While Comet ISON is brightening rapidly, Comet Lovejoy (C/2013 R1) is far more impressive right now in the pre-dawn sky.
Reports indicate that the brightness of Comet ISON (C/2012 S1) has surged recently, so I went out this morning to check it out for myself. And tipped off by Greg Crinklaw's Comet Chasing site, I also looked for the three other bright comets that are currently up in the morning sky.
Crinklaw wrote that Comet ISON is the least impressive of the lot. I'm not sure I would agree, but there's no doubt at all which is best. Comet Lovejoy (C/2013 R1) is a real humdinger — almost as bright now as Comet ISON was forecast to be -- which is to say, about 10 times brighter than ISON actually is. This morning Lovejoy was in the same binocular field of view with M44, the Beehive Cluster — an incredible view. The comet is big, bright, and gorgeous, with a diffuse but fairly long tail.
Moreover, Comet Lovejoy C/2013 R1 (not to be confused with other famous comets discovered by Terry Lovejoy) is very well placed in the predawn sky, high in the southeast near the Leo/Cancer border. If you prefer staying up late to getting up early, Lovejoy is reasonably high in the east by 1 a.m. at mid-northern latitudes.
ISON is feeble by comparison, though it has indeed improved a lot in the last few weeks. I swept it up easily in my 7-inch Dob at 28X, and it was quite handsome at 120X, with a 3' head and a bright, starlike pseudonucleus. I didn't see any sign of a tail. I tried and failed to see it with my 10x30 binoculars; it might be possible in a darker sky.
Comet 2P/Encke is painfully low at the onset of astronomical twilight, but also quite handsome. Its head is considerably smaller but brighter than ISON's, standing out well against the brightening sky.
Comet C/2012 X1 (LINEAR) gave me the most trouble; it is both low in twilight and very diffuse — a bad combination! If you're going to skip any one of these four comets, this is the one to skip.
I drove to my astronomy club's observing field near the edge of Boston's suburbs for these observations. It's pretty dark as suburbs go; on the other hand, the comets happened to be in precisely the worst spot in the sky, right above the glow of Boston. So I think that ISON should be pretty easy to spot in a telescope now from a typical suburb, assuming you have a low eastern horizon. And Comet Lovejoy should be easy to spot almost anywhere.
Click here to download a detailed, full-page chart of both comet's paths for the next week, before the full Moon makes the comets difficult to see. The ticks on the charts are for 0:00 Universal Time, roughly a half day before morning twilight in the Americas.