August 2003 Sky from the Keeble Observatory
Mars! Mars! Mars!
We've been writing for two months about the fleet of probes on their way to the
red planet. We've told you that Mars will be at opposition (opposite the Sun in
the sky) in late August, a mere 34.6 million miles from Earth.
We're actually seeing a close convergence of two events . Mars will be at opposition
on the 28th, and also very close to perihelion at the same time that Earth is very
close to aphelion. (Perihelion is when a planet is closest to the Sun; aphelion
is when their separation is farthest. These events are at opposite ends of the long
axis through the elliptical orbit. Opposition means that the planet is on the opposite
side of the sky from the Sun's apparent position.) In this case, very close means
that opposition happens a mere two days before Mars reaches perihelion on 30 August.
The proximity with Earth's aphelion on 4 July is a little less tidy, but our orbit
is more nearly circular than Mars' orbit.
Closest approach will be just before 6:00 am EDT on the 27th. The last time we got
this close there were saber-toothed cats and mastodons in North America! That was
in August or September of 57,617 BCE, depending on whose calculations you believe.
Of course, the months hadn't been invented yet! The next opportunity won't take
quite as long . keep a sharp eye on 2287 August 29!
Unfortunately, viewing Mars from the vicinity of the Center of the Universe (Ashland!)
won't be ideal. At best, the planet will be about 37 degrees above the southern
horizon at about 1:30 am . from our vantage point at the Keeble Observatory, Mars
won't even clear the tree line until almost 11:00 pm. This relatively low altitude
will also exacerbate atmospheric interference from haze and sky glow. As we approach
the dates for opposition, we'll post on the Keeble homepage to let folks know if
we will be trying any observing.
Lunar phases for 2003 August: First Quarter on the 5th, at 3:29 am; Full on the
12th, at 12:49 am; Last Quarter on the 19th, at 8:49 am; New Moon on the 27th, at
Saturn emerges from behind the Sun and is visible in the predawn towards the east.
Mercury is low towards the northeast at sunset, and we've lost Jupiter and Venus
in the Sun's glare. Mars rises earlier each night - rising as the Sun sets on the
28th, visible through the night for the whole month.
Our overhead view at mid-month, roughly an hour after sunset, brings the bright
star Vega close to zenith. The constellation Hercules is at zenith, extending a
bit to the west, but this faint tetrahedron is not obvious, except on clear, moonless
nights. Bright red Antares, in Scorpio, is almost due south. The brightest star
in the constellation Bootes, Arcturus, is almost due west. To the northwest we see
the familiar big dipper of Ursa Major. Following the sweep of the handle towards
the west will lead you to Arcturus, and continuing the arc towards the southwest
will bring into view Spica, in the contellation Virgo. This is low in the sky, and
may not be visible through the horizon haze. Returning to Vega and turning towards
the east, you'll see the bright triangle formed by Vega, Deneb (in Cygnus) and Altair
(in Aquila). Cygnus (the Swan) marks both the plane of the Galaxy and the direction
in space towards which the entire solar system is moving as we orbit the center
of the Milky Way, which divides the sky roughly from south-southwest to north-northwest.
For your own monthly star chart, you can direct your web browser to
http://www.skymaps.com. You will find extensive descriptions of what's worth
looking for, and you can download and print a single copy for your personal use.