This 'LINEAR' C/2012 X1 was discovered after C/2012 S1 - i.e., ISON. 'S' vs. 'X'. This 'LINEAR' (and there are a lot of comets discovered by LINEAR) is still in the asteroid belt. It will not make perihelion till February 21, 2014. So it is trailing ISON by 3 months.

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