Photo of the Week. A fine circumhorizontal arc, caused by
sunlight refracting through ice crystals, courses across the sky
south of the Sun.
Astronomy news for the week starting Friday, August 15, 2008.
We begin the week with the Moon near the end
of its waxing gibbous phase as it approaches
full on Saturday the 16th. With the Sun descending the ecliptic from the Summer Solstice, our full Moons are
now riding upward from the Winter
Solstice, this one -- the "Green Corn Moon," the "Grain Moon" -
- lies between classical Capricornus and Aquarius just to the northeast of Neptune, which
passes opposition to the Sun as our week begins, on Friday the
15th. Having just had an eclipse of the
Sun on August 1, this full Moon will be
eclipsed, though just partially and seen in Europe and Asia,
the event not visible in North America. The remainder of the week
then sees our companion in the waning
gibbous phase. On Monday the 18th, it passes a few degrees
south of Uranus.
Some nice planetary action takes place nearly invisibly in western
twilight, as Saturn, Venus, and Mercury gather
together. On Friday the 22nd, Mercury and Venus pass conjunction
just 1.2 degrees apart, the event unfortunately not visible without
special equipment. At least we know it is happening.
So once again, for planetary viewing we turn to lonely Jupiter, which
now dominates the southern sky at the end of twilight, the giant
planet now crossing the meridian due
south (for those of us in the northern hemisphere) around 10 PM.
Setting ever earlier, Jupiter now goes down around 3 AM, leaving us
planet-less but for Uranus and Neptune, Uranus transiting just as
Mid-August in mid-evening finds the Scorpius-Sagittarius
pair (Sagittarius to the east, Scorpius to the west) crossing the
meridian to the far south. Due north of Sagittarius, white Vega shines nearly overhead in Lyra, while Arcturus sparkles orange-ly to the
west. Sagittarius is now easily located by looking down and a bit
to the right of Jupiter, though a bright Moon will blot much of it
out. Atop Scorpius, once the Moon is out of the way, look upward
to Ophiuchus (the Serpent
Bearer), then to Hercules, then to
the head of Draco, the Dragon.