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Planets and Perseids

© Gregg Pasterick

This month's highlights are, as usual for August, planets and Perseids. The planets in question are Venus and Jupiter, which pick up the slack from the gathering of Venus, Mercury, and Saturn earlier in the summer. The Perseids are ... well, the Perseids.

The two bright planetary lights among the stars spend the month approaching each other. Actually, it's Jupiter doing the approaching. Venus remains pretty much stationary throughout the month. That is, it seems to stay in the same spot all month; the starry sky around it, of course, rotates behind it a little each night. Jupiter, it's own travels among the constellations much less pronounced than those of Venus, gets kind of dragged along with the stars. Thus, they are about 30 degrees apart at the beginning of the month, and only 1 1/2 degrees apart at the end. Their closest approach (appulse) is on the first of September.

But Jupiter's travels among the stars are observable thanks to magnitude 1.0 Spica in Virgo. As if dragged along in the wake of the giant planet, the bright star closes the distance between it and Jupiter during August; it is 11 degrees away on the first, and just 6 degrees away from Jupiter and Venus on the 31st.

But Spica's not really stalking Jupiter; it's Jupiter which is moving against the flow of the stars. If Jupiter were rooted in place, like the stars, it would have passed Venus by the end of the month.

Mars brightens to magnitude -1.0 in August, rising before 11:00 pm local time by the end of the month. It has, by this time, moved to within about 15 degrees of the Pleiades, in the star-rich piece of sky full of bright, colorful stars and ancient designs.

Saturn and Mercury are pre-dawn planets this month, Saturn climbing out of the twilight glare to rise about three hours before dawn by the end of August, while Mercury rises 5 1/2 degrees from the ringed planet on the 18th. It reaches its greatest elongation west on the 23rd, when it is 18.4 degrees from the sun.

The Perseid meteor shower, which has been active for about three weeks by the beginning of August, peaks on the 12th, a week before the Full Moon. The fat waxing Moon will set in time for plenty of pre-dawn observations, which is the best time to catch the most Perseids, anyway, as the radiant is gaining altitude. (In my many years of experience, Perseid rates always increased noticeably after 2:00 am local time.)

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