January 2008 Sky from the Keeble Observatory
What would you do if you had one last chance to renovate and refurbish your favorite car, knowing that you would only be able to drive it for another 20,000 miles?
When it was launched in April 1990, the Hubble Space Telescope was hailed as the greatest instrumental advance in astronomy since Galileo first looked up through his telescope. Excitement turned quickly to dismay, as preliminary tests revealed that its 2.6 meter primary mirror was flawed. Ground with high precision to the wrong shape, (the edge of the mirror was too high relative to its center by approximately the thickness of a human hair) Hubble began to look like a technological embarrassment. The cause of the error was a testing “jig” which had been assembled with one component out of place. Knowing that, and actually having the device available, it became possible to design corrective optics, which were installed by shuttle astronauts in 1993.
Since then, the telescope has returned spectacular images and science, more than living up to its initial promise. Three subsequent service missions have replaced solar arrays, gyroscopes, and most of the scientific instruments, making Hubble even more powerful, and earning it a nick-name: the People’s Telescope.
Designed to be serviced and upgraded from the Shuttle, its fate seemed sealed when NASA administrator Sean O’Keefe decided after the loss of the shuttle Columbia in 2003, that further missions to Hubble were too risky, and that HST would be left to die in orbit and burn up in Earth’s atmosphere on reentry. Two years later Mr. O’Keefe’s successor, Michael Griffin revisited the question and convened an expert panel to fully evaluate risks and benefits. A little over a year ago, he approved a final mission to refurbish the telescope before the shuttle fleet is supposed to be retired in 2010. That mission is now scheduled for next August, when Atlantis will pay its last visit.
Next month, we’ll discuss what changes will be made to the People’s Telescope. It will be getting more than just new tires!
Lunar phases for January: New Moon on the 8th, at 6:37 am; First Quarter on the 15th, at 2:46 pm; Full Moon on the 22nd, at 8:35 am. Last Quarter on the 30th, at 12:03 am.
Early morning sky watchers will find Jupiter very low on the southeast horizon, rising less than an hour before sunrise at the beginning of the month. You’ll likely only be able to see it if you have a clear horizon and no haze. By the end of January, it’s lead on sunrise increases to about two hours, but the angle of the ecliptic is fairly shallow so it still only climbs to about 20 degrees before the sun clears the horizon. Venus is still the brightest predawn object, beginning the month about 26 degrees above the southeast horizon at sunrise. It will draw closer to the sun as the month advances, drawing within a degree of Jupiter by the 31st. Saturn is west-southwest at dawn, 40 degrees above the horizon, above and to the left of Regulus, in the constellation Leo. It will end the month setting earlier, about 15 degrees off the horizon at sunrise.
Mars is visible most of the night, beginning the month low to the east-northeast at sunset. By the end of January, Mars will rise about three hours before sunset, and will emerge from twilight about 45 degrees above the horizon. Mercury begins the month low to the west at sunset, reaching maximum eastern elongation and setting about an hour after sunset on the 22nd.
Our overhead view at mid-month, about three hours after sunset finds the Milky Way dividing the sky, running from northeast to southwest. It’s hard to see with street lights and other light pollution, but getting away from the city will allow you to enjoy this spectacular sight. The brightest star near zenith is Mirfak, in the constellation Perseus.
Following the Milky Way towards the southeast brings our view past Capella and Elnath, in Auriga. That’s Mars just below Elnath. (Or, shall we say that Elnath is the star just above Mars, since the red planet is easier to identify?) Then we turn our attention to what is, for me, the most interesting part of the sky. Orion, the familiar winter constellation is clearly visible. That bright red star on his “shoulder” is Betelgeuse – a red supergiant. This star is about 20 times the mass of our Sun, and if it were placed where the Sun is, we’d be inside it! Its radius is roughly the same as the orbit of Mars. It is thought to be near the end of its lifetime, and expected to end as a Type II supernova – though that even is not expected for millions of years.
Below the familiar “belt” we find the Orion Nebula. This is the closest star-forming region to the Sun, a stellar “nursery” a mere 1500 light years distant. Binoculars or a small telescope will reveal the bright Trapezium Cluster illuminating the nebula. These stars are less than a million years old.
Below Orion we find the brightest star in the night sky, Sirius. This star is actually a binary, but its companion is a tiny, dim white dwarf which can only be resolved with a large telescope. Above Orion we find the bright star Aldebaran, marking the eye of the bull in the constellation Taurus. We also see the nearby open cluster, the Pleiades. These are young stars, though not as young as the Trapezium cluster – perhaps ten million years old.
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.
Copyright 2008George Spagna