SKYLIGHTS
Astronomy news for the period Monday, May 17, through Thursday,
June 3, 1999.
This Skylights will cover the period through Thursday, June 3.
Skylights will resume weekly on Friday, June 4. We begin with the
Moon just past new, waxing through first quarter the night of
Friday, May 21st, at about moonset in North America, then growing
to full the night of Saturday, May 29, the phase reached near
midnight with the Moon low in the southern sky north of the red
supergiant Antares in Scorpius. The Moon passes apogee, its
farthest point from the Earth, the night before. The night of
Monday, the 17th, the thin crescent (the nighttime side glowing
with Earthlight) will be below brilliant Venus, the next night,
Tuesday, the 18th, it will be seen to the left. The Moon's "big
hit," however, takes place near the quarter the night of Friday,
the 21st, when it passes over, or occults, the bright star Regulus
in Leo, the event visible throughout North America. The times
differ by over an hour from one coast to the other. For the
central United States, disappearance takes place behind the dark
leading lunar edge about 11:10 PM daylight time, reappearance just
after midnight, about 12:10 AM. Binoculars will help make it a
fine show, the disappearance of the star startlingly abrupt,
showing how terribly small the angular sizes of the stars really
are. The night of Tuesday, the 25th, the Moon will appear above
reddish Mars and the bright star Spica, and once again, as in the
last phase cycle, it will occult Uranus and Neptune (respectively
on June 3 and 4), though neither event will be visible in the
western hemisphere.
The planets are "busy" during this period. On Friday, the 21st,
Jupiter (visible in eastern dawn) passes a milestone, perihelion,
the closest point to the Sun on its 12-year orbit, at a distance of
4.950 astronomical units, not that it makes much difference to the
naked eye, as Jupiter's orbit is not far from a circle. Uranus
begins its westerly retrograde motion the same evening. Then two
"invisible" planets get into the act, as Mercury goes through
superior conjunction in back of the Sun on Tuesday, the 25th, and
Pluto passes solar opposition against the stars of Ophiuchus (north
of the ecliptic plane) on Sunday, the 30th. Not to be left behind,
brilliant Venus will make a close pass to the bright stars of
Gemini, appearing only four degrees south of Pollux, the same
night.
As the time of solar passage across the summer solstice approaches,
the summer stars are beginning to make their appearances. Look for
bright Vega and Deneb climbing the northeastern sky, Scorpius and
Sagittarius crossing to the south after midnight, and before the
Moon brightens too much, for the Milky Way that streams between and
among them all.
