Babe Among the Stars: Comet Lulin and Hubble's Swansong

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Galaxy Babe's column banner, showing a full moon and some little folk looking up at the sky

Mortal as I am, I know that I am born for a day. But when I follow at my pleasure the serried multitude of the stars in their circular course, my feet no longer touch the earth - Ptolemy

Breaking News - Comet Lulin

Hopefully you'll remember me mentioning Comet Holmes in late 2007, which was pretty spectacular and even changed the look of Perseus, as we know it, for a short time. Ancient cultures — the Chinese, in particular — thought comets were 'celestial ambassadors', and even today comets have a reputation for being Harbingers of Momentous Events. Another comet is heading our way  (but at the closest approach of 0.4AU [38 million miles] it will pass nowhere near the Earth, I'm pleased to report) and they are always worth looking out for.

This one is a brand new visitor to the inner Solar System: Comet Lulin (officially catalogued C/2007 N3), was discovered by 19-year-old meteorology student Quanzhi Ye of Sun Yat-sen University and named after the Lulin Observatory of the NCU, which is where the first images were obtained. Its coma (atmosphere) is 500,000km (311,000 miles) wide, that's triple the diameter of Jupiter! We now know that it has a tail and an antitail which hopefully will lead to more spectacular shots of this turquoise-coloured fleeting visitor.

From our perspective Comet Lulin will be right next to Saturn on Monday night, 23 Feb, begin your observations at 11pm and be prepared to skywatch until at least 3am. For lucky viewers with dark skies, Comet Lulin will look like a fuzzy ball, visible to the naked eye. Binoculars or a telescope will aid your chances of locating the comet, and maybe a tail or two. Unfortunately people living in cities and well-lit areas will probably need to find a dark sky viewing area. Saturn, in the constellation Leo in the south, is the brightest object in that part of the sky. Comet Lulin should be about 2° below and to the right of Saturn. If the weather is bad or you can't skywatch that night, here is a comet map with the dates and the comet's position in red against a constellation map. Happy comet ferreting, and good luck!

Comet Lulin is estimated to be travelling at 140,000 mph. If you're unlucky and don't catch a glimpse while it is coursing through our neck of the woods, it's always worth a peek at Astronomy Picture of the Day; as I write this there are already two images of Comet Lulin there, uploaded on 02 Feb 09 and 07 Feb 09. Comet Lulin is shaping up to be one of the astronomical events of 2009, although it will have to put on a grand performance to beat its compatriot Comet Holmes!

Hubble's Swansong

Some of the most breathtaking space images I've seen have been supplied by the Hubble Space Telescope. Now earmarked for retirement, the HST is scheduled for its last servicing this year. The people at HubbleSite are providing the general public with an opportunity to participate in the HST's final fling, as part of the celebrations during the IYA (International Year of Astronomy). What they'd like you to do is go look at the six images they have selected on their website and vote for which one you would like the Hubble to image.

For your consideration I have listed the options here, as well as adding some further information. There's no skill involved, just pick your personal favourite and click to vote. An added incentive is they are giving away 100 16"x20" photos of the winning astronomical object after it has been processed by the Hubble team. Voting closes on 1 March so you haven't got long, remember to fill in your email address in case you are one of the lucky winners of the draw, whom they will notify by 30 April.

The Candidates
  • NGC 40 is a planetary nebula in Cepheus. This is the best image we have of it so far: NGC 40. Hubble can do so much better!

  • NGC 4289 is an edge-on spiral galaxy in Virgo. It has another catalogue name, Tempel 1; indicating that it was discovered by Ernst Wilhelm Leberecht Tempel in the year 1877. He is the astronomer who co-discovered the comet Tempel-Tuttle (55P/Tempel-Tuttle) which is the periodic comet responsible for our annual Leonid meteor shower.

  • NGC 5172 is a classic spiral galaxy in Coma Berenices. There are billions of individual stars here, all gravitationally-bound. A star city in all its glory is a tempting thought.

  • NGC 6072 is a planetary nebula in Scorpius. Would a Hubble image of this elevate it to the iconic status currently enjoyed by the Crab Nebula and the Horsehead Nebula?

  • NGC 6634 is an emission nebula — a star-forming region in Sagittarius. A Hubble image of this expanse would possibly fire the imaginations of many generations of would-be astronomers for decades to come.

  • ARP 274  – ARP stands for Atlas of Peculiar Galaxies. ARP 274 is a pair1 of spiral galaxies just beginning to merge. At the moment the couple are at the holding hands stage, displaying the first flush of attraction. It will be a while yet before it's a full-blown cosmic trainwreck, when they will literally tear each other apart before merging into one huge galaxy, a process which takes many millions of years.

So as not to influence your vote I won't be letting on what I finally plumped for right now, but I am interested in what you think I did vote for. I'll be happy to hear what you voted for too, so do let me know if you take part. I'll confess what I voted for in my next column, and also publish the result of the HubbleSite viewers' choice as soon as I know it.

  • Chat about your celestial observances at the H2G2 Astronomy Society. Comment on anything in this edition of Babe Among the Stars by starting a new conversation below.

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1Some websites say ARP 274 could be three merging galaxies!

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