Astronomy news for the two weeks starting Friday, July 29,
2016.
The next skylights will appear August 12.
We begin with a wisp of a waning crescent
Moon, which terminates at new Moon on Tuesday, August 2. Your
last view of it will be in eastern twilight the morning of Monday
the 1st. We then turn in the other direction to see the waxing crescent, which will appear the
twilit evening of Thursday the 4th immediately to the left of Mercury, with
Venus a bit
farther down and much farther to the right, the bright planet hard
to see. The following evening, that of Wednesday the 5th, will be
better, with the Moon just to the west of Jupiter. The
Moon will occult, or cover, the planet after the two have set.
Look then the next evening to see the Moon well up and to the left
of the giant planet. After passing first
quarter on Wednesday the 10th, it enters the waxing
gibbous phase as it heads towards full on August 18. The evening of Thursday
the 11th, the Moon will appear directly above Mars, while to
the right
Saturn will be just above the star Antares, the four making a nifty
quadrangle. The Moon passes apogee, where
it is farthest from Earth, on Tuesday the 9th, less than a day
before first quarter.
After giving us a lovely show over the past few months, Jupiter is
disappearing from the nighttime sky, now setting before evening
twilight draws to a close. It'll be back in the east in October.
And as augured above, Mercury is making a bit of an appearance in
western twilight. So is Venus.
Climbing only slowly from night to night, Venus does not get into
a dark sky until mid-October. But we still have Mars and Venus.
With Mars moving to the east against the stellar background, and
Saturn (just to the east and north of Mars) very slowly still
moving retrograde (to the west), the two are on course to
pass each other. But before then the chase will be on, as Saturn
ceases retrograde about as our fortnight ends,and slowly reverses
to move easterly in direct mode. But it's no match for speedy
Mars, which will catch it on August 25. All this action plays out
against the bright stars of Scorpius, in particular Antares, which
is almost due south of the ringed planet. Mars is to the west
of bright second magnitude Delta
Scorpii (the middle star in the trio that makes the Scorpion's
head) and will pass just south of it on Tuesday the 9th. Not to be
completely outdone, Uranus ceases
retrograde on Friday, July 29.
The best, however, is yet to come. August is the time for the Perseid meteor shower, which
appears to emanate from the constellationPerseus. While lasting over several nights, the meteor
display (from the debris of Comet
Swift-Tuttle, which last came by in 1992) peaks the morning of
Friday the 12th with the Moon well out of the way. The shower is
predicted to be better than the normal average of a meteor per
minute in a dark sky.
It's a good time to look at the Dippers. In early evening the Big Dipper of Ursa Major falls into the northwest while the Little
Dipper of Ursa Minor stands on its
handle, Kochab (Beta Ursae Minoris) above Polaris. Between the
Dippers wags the tail of Draco
the Dragon, while halfway between Kochab and the Big Dipper's end find
Thuban, which (as a result of precession, the 26,000-year wobble
of the Earth's axis) was the pole star during the time of ancient
Egypt.
