the night of
the 11th) and Friday the 13th. With no moonlight the view should
be good, but you need to have dark country skies to see the event
best. There you may see a meteor or so a minute, maybe more,
seeming to emanate from the constellation Perseus. The meteors
consist of small fluffy debris that has flaked from Comet Swift-
Tuttle. As we pass the comet's orbit, the debris rains down on the
Earth, heating and producing streaks in the atmosphere. Though the
meteors seem to come from Perseus (a perspective effect), the best
place to look is always overhead in early morning when we are on
the side of the Earth that sweeps the little particles up. Be sure
at the same time to admire Perseus, in the Milky Way to the east of
Cassiopeia.
All this activity overwhelms distant Uranus, which passes
opposition with the Sun on Saturday, the 7th. Now at its
brightest, the planet can just barely be seen with the naked eye
among the dim stars of the constellation Capricornus. Though
Uranus is hard to see, Mars, in the southwest at sundown, is not,
the red planet moving slowly east against the stars of Libra. The
morning sky holds more, bright Jupiter high to the south at dawn,
Saturn a bit to the east of it, and Mercury low to the east as the
morning sky brightens, the little planet reaching its greatest
elongation west of the Sun on Saturday the 14th.
