Two misses were recorded for this event.

View the updated prediction.

Observers:
  1(M) R Groom,Stoneville, Western Australia
  2(M) D Gault,Hawksbury Heights,NSW,AU
  3(P) Prediction
    

Discussion:

The circle above is plotted at the expected 1186 km diameter of Charon. At first it was thought that both observers may have had positive dips. However having looked at both sets of data and put the csv files through the Occular analysis program we came to the conclusion that in both cases it is much more likely that we have noise rather than a real signal.

Dave's data looked the most promising in that the duration was near the predicted 69 seconds and close to predicted time, however:
- Magnitude drop was measured at only around 0.05 as against the predicted 0.61
- Further blocking was tried to improve S/N ratio but while there was a nice candidate very close to the expected time the mag drop does not improve so we had to rule that out.

Roger's data had some interesting looking drops however:
- It also suffered very low magnitude drop that looks even smaller at around 0.015
- The most promising "event" lasted about 3.5 minutes as against predicted 69 seconds

No other reports have been received at this stage so I believe that we must conclude that both observed misses.

Observational Data:

Observation details for MP (134340) Charon
By Star
On 2010-05-16  at 15:04:00.0
_______________________________

Observer   Roger Groom
Location   Stoneville, Western Australia
Longitude  -116:10
Latitude   -31:52
Altitude   285 m
Datum      WGS84
Telescope SCT including Cass and Mak
Aperture   30 cm
Seeing     Slight flickering Clear
Timing     other Video, photo or photoelectric
Disappearance  15:59:11.07
Reappearance   16:04:40.30
Comments: Timed using Beepsync to synchronise PC clock 2 hours prior to
occultation occuring.
5 second exposures used, times quoted are start of the exposures.

Observation details for MP (134340) Charon
By Star         USNO-1B 718-0730960
On 2010-05-16  at 15:04:00.0
_______________________________

Observer   Dave Gault
Location   Hawkesbury Heights,NSW,AU
Longitude  +150:38
Latitude   -33:39
Altitude   286 m
Datum      WGS84
Telescope Newtonian
Aperture   25 cm
Seeing     Steady Thin cloud < 2
Timing     GPS - time inserted Video with frame analysis

Missed

Comments: It was very cloudy 1/2 hour beforehand but it was apparent that it
might clear.  I started slewing with only 9 minutes to go,
and managed to grt on target in time.
Probably a miss, cloud affected or a not detected.
Light curves, a screenshot and .csv file included with this report.