(85) Io final prediction

Last updated 1995 Dec 9

(85) Io will occult PPM 146634 on 1995/12/10 at 00:37:56.6 UTC (geocentric)

Prediction details. (21Kb). The event will be visible in a swath from central Arizona through central Kansas and lower Michigan. The asteroid should be at about V=11.5 and the star is 8.6 so the flux drop should be very large. For an assumed radius of 80 km, a central chord would last 17.5 seconds. The predictions are based on transit telescope measurements made at the US Naval Observatory Station here in Flagstaff. So far we have 15 measurements of the star and 18 measurements of the asteroid. The correction to the ephemeris is present uncertain by 0.066 arcsec in right ascension and 0.054 arcsec in declination. We have generated postscript plots of the entire track (307Kb) and a plot of the southwest US (221Kb). The western end of the track is defined by where sunset occurs at the time of the occultation. This means that observers in all of Arizona and most of New Mexico will have to fight strong twilight to be able to see the event. On the plot of the southwest US, there are a series of lines indicating the elevation of the Sun at the time of the occultation. The lines run from -6 degrees (civil twilight) to -16 degrees (nearly astronomical twilight). The catalog coordinates of the star are ra=03:31:01.445, dec=+07:11:54.05, J2000. Additional transit observations are being taken every night possible at USNOFS and updated predictions will be posted here.

The prediction team consists of Ron Stone at the US Naval Observatory providing transit measurements, Larry Wasserman at Lowell Observatory is processing the measurements and generating the predictions and plots, and Marc Buie, also Lowell Obs., is coordinating the collection and dissemination of information (like this WWW page). Direct comments and questions to Marc Buie.