[AZ-Observing] Re: Robotic Lulin Shot last night

Steve Coe wrote: 

>will it [the anti-tail] not be directly aimed at our position and so also be 
>overwhelmed by the coma?

Steve,

"Anti-tail" is sort of a misnomer, since it's only an illusion that it points 
toward the sun.  I liken the anti-tail to the Zodiacal Light, as it is just 
scattered light from the tube of dust that the comet leaves behind.  So it 
points at the source of illumination.  It can be seen best when we are in the 
plane of that dust.  We have been in that plane for the last couple months 
because the comet has an inclination to the ecliptic of just over 1 degree.

At opposition, we should still see the anti-tail quite well, just as you see 
the Gegenschein 180 degrees away from the sun.  In fact, we should have the 
best view of the anti-tail, since the comet is nearly at its closest at 
opposition -- another oddity of this particular comet's orbit.  We will have a 
nice, broadside view of the comet's debris stream.

What I am curious about is the post-opposition view.  After opposition, the 
tail will flip over so it is pointing toward the east.  Will we see a comet 
with an anti-tail that points in the same direction as the tail?


> Can someone post the exact date and time of opposition?  I have looked for
> it but can't find it so far.

A daily ephemeris is at the IAU site.  Looking down the column titled 
"elongation", it reaches 178 degrees on the 26th.  It should be a very 
interesting sight on that date and afterward.

http://www.cfa.harvard.edu/iau/Ephemerides/Comets/2007N3_1.html

Tom
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