FEBRUARY  2005

FEBRUARY STAR MAP | STARWATCH INDEX | MOON PHASE CALENDAR

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442    FEBRUARY 6, 2005:   Comet Machholz: Better Late Than Never

This week’s commentary reminds me of Howard Hughes, the notorious billionaire’s Air West that he assumed control over in 1970. A friend of mine dubbed it “Hughes Air Worst,” and often said jokingly that their corporate motto was, “Better late than never!” In a way this article is a reflection of that motto because Comet Machholz has been visible in the sky as a binocular target for over a month. In the excitement of reporting about my astronomical travels to New Mexico, I forgot to make mention of it. In retrospect, had I touted Machholz in a timelier fashion, the weather would have been cloudy. But I’m not going to use that as an excuse either. Just give me a demerit. Here is the scoop. Most of the 25-40 comets harvested annually go unnoticed by even the professionals. Once every year or so, a comet becomes bright enough to be seen with binoculars from suburban and rural locales. That is the category of Colfax, California amateur, Donald Machholz’s tenth comet which was discovered last August 27 after 1457 hours of comet sweeping with his 8-inch reflecting telescope. What gives Comet Machholz the edge is that it is positioned in the north circumpolar region of the sky where it is visible all night. Go to the current on-line edition of StarWatch at the URL below for a 9 p.m. map that will show Comet Machholz’s location for the next several weeks. Use the pointer stars of the Big Dipper and the North Star to reference how you will move your binoculars to find the small fuzz ball-looking object. Keep in mind that at minimum, you will need a very transparent, moonless, suburban sky to see Comet Machholz. View with averted vision. You’ll see more if you don’t look directly at it. The rod cells in the eye’s periphery are more sensitive to light.

443    FEBRUARY 13, 2005:   Sirius: Brightest Star of the Night

It happened on a website a long, long time ago. After untold thousands of planetarium programs and kids consistently telling me that the brightest star of the night was the North Star, I was perplexed. So I posed the same query to a national audience. “Name the brightest star of the nighttime sky.” The answers I provided were, of course, the North Star, and such other bright, recognizable luminaries as Betelgeuse and Rigel of Orion the hunter, Capella of Auriga the Charioteer, and the correct answer Sirius, the Dog Star of Canis Major. Since the question had to be submitted months ahead of its posting date, I picked my birthday, June 10th, for its unveiling in hopes that I would remember to check back. On that day, there were just over 2000 respondents. I remember specifically that 51 percent chose the North Star as the brightest star of the night. About ten percent of the voters touted Sirius, pretty much as I expected. This week, you can break the chains of this misconception. If you go outside at 9 p.m. and face due south, Sirius will be shining about one third of the distance up from the horizon. Because of its low altitude and brightness, Sirius often twinkles wildly from even small amounts of atmospheric turbulence. It may flash reds and blues as its light is refracted and dispersed on its way towards your eyes. Now do an about-face, so that you are looking north, but gaze just a little higher in the sky. From the city, suburbs, or a rural locale, you’ll notice the much fainter North Star, the luminary about which the sky turns. The Big Dipper will be to your right, cup up, handle down with the two top stars of its bowl pointing at the North Star. “Siriusly,” take a few minutes to put the North Star in its pivotal place, just the 47th brightest star of the night.

Sirius is the brightest. Most people confuse the North Star’s stationary position with its brightness and call it the brightest luminary of the night. The North Star ranks 47th brightest, 48th if the sun is included. It would take the brightness of 23 North Stars to equal one Sirius.

444    FEBRUARY 20, 2005:   Egypt's Confusing Calendar

It is a fact that the Egyptian astronomer Sosigenes of Alexandria introduced the solar calendar to Julius Caesar and the leap year to correct for the inability of the Earth to complete one orbit around the sun in a whole number of days. The Earth requires 365.24 days for one revolution, but since we give it only 365 days to complete this task, it falls a quarter day short each year. At the end of four years, an extra day is added to the calendar to rectify this inadequacy. Sosigenes had proven his worth to the Romans, but Egyptian calendars were rife with confusion unless you were the priest maintaining its accuracy. The beat of Egypt’s solar calendar was the rising of Sirius, the brightest star of the night, visible this week low in the south at 8:30 p.m. In antiquity, the year began when Sirius was first spotted ascending in the ESE before the brightening dawn of a new morning washed it away. This happened shortly after the summer solstice or high sun, and was followed by the seasonal flooding of the Nile River. Watching repeated helical risings of Sirius, while maintaining a day count, established the solar year. The Egyptian calendar had 12 months, each consisting of 30 days, a throwback to even earlier times when the phase period of the moon, 29.54 days, established the basic calendar. There were five additional intercalary days added to the 360 day year, but the extra quarter day that eventually accumulated into a leap year and which was an integral part of the Julian and the more modern Gregorian calendars was missing. Ironically, Egyptian astronomers were fully aware of its existence but did nothing about it. Festival days slowly cycled backwards through the seasons over a period of 1461 years, creating what the Greeks called the Sothic (Sirius) period.

445    FEBRUARY 27, 2005:   Salute to Bryce!

For the last several weeks I have been detailing the itinerary for a SW Field Experience, a joint effort between the Allentown School District Planetarium and Dieruff High School’s Environmental Academy. Accompanying me will be most of Dieruff’s StarWatch team of student astronomy enthusiasts. New and truly wondrous experiences await them. For three nights we will be observing under a star-drenched firmament at Chaco Culture near Nageezi, New Mexico, the only national park to possess a working observatory and a mission statement which supports the conservation of the night sky. Then it is northward to Moab, Utah where we will spend four days studying the ecology of the tumbling Colorado through remote Cataract Canyon in Canyonlands National Park. I cannot wait to be sleeping by the river, fire dimly glowing, moonlight cascading across precipitous, slickrock walls, while brilliant stars pierce a deep lapis blue sky. Notwithstanding the canyon and the Colorado, a transparent, dark night sky is the magic of dreams that now can only be realized through travel. Along with Chaco Culture, Utah’s Bryce Canyon NP, east of Cedar City, has aggressively begun to target the dark night sky as a natural resource. Friend, Angie Richman, an astronomy graduate from the University of NM in Albuquerque cut her interpretive teeth at Chaco and has helped to launch a similar program at Bryce. Within one year Bryce’s night sky initiative has become its most popular magnet, attracting 300 participants per evening. Just like Chaco, tourists are exploring the canyon by day and gaping wide-eyed into the star-splashed heavens at night. It is a mandate that other parks need earnestly to consider and incorporate into their mission statements. Salute to Bryce!