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An occultation was timed by Ross Skilton at Tayforth, Wanganui, NZ.
View the updated prediction.
Observers: 1 R. Skilton, Tayforth, NZ 2(-) J. Burt, Gisborne, NZ 3(M) B. Loader, Darfield, NZ 4(M) T. Butt, Te Horo, NZ 5(C) A. Dodson, Waitara, NZ 6(P) Predicted Track M = Miss C = Cloud
Discussion:
The circle above is plotted at the expected 166km diameter of Alexandra.
Ross Skilton in Wanganui timed a 4.0 second occultation, this being somewhat shorter than the expected maximum 5.7 second duration assuming a circular asteroid. Thus, Skilton was some distance from the centre of the track. John Burt in Gisborne also saw the event, but owing to a problem his event timings were lost.
The negative observations of Loader and Butt however provide constraints which indicate that Skilton's chord was nearer the eastern side of the asteroid, thus showing that the actual event track was very close to that of the prediction. The position of Andy Dodson in Taranaki is also plotted; he would have seen an event if he had not been clouded out.
Observational Data:
Observer's Name : Ross Skilton
Aperture (cm) : 20
Focal length (cm) : 203
Type (e.g. SCT; Newtonian) : SCT
Magnification : 32mm EP giving 64x
Observing site name : Tayforth
Longitude (DD MM SS ; East +ve) : 174 59 55.2 East
Latitude (DD MM SS ; South -ve) : -39 54 55.3 South
Height above Sealevel (metres) : 37
Geodetic Datum (e.g.WGS84,NZ1949): WGS84
Height Datum (if known) : MSL
Sky Transparency (Delete two) : Poor
Star Image Stability (Delete two): Fair
Other Conditions:
(Wind, Clouds, Lights, etc.): ~60% low cloud cover, dark ,light breeze
Time Source (e.g. WWVH, GPS) : WWVH
Recording method (e.g. tape) : Stopwatch
Could you see the Asteroid? : No
Approx. Limiting Magnitude : 12.5
| Estimated |
Universal Time | Reaction | Accuracy, Remarks
h m s | Time (sec) |
Started Observing : 10:31:00
Disappearance At : 10:32:8.8
Reappearance At : 10:32:12.8
Stopped Observing : 10:33:00
Was your reaction time (also known as Personal Equation) subtracted from
any of the above timings? : Yes
If YES, state value : 0.4 sec D&R
If you could tell, in which direction did the asteroid pass relative to
the star (Delete three) : na
ADDITIONAL COMMENTS: Poor weather conditions prevented me from centering the star in the video cam
so I reverted to a stopwatch synced to WWVH at 10.27UT.
Observer's Name : John Burt
Aperture (cm) : 20cm
Focal length (cm) : 1200cm
Type (e.g. SCT; Newtonian) : Newtonian
Magnification : 48x
Observing site name : Possum Observatory, Patutahi
Longitude (DD MM SS ; East +ve) : 177 54 00
Latitude (DD MM SS ; South -ve) : -38 37 02
Height above Sealevel (metres) : 1
Geodetic Datum (e.g.WGS84,NZ1949):
Sky Transparency (Delete two) : Good
Star Image Stability (Delete two): Good
Other Conditions:
(Wind, Clouds, Lights, etc.): Good
Time Source (e.g. WWVH, GPS) :
Recording method (e.g. tape) :
Could you see the Asteroid? : no
Approx. Limiting Magnitude : 13
| Estimated |
Universal Time | Reaction | Accuracy, Remarks
h m s | Time (sec) |
Started Observing : 10:25:00
Disappearance At : 10:32:?? Problems with timing – see comments
Reappearance At : 10:32:?? Approx 3 seconds
Stopped Observing : 10:38:00
Was your reaction time (also known as Personal Equation) subtracted from
any of the above timings? : no
ADDITIONAL COMMENTS: I very diligently did the timings, but pushed the wrong button on the timer I was using
(tape batteries ran flat *sigh*) and lost the record. The disappearance was approximately 3 seconds, but thats
just a very rough guessimate. I know it was between 10:32:00 and 10:33:00 UT as I heard JD in the observatory
shout out a time-stamp.
Observer's Name : Brian Loader
Aperture (cm) : 25.4
Focal length (cm) : 250
Type (e.g. SCT; Newtonian) : SCT
Magnification : n/a
Observing site name : Darfield
Longitude (DD MM SS ; East +ve) : +172° 06' 24.4" E
Latitude (DD MM SS ; South -ve) : -43° 28' 52.9" S
Height above Sealevel (metres) : 210
Geodetic Datum (e.g.WGS84,NZ1949): WGS84
Height Datum (if known) : MSL
Sky Transparency (Delete two) : Good
Star Image Stability (Delete two): Poor
Other Conditions:
(Wind, Clouds, Lights, etc.): Occasional wind shake
Time Source (e.g. WWVH, GPS) : GPS/KIWI
Recording method (e.g. tape) : VIDEO
Could you see the Asteroid? : no
Approx. Limiting Magnitude : 10.8
| Estimated |
Universal Time | Reaction | Accuracy, Remarks
h m s | Time (sec) |
Started Observing : 10:28
Stopped Observing : 10:36
ADDITIONAL COMMENTS: No event. Poor unstable image.
Observer's Name : Terry Butt
Aperture (cm) : 250
Focal length (cm) : 1600
Type (e.g. SCT; Newtonian) : SCT
Magnification : ?
Observing site name : Te Horo
Longitude (DD MM SS ; East +ve) : 175 07 26.53 E
Latitude (DD MM SS ; South -ve) : 40 48 47.31 S
Height above Sealevel (metres) : 52
Geodetic Datum (e.g.WGS84,NZ1949): WGS84
Height Datum (if known) : MSL
Sky Transparency (Delete two) : Good
Star Image Stability (Delete two): Fair
TIMINGS: (PLEASE REPORT IN UNIVERSAL TIME)
Time Source (e.g. WWVH, GPS) : Kiwi OSD
Recording method (e.g. tape) : VCR
Could you see the Asteroid? : No
Approx. Limiting Magnitude :
| Estimated |
Universal Time | Reaction | Accuracy, Remarks
h m s | Time (sec) |
Started Observing : 10 30 00
Disappearance At : NO CHANGE SEEN IMAGE RATHER UNSTABLE
Stopped Observing : 10 34 00
ADDITIONAL COMMENTS: Clouding over at 1040 UT
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