[BAA 00384] Comet Lulin

[Rick]

BAA electronic bulletin No. 00384 -- (c) 2009 British Astronomical Association http://www.britastro.org/

Comet 2007 N3 (Lulin) is now becoming visible in the evening sky, and reaches opposition on the 26th.  If the clouds part, it should be visible to the naked eye at around 5th magnitude, and through a telescope will show a rather unusual tail.  The comet has a retrograde orbit that is inclined at 178 degrees, which means that it moves nearly parallel to the ecliptic.  The gas tail will barely be visible as it will be pointing directly away from us, however the dust tail is a broad fan lying in the plane of the comet's orbit, so both a tail and anti-tail should be visible.  The geometry also means that the comet's brightness will be enhanced around the time of opposition due to the small angle between the Sun, comet and the Earth.  Images show the comet has a green coma, due to emission of light from the Swann bands of carbon, and from cyanogen.  Those with sensitive colour vision may see the colour through a telescope, but others will only see a white glow.

Now is the best time to observe the comet as the waxing moon will start to interfere with observations after the end of the month.  Currently in Leo, it is accelerating in daily motion as it approaches opposition.  After opposition it will fade quickly and by the time the moon is out of the way in mid March the comet will have faded by two magnitudes.  To compensate however, it will by then be high in the sky in Gemini, so much easier to see, even in light polluted areas.

This relatively bright comet gives beginners a chance to practice their techniques.  Visual observers can attempt magnitude estimates or drawings and imagers will only need short exposures to record the comet.  Guidance on making observations is given in the Section guide on observing comets, which is available for purchase from the BAA Office or on-line.

For the latest information about this and other comets, and some guidance on making observations, see the Section web page at http://www.ast.cam.ac.uk/~jds. You can also download the latest issue of the Section newsletter, which contains snippets of news, a review of the 2008 comets and an update to thepredictions for 2009 which appeared in the December Journal.

Jonathan Shanklin
Director, Comet Section

[Mike]

If you want to get some images of Comet Lulin then now is the time to do it. Over the next few weeks it will start to get a lot dimmer going down to nearly Mag 10 by the end of March.

Once it fades away the next chance you will have to see it will be in 49,435,956 years.