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Old 02-19-2009, 07:35 PM   #2
Dantheman62
Avalon Senior Member
 
Join Date: Sep 2008
Location: So. Cal. U.S.
Posts: 4,205
Default Re: Hopi Blue Star = Comet Lulin?

Here's some more info.......

On the night of Feb. 7, for instance, Lulin will rise above the east-southeast horizon around midnight and will appear at its highest in the sky toward the south at the break of dawn. But on the night of the 24th, when it will be passing nearest to Earth, Lulin will be visible all night, rising in the east at dusk, peaking high in the south shortly after midnight and setting in the west around sunrise.

Currently located in the constellation Libra, Comet Lulin will appear to move on a northwest trajectory, crossing over into Virgo on Feb. 11 and passing 3-degrees north of the 1st-magnitude star Spica in Virgo on Feb. 16 (for comparison, your clenched fist held at arm's length measures about 10-degrees in width).

On the night of Feb. 23, now virtually at its peak brightness, the comet will be sitting just 2-degrees south-southwest of the planet Saturn, which you can use as a benchmark to locate the comet. Moreover, around this time, Comet Lulin will be racing at more than 5-degrees per day -- that's roughly the equivalent of the distance between the stars Dubhe and Merak, the "Pointer Stars" of the Big Dipper; so even a few minutes of watching with a telescope should reveal the comet's slow shift relative to background field stars.

On Feb. 27, the fading comet will slip just 1-degree south of the 1st-magnitude star, Regulus in Leo. And come the night of March 5, Lulin -- by then probably between magnitudes 6 and 7 and no longer visible without binoculars or a telescope -- will pass to within 2-degrees of the famous Beehive Star Cluster in Cancer.

Look for an Antitail

Comets are visible because radiation from the sun releases gas and dust from the comet. That material then shines with reflected sunlight, creating a cloudy head, or coma, and sometimes one or two tails.

Even when it's at its very brightest, naked-eye observers probably see Comet Lulin as resembling only a dim, fuzzy star. In binoculars, or a small telescope the comet may resemble an apple on a stick; that is, the comet's diffuse head or coma should appear round and somewhat condensed toward its center, with perhaps a tinge of blue or green, while a narrow tail of gas extends out to the northwest.

In addition, telescopic observers should also look for a "spike" of light, pointing in a direction opposite to the tail. This strange effect, called an "antitail," is caused by a thin sheet of dust that is expelled by the comet but normally is visible for a brief interval when the Earth passes through the comet's orbital plane.

But because Earth will remain in the comet's orbital plane through February and on into March, there will be an ongoing chance of catching a glimpse of the antitail as well.

http://www.space.com/spacewatch/0902...met-lulin.html
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