Photo(s) of the Week.. At left is an especially
lovely and wide "lunar corona," a diffraction ring around a
nearly-full moon caused by the mutual interference of light waves
as they pass through high clouds made of small water droplets or
ice crystals. (You see the same thing looking at a light through
fogged eyeglasses.) At right is a longer exposure that over-
exposes the Moon but reveals a rare second-order ring around the
first one. Both were easily visible with the naked eye. A third
ring was elusive.
Astronomy news for the two weeks starting Friday, June 3, 2016.
The next skylights will appear June 17.
With the Moon pretty much out of the way during the first half of
the fortnight, the night sky darkens, allowing the stars to shine
through. We begin appropriately with the beginning Moon, the new
Moon, which takes places on Saturday, June 4. With a good horizon,
by the evening of Sunday the 5th you should see the ultrathin waxing crescent in western twilight. By
the following night, the growing crescent should be obvious as the
Moon heads towards its first quarter
the night of Saturday the 11th shortly after moonset in North
America. That evening the Moon will fall to the east of bright Jupiter (while appearing
to the west of it the previoius night). The
Moon then fattens through its waxing
gibbous phase, not hitting full until
next week, on June 20. The night of Thursday the 16th, our
companion will shine northeast of Mars and
Saturn. The fortnight begins with the Moon at perigee (closest to the Earth). Our companion then
moves away from us until it hits apogee on Wednesday the 15th,
where it is around 11 percent farther than it was at perigee.
As presaged above, a glorious trio of planets awaits the most
casual of observers. Jupiter, to the southeast of Regulus in Leo, leads the parade. Riding down the western sky,
the giant planet does not set until around midnight. We then
switch our sight to the southeast, where in early evening we find
reddish Mars (almost as bright as Jupiter) and, following, dimmer
(though still quite bright) Saturn. To the south of the pair
shines the red supergiantAntares in Scorpius, the trio
crossing the sky and not setting in the southwest until dawn.
Inside Earth's orbit, Mercury is
barely visible in eastern morning twilight, passing greatest
western elongation (24 degrees west of the Sun) on Sunday the 5th,
while Venus is
completely invisible as it goes through superior conjunction with
the Sun
(on the other side of the Sun) the following day. It will become
visible in western twilight next autumn. To complete the planetary
act, Neptune, in
northern Aquarius near the border with Pisces (and visible in
binoculars to the east of Lambda
Aquarii), begins retrograde
motion on Tuesday the 14th.
Mars and Jupiter together are a guide to an amazing concentration
of hot massive stars in Scorpius (to the south of the planets), Lupus (farther south), and Centaurus (to the southwest). Here
we find loose associations and sub-
associations that have given us generations of supernovae and have
cleared the local interstellar region of much
of the usual gas and dust, leaving us within a "local bubble."
Well to the west of Scorpius, on the other side of Libra, slithers the tail of Hydra, the Water Serpent.
