- The Chicago Astronomer -
Copyright 2004-2014 All rights reserved by Joseph Guzman Administrator/Founder/Chief Astronomer.
All text and images are the property of the original authors/artists and shall
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I’ve created an Asteroid 2005 YU55 timetable with topocentric data in half-hour increments during the night of close passage specifically for the location of Chicago’s Adler Planetarium. It should well serve all Chicagoland observers. And I’ve added a daily chart in current equatorial coordinates in addition to the previously existing still and animated overhead views. All four can be seen at www.CurtRenz.com/asteroids
I calculate that when viewed from Chicago at the time of closest approach, the asteroid will appear to be traversing the background stars at 8.5 arcseconds per second of time, or 8.5 arcminutes (0.14°) per minute of time. A Full Moon is about 0.5° wide, and the asteroid will be sweeping that angular width in about 3.5 minutes.
For observers at Chicago’s Adler Planetarium, I calculate that the asteroid will appear to pass nearest the first magnitude star Altair at an angular distance of 1.846°, position angle 161.595° and zenith angle 156.933° on November 8 at 16:44:22 CST. That will be only seven minutes after sunset for that location. Position angle is measured counterclockwise from celestial north. Zenith angle is measured counterclockwise from the zenith.
For those using geocentric charts, you're reminded that parallax is a significant factor for such a close object. My timetable is specifically for the location of the Adler, although it should suit all Chicagoland observers: www.CurtRenz.com/asteroids