Comet C/2010 X1 Elenin is coming. Right now it is magnitude +19, but initial estimates indicate it could be as bright as magnitude +3.4 in early September. Its orbital plane is inclined only 1.85° to the ecliptic. Perihelion is expected on 2011 SEP 05 (Labor Day) with passage nearly midway between the Earth and Sun on SEP 14.
I’ve created three related graphics. The first plots the comet in equatorial coordinates from JUL 25 to NOV 16. The second plots the comet in horizontal (alt-az) coordinates from Chicagoland during its evening apparition from JUL 25 to SEP 04. The third plots the comet in horizontal coordinates from Chicagoland during its morning apparition from SEP 21 to NOV 17. They can be seen at http://www.curtrenz.com/astronomical
Photos and descriptions of the comet would be welcome additions to this thread.
EDIT: This is an old thread of mine with stale information that someone bumped up today. I had created a later version on this subject with updated data: http://www.bautforum.com/showthread....-14-Opposition