(This report was originally posted on the International Occultation Timing Association (IOTA) newsgroup).
I successfully observed the (85) Io occultation tonight from my driveway in Calgary (114°05'35"W, 50°59'26"N, elevation 1081m) with my Meade 8" LX200GPS and PC164C video camera with f/3.3 focal reducer. Conditions were perfect. Perfect, that is, except for WWV reception. I was doing some pretty fancy footwork with the shortwave radio, trying to get good reception (I don't want to guess what the neighbors were thinking of this), and so I wasn't actually looking at the TV screen at the time of the occultation. After recording a few minutes past the event, I played back and thought I could see something of the 0.4 mag. drop.
After packing up, I used a paper and hole punch to isolate on the screen the minor planet and a nearby star of the same brightness, then replayed the tape a number of times. The brightness change was subtle, but the following events seem to be real:
disappearance: 04:08:12.5 UTC ± 0.4 sec reappearance : 04:08:22.5 UTC ± 0.6 sec duration : 10.0 secSince I was fairly close to the predicted south limit, it appears there was a south shift (similar to last December's (334) Chicago occultation). The predicted mid-time, however, seems accurate to within a few seconds.