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One video and one visual chord was observed across this minor planet by Dave Gault in NSW. To do so Dave set up his video system to run unattended, while a second site for visual observation was set up 6.9 km south measured perpendicular to the occultation track. Other observers in the Sydney region, who would almost certainly have seen an event, were clouded out.
View the updated prediction.
To view an animated gif of Dave's Dufour observation visit: http://www4.tpgi.com.au/users/daveg/astrovideos/dufour.gif.
The plots below show two (of several possible) solutions for Dave Gault's observations. Although his chords are reasonably well separated, there is still considerable ambiguity in the result; only one further chord would have been needed to resolve this and it is unfortunate that Sydney observers were clouded out.
Solution: ~30 x ~55 km
Solution: ~40 x ~67 km:
The following plot shows the relative locations of the other observers who supplied reports. As can be seen, Jeff Byron would most certainly have seen an occultation if it had been clear:
Observers: 1 Dave Gault A, Hawkesbury H. Aust (Video) 2 Dave Gault B, Hawkesbury H. Aust (Visual) 3(M) A.Brakel, Downer, ACT, Australia 4(M) P. Litwiniuk, Pakenham, Australia 5(M) D.Watson, Whakatane, NZ 6(C) J. Byron, Sydney, Australia 7(C) R.Giller, Sydney, Australia M = Miss; C = Cloud
Dave is to be congratulated on his novel means of observing. This is the first time one single observer in Australasia has recorded two chords from widely separated sites.
Observational Data:
Observer's Name : Dave Gault (Video)
Aperture (cm) : 25
Focal length (cm) : 122
Type (e.g. SCT; Newtonian) : EQ Newtonian
Magnification : PC164C video camera at newtonian focus
Observing site name : Hawkesbury Heights, NSW
Longitude (East +ve) : 150 38.4621
Latitude (South -ve) : -33 39.8641
Height above Sealevel (metres) : 283.7
Datums : WGS84 and MSL
Sky Transparency (Delete two) : Good
Star Image Stability (Delete two): Good
Other Conditions: :
Time Source (e.g. WWV, VNG) : GPS
Recording method (e.g. tape) : KIWI VTI
Could you see the Asteroid? : NO
Approx. Limiting Magnitude : 12.7
: UT Time | PE | Accuracy | Remarks
Started Observing : 13.10
Disappearance At : 13:58:46.37 | 0 | 0.008 | 3 fields to disapear
Reappearance At : 13:58:49.59 | 0 | 0.008 | 3 fields to reapear
Stopped Observing : 14:10
ADDITIONAL COMMENTS:
This station was left to run unattended while I setup station B 6.9km south. (perpendicular to path)
Observer's Name : Dave Gault (Visual)
Aperture (cm) : 17
Focal length (cm) : 120
Type (e.g. SCT; Newtonian) : DOB
Magnification : 40
Observing site name : Linden, NSW
Longitude (East +ve) : 150 31 14.3
Latitude (South -ve) : -33 42 44.7
Height above Sealevel (metres) : 486.6
Datums : WGS84 and MSL
Sky Transparency (Delete two) : Good
Star Image Stability (Delete two): Good
Other Conditions: :
Time Source (e.g. WWV, VNG) : GPS
Recording method (e.g. tape) : KIWI PC
Could you see the Asteroid? : NO
Approx. Limiting Magnitude : 11.5
: UT Time | PE | Accuracy | Remarks
Started Observing : 13:56
Disappearance At : 13:58:46.87 | 0.40 | 0.20 | Fingers were cold
Reappearance At : 13:58:49.61 | 0.40 | 0.10 |
Stopped Observing : 14:00
ADDITIONAL COMMENTS:
This station was 6.9km south of my unattended station A (perpendicular to path)
Observer's Name : Albert Brakel
Aperture (cm) : 20 cm
Focal length (cm) : 200 cm
Type (e.g. SCT; Newtonian) : SCT
Magnification : 77x
Observing site name : Downer (home)
Longitude (East +ve) : +149 08' 14"
Latitude (South -ve) : -35 14' 32"
Height above Sealevel (metres) : 575 m
Geodetic Datum (e.g.WDD84,NZ1949): AGD66
Height Datum (if known) : Australian Height Datum (AHD)
Sky Transparency (Delete two) : Good
Star Image Stability (Delete two): Good
Other Conditions:
(Wind, Clouds, Lights, etc.): Clear sky, moderate suburban light pollution
Time Source (e.g. WWV, VNG) : WWVH
Recording method (e.g. tape) : Tape
Could you see the Asteroid? : No
Approx. Limiting Magnitude : ca 11.5
| Estimated |
Universal Time | Reaction | Accuracy, Remarks
h m s | Time (sec) |
Started Observing : 13:52:37
Stopped Observing : 14:05
List all Interruptions to Observing:
(FORMAT --> __:__:__._ - __:__:__ _____________________)
FROM TO REASON
Break 1: 13:54:00 - 13:54:39 Double-checking star's identity
Break 2: 13:55:00 - 13:55:25 Time check
ADDITIONAL COMMENTS:
Star clearly visible at all times. Radio reception poor, but a bit better than the previous night.
Observer's Name : Peter Litwiniuk
Aperture (cm) : 20
Focal length (cm) : 203
Type (e.g. SCT; Newtonian) : SCT
Magnification : 81x
Observing site name : Pakenham
Longitude (East +ve) : 145 29 00
Latitude (South -ve) : -38 04 01
Height above Sealevel (metres) : 62
Geodetic Datum (e.g.WGS84,NZ1949): GDA94
Height Datum (if known) :
Sky Transparency (Delete two) : Good
Star Image Stability (Delete two): Good
Other Conditions:
(Wind, Clouds, Lights, etc.): calm, humid, cloudless
Time Source (e.g. WWV, GPS) : www.time.gov
Recording method (e.g. tape) : manual
Could you see the Asteroid? : no
Approx. Limiting Magnitude : 12
| Estimated |
Universal Time | Reaction | Accuracy, Remarks
h m s | Time (sec) |
COLUMN FORMAT TO USE---> __:__:__._ _._ _________________)
Started Observing : 13 56 00
Stopped Observing : 14 06 45
ADDITIONAL COMMENTS:
No occultation seen.
Observer's Name : Diana Watson
Aperture (cm) : 20
Focal length (cm) : 200
Type (e.g. SCT; Newtonian) : Celestron 8
Magnification : times
Observing site name : Whakatane
Longitude (DD MM SS ; East +ve) : 176 51 50.7
Latitude (DD MM SS ; South -ve) : -37 55 18.5
Height above Sealevel (metres) : 2.8 metres
Geodetic Datum (e.g.WGS84,NZ1949): WGS84
Height Datum (if known) :
Sky Transparency (Delete two) : Good Fair Poor
Star Image Stability (Delete two): Good Fair Poor
Time Source (e.g. WWVH, GPS) : WWVH
Recording method (e.g. tape) : tape recorder
Observational Data - Star not seen:
Jeff Byron: As I told David by phone yesterday, I attempted this event but was thwarted by
cloud. Heavy cloud during the preceding day made me less than hopeful. However, at (Event time - 45 minutes)
there was a very large clear patch of sky overhead. But by (Event time - 20 minutes) the clouds had
returned (100%) and remained that way until after the event time.
Roger Giller: Weather conditions (8/8 cirrus) and Public Open Night commitments conspired to prevent
me setting up to try this one. Sounds like I would have got valuable confirmation, or even a positive
observation, if I had.
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