SEPTEMBER  2004

SEPTEMBER STAR MAP | STARWATCH INDEX | MOON PHASE CALENDAR

Print Large Sky Charts For 10 p.m. EDT:   NORTH | EAST | SOUTH | WEST | ZENITH

Venus passes Saturn:   Venus is the brightest object in this 5:15 a.m. digital photo taken on September 1 from Coopersburg, PA. Saturn is immediately above and to the left of Venus. The other stars in the photograph are part of winter constellations that will be dominating the sky in February 2005. Gary A. Becker photo…

419    SEPTEMBER 5, 2004:   Milky Way Splendor

In early September for mid-latitude observers, our Milky Way Galaxy straddles the entire sky, passing overhead for the first several hours after darkness. For a successful observation, it is paramount that you get away from city lights and view under an atmosphere free of haze. By 10 p.m. the Milky Way rises from the northeastern horizon and sashays upward through the constellations of Perseus and Cassiopeia, arcing high overhead through the Great Summer Triangle, then downward through Sagittarius, disappearing along the southwestern horizon. As the eye tracks the length of this star-drenched pathway from NE to SW, the brightness of the galaxy grows. You are looking ever closer to the Milky Way’s center in Sagittarius. Photos and a map can be found at Web StarWatch at the URL below. A friend of mine, Great Bear Cornucopia, night sky interpreter at Chaco Culture National Historical Park near Nageezi, New Mexico, loves to tell the story of the city slicker, who excitedly came to him one morning, with the story of an unidentified astronomical sighting. Expecting the usual UFO or alien tripe, G. B. had a pleasant surprise awaiting him. Roused by the call of nature in the middle of the night, the camper had crawled from her tent to behold a powdery path of gossamer starlight stretching across the heavens. Happily, G. B. was able to inform her that she had made her own personal discovery of the Milky Way. If you want to be inspired or spiritually awakened, stand under a dark sky with the soft powdery glow of the summer Milky Way overhead. It is often my personal catharsis for the stresses of an urban existence. I’ll continue my discussion of our home galaxy next week.

Our home galaxy, the Milky Way, can be seen under dark skies by 10 p.m. in early September. A good friend of mine, G. B. Cornucopia, night sky interpreter at Chaco Culture National Historical Park near Nageezi, New Mexico, loves to tell the story of the camper, who one morning came to him excitedly with the story of an unidentified astronomical sighting. Roused by her bladder in the middle of the night, she crawled from her tent to behold a powdery path of shimmering starlight arched across the heavens. Great Bear, yes, the name is real, was able to happily inform her that she had made her own personal discovery of the Milky Way.

These three images of the Milky Way show our galaxy in the NE (left), directly overhead (center), and in the SW (right) as it appears in early September. Each digital image was 8 minutes in length and manipulated in a similar fashion. Moving from left to right, the eye scans ever closer to the center of the galaxy. Photgraphy by Gary A. Becker, Star Hill Inn, Sapello, New Mexico...

420    SEPTEMBER 12, 2004:   Milky Way Now

Now is the best time to see the Milky Way, home to our solar system and another 400-billion stars. It straddles the sky from NE to SW, but you’ll need haze-free, rural skies to make the most of its cottony texture. Viewed from above our galaxy has a spiral-shaped form, similar to stirring white paint into a bucket of black. Seen on edge the Milky Way is flattened with a bulbous center. Our solar system is positioned about 28,000 light-years from the galactic center, but just five light-years above the galactic plane, about halfway to the visible edge. Even though we reside near the galactic plane, astronomers are aware of at least a half dozen spiral arms that encircle the galaxy. View NE around 10 p.m. towards Perseus and the sideways “W” of rising Cassiopeia, and you will be looking away from the bulge towards the closest exterior spiral to us called the Perseus arm. Turn your head to the SW towards setting Sagittarius and you’re looking at the Sagittarius arm, the closest inner spiral to us. So which arm do we call home? Neither… We believe that we’re on a little dinky “Third World” star bridge connecting Perseus to Sagittarius called the Orion arm. You’ll have to wait until winter before Orion the Hunter, the pattern that lies towards the Orion arm, can be seen after nightfall. Understanding the structure of the Milky Way from Earth is similar to mapping NYC from the vantage point of a single penthouse suite on the Upper West Side. It would be obvious that the hub of the city lay to the south, but differentiating the individual boroughs from line of sight observations made from one rooftop would prove trickier. It’s a similar challenge faced by astronomers trying to decipher the structure of the Milky Way from our penthouse called Earth.

421    SEPTEMBER 19, 2004:   All in the Mind of God

If you have ever looked at a roadmap or watched the land passing under the wings of a moving plane, it is obvious that we humans like to cluster. Whether it is in villages, small towns, or the largest urban centers, the need to group seems to be part of the human experience. It is likewise with our universe. Moons revolve around planets, planets around stars, and stars orbit great and small galactic systems. Over half of the luminaries in our Milky Way are double or multiple systems. Stars get born from large nebulas of gas and dust to form open clusters, many dissolving into the general population of the galaxy over time. Orbiting around the galaxy’s hub is a halo of huge old clusters called globulars, formed about the same time that our galaxy came into being. We currently believe that the Milky Way has at least nine galaxies orbiting it, two easily visible from the southern hemisphere and the rest, dimmer and scattered around the sky. The Milky Way is the most massive galaxy of a small cluster of galaxies called the Local Group that currently contains 45 members. Our own Local Group is part of an even larger aggregate of thousands of galaxies called the Local Supercluster. And on and on it goes until you have the universe itself. If you’re wondering what the universe would appear like on the largest scale, then think of an airy sponge. You would notice lots of vacuous space surrounded by tendrils and globs of spongy material. The sponge’s texture would represent the galactic clusters and superclusters stretched across the fabric of space and time. Beyond our universe many theorists believe a myriad of other universes may coexist. In the end, perhaps all of this grandeur forms but a small convolution within the infinite mind of God.

422    SEPTEMBER 26, 2004:   Where Have All the Planets Gone?

What a bonanza of planetary happenings were occurring last year and this past spring! Bright red Mars was still making headlines, and enthusiasts were queuing up behind telescopes to catch a glimpse of the Red World. Then as temperatures chilled and Mars faded, Venus debuted, followed in turn by Saturn and Jupiter. At one point in late March, Mercury snuck into the scene, and all five classical planets were strung across the sky like a loose strand of glimmering pearls. The Allentown School District Planetarium’s StarWatch Team entertained well over a thousand planet seekers during that period, including those who viewed the rare Venus transit on June 8th. So what has happened since then? The heavens are in a continuous state of flux as the planets orbit the sun, and as our own observing platform Earth orbits Sol as well. As we circle, the sun changes its position among the stars, a reflection of our own orbital motion. Eventually, the sun overtakes the planets that we were watching. During this week Mercury, Mars, and Jupiter will form a very tight little grouping on the eastern horizon about 30 minutes before sunrise. No, you won’t be able to see it, but as the months roll on, both Jupiter and Mars will seem to pull away from the sun to become easily visible in the morning sky. There are two well-positioned morning planets that can be seen right now. That truly magnificent luminary in the east will be Venus. On October 3 it will be less than one third of a degree from Regulus, the brightest star of Leo the Lion. Above Venus will be Saturn. It is currently in line with Castor and Pollux, the brightest stars of the Gemini Twins. Make sure you are outside by 6:00 a.m. at the very latest. An online map is included with this StarWatch edition.