The truth is that there are lots of serious measurements going on, and so far, unfortunately, comet ISON is not brightening like it was hyped, I mean hoped. ISON could end up being much like Panstarrs was: difficult to see with the naked eye. ISON does have a few advantages, however, including the fact that it’s path is almost perpendicular to the earth’s rotation. That means it will move high into the northern sky after it squeaks by the sun and remain visible all night. Whether ISON will survive its close encounter to incineration is open to interpretation. There is also a lot of conjecture whether the comet will have enough water and gas to spew out a great trail, or whether it will simply sizzle and fizzle. The solid line was one prediction that the comet would reach a brightness similar to the top 10 brightest stars.

The relative brightness of Comet ISON through Sept. 20, 2013. Click for the latest plot. Note how the latest measurements fall below the model.
Important Dates;
- October 1st: Closet Approach to Mars (early AM) Probably NOT visible to the naked eye.
- End of October: First possibility that the comet will be visible to the naked eye – before the comet swings around the sun.
- November 28th: ISON makes its closest approach to the sun.
- December 6th: ISON climbs far enough away from the sun that it might be visible.
- December 26h: ISON is closest to earth
- January 2014: ISON will be too dim to see by eye.
Thank you Steve for all this information! You are so professional! Wish you were here in Arizona!
My first ISON photo. Completely unimpressive on October 3, 2013.

A better image taken October 14, 2013 when Mars and Regulus were at conjunction (closest visual approach).