Two "probable" misses were recorded for this event.
View the TT14 prediction.
As can be seen from the prediction the predicted mag drop is only 0.10m and worse in red. The asteroid is brighter than the star so we can expect a light curve where the signal may well be swamped by the noise.
Observers: 1(M) D Gault,Kuriwa Observatory, NSW, AU 2(M) T Barry,Werrington Downs, NSW 3(P) Prediction, TT14 27 Sept
The circle above is plotted at the expected 206 km diameter of Amphertrite. The DAMIT 3D model has been overlaid on the measured ellipse and shows that the circle is a reasonable fit.
The figure below shows the AOTA attempt to locate a signal in light curve of Dave's observation.
There is an interesting small blip of about 2 seconds long (c.f. 10.4 predicted max)
that it is tempting to think could be a graze.
However there is no sign of a corresponding dip that would be expected in Tony's nearby lightcurve below.
So with no definite positive chords we cannot say where the actual path was, so the circle has been plotted on the predicted path.
The point of this discussion is that very low mag drop events are probably not worth observing. And while we cannot assert that there was an event neither can we completely rule it out. See also the Juno event later this month where a mag drop of 0.2 was observed by Dave.
Observation details for MP ( 29 ) Amphitrite By Star UCAC4 306-198489 On 2014-10-01 at 10:52:22.0 _______________________________ Observer Dave Gault Location Kuriwa Observatory, NSW, AU Longitude +150:38 Latitude -33:39 Altitude 286 m Datum WGS84 Telescope SCT including Cass and Mak Aperture 30 cm Seeing Steady Clear Camera Type Grasshopper Express with ADVS ADVS Camera Delay 0 Timing GPS - time inserted Video with frame analysis Missed Comments: Predicted mag. drop = 0.06. Test Exposure of asteroid at T-20 minutes revealed both exposed OK @ 3.75 fps Confident that I can report a miss rather than a not detected. test image and .csv files included with report. _______________________________ Observer Tony Barry Location Werrington Downs, NSW Longitude +150:43 Latitude -33:44 Altitude 66 m Datum WGS84 Telescope SCT including Cass and Mak Aperture 25 cm Seeing Steady Clear Camera Type Grasshopper Express with ADVS ADVS Camera Delay 0 Timing GPS - time inserted Video with frame analysis Missed Comments: John, this in my opinion was a miss. Your opinion is always welcome.