" The highlight of ISON's apparition will certainly occur in mid-December. The comet will then be visible at both dawn and dusk, a third of the way up from the eastern horizon just before sunrise and low in the west soon after sunset. Because Comet ISON makes its first trek in from the distant Oort Cloud, its nucleus should be especially ice-rich, leading to the formation of a long tail. We can only guess just how long it will be, but will likely reach from southern Hercules to the handle of the Big Dipper (almost a quarter of the celestial sphere)." http://www.nightskyinfo.com/ison/#december http://www.nightskyinfo.com/ison/ison_december.htm
Comet ISON would be *north* of the sun, heading up into Draco by the end of December. Thus (like the circumpolar stars) it can be visible both in the evening and in the morning.
Tim
-----Original Message-----
From: Phys-l [mailto:phys-l-bounces@phys-l.org] On Behalf Of Bruce Sherwood
Sent: Thursday, November 14, 2013 11:01 AM
To: Phys-L@Phys-L.org
Cc: njaapt@mail.aapt.org
Subject: Re: [Phys-L] Comet ISON
It's not possible for a comet visible before sunrise (so west of the Sun) to also be visible after sunset (east of the Sun). In fact, comet ISON will be visible only just before sunrise.