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A 39.11 second occultation was recorded by John Broughton at Reedy creek, Qld, Australia, using the CCD drift-scan technique.
View the updated prediction.
Observers: 1 J. Broughton, Reedy Crk, Australia
Discussion:
The circle above is plotted at the expected 468km diameter of Vesta. It can immediately be seen that John Broughton must have been relatively close to the centre line of the event, which has moved slightly north in comparison to the updated prediction. Further, John's 39.11 sec event is longer than the maximum expected duration of 33.0 seconds indicating Vesta's axis in the occultation direction is somewhat longer than the assumed diameter.
The plot below shows the data as analysed by John's Scanalyser software.
Observational Data:
Observer's Name : John Broughton
Aperture (cm) : 50.1
Focal length (cm) : 138
Type (e.g. SCT; Newtonian) : Newtonian
Magnification : CCD drift-scan at 3.8 pixels per second
Observing site name : Reedy Creek, Gold Coast
Longitude (East +ve) : +153 23' 49"
Latitude (South -ve) : -28 06' 36"
Height above Sealevel (metres) : 66
Geodetic Datum (e.g.WDD84,NZ1949): AGD66
Sky Transparency (Delete two) : Good
Star Image Stability (Delete two): Good
Time Source (e.g. WWV, VNG) : WWVH.
Recording method (e.g. tape) : Tape.
Could you see the Asteroid? : Only combined light monitored though
asteroid is visible during occultation.
Approx. Limiting Magnitude : 14
| Estimated |
Universal Time | Reaction | Accuracy, Remarks
h m s | Time (sec) |
Started Observing : 8:59:23.42 n/a 0.01
Disappearance At : 9:00:07.84 n/a 0.10
Reappearance At : 9:00:46.95 n/a 0.10
Stopped Observing : 9:01:24.41 n/a 0.01
Duration : 39.11
ADDITIONAL COMMENTS: CCD drift-scan. Measurements done with Scanalyser. The observed magnitude drop was 0.28 instead of
the 0.11 predicted. Fortunately the seeing variations were only half of the magnitude drop and this led to a relatively
good measurement accuracy for an event such as this.