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OCCULTATION OF TYC 6856-01519-1 BY (1071) BRITA
2005 AUGUST 3


An occultation was seen by John Talbot observing from Waikanae, north of Wellington, NZ. No events were reported from Pukerua Bay to the south or Wanganui to the north.

View the updated prediction and a magnified plot.

Observers:
  1    J. Talbot, Waikanae, NZ              
  2(M) R. Hudson, Pukerua Bay, NZ           
  3(M) R. Wright, Wanganui, NZ              
M = Miss

Brita occultation - 2005 August 3

Discussion:

The circle above is plotted at the expected 50 km diameter of Brita.

For the Pukerua Bay observations, the star was on the limit of detectability and the observer feels that there is an 80% chance that an event did not occur there. If this was the case then the Waikanae chord must have been across the southern half of the asteroid otherwise an occultation of a few seconds would have been seen at Pukerua Bay. These data indicate that the path of this event shifted to the north by roughly one half path-width, meaning that the event would also have been seen in Otaki, Te Horo, Levin and Martinborough. However observers at Te Horo and Martinborough experienced equipment problems at the critical time.

Observational Data:

Observer's Name                  : John Talbot
Aperture (cm)                    : 10cm
Focal length (cm)                : 1400cm
Type (e.g. SCT; Newtonian)       : Newtonian, Saxon on Equatorial mount
Magnification                    : 56x (25mm eye piece)
Observing site name              : 3 Hughes St, Waikanae Beach
Longitude (DD MM SS ; East +ve)  : 175 01 56.6
Latitude (DD MM SS ; South -ve)  : -40 51 19.1
Height above Sealevel (metres)   : 5m
Geodetic Datum (e.g.WGS84,NZ1949): WGS84
Sky Transparency (Delete two)    : Good
Star Image Stability (Delete two): Good
Other Conditions:  Clear , No wind, some suburban lights
Time Source (e.g. WWVH, GPS)     : WWV 10MHz
Recording method (e.g. tape)     : Tape
Could you see the Asteroid?      : no
Approx. Limiting Magnitude       :  ~11 to 12
                                          | Estimated  |
                           Universal Time | Reaction   | Accuracy, Remarks
                              h  m  s     | Time (sec) | 
Started Observing          : 07:00:00
Disappearance At           : 07:06:28.5 - 0.4 -0.5 = 07:06:27.6
Reappearance At            : 07:06:33.3 - 0.4 -0.5 = 07:06:32.4
Stopped Observing          : 07:10:00
Occultation Duration       : 4.8 sec

Was your reaction time (also known as Personal Equation) subtracted from 
any of the above timings?  : yes
If YES, state value        : 0.5 for star change to shout and 0.4 for shout to stopwatch

ADDITIONAL COMMENTS: 
From 95% cloudcover at 5:45 it cleared to a perfect but chilly night by 6:30. It took me about 
20 minutes to find target. I am certain I was looking at star shown in detailed finder charts. 
The result is about 1 minute later than forecast but I am certain I could see the star all of 
minute 5. Revised reaction times after testing with a reaction time program


Observer's Name                  : Rick Hudson + Gordon Hudson
Aperture (cm)                    : 30
Focal length (cm)                : 300
Type (e.g. SCT; Newtonian)       : Cassegrain
Magnification                    : n/a
Observing site name              : Kotipu Place Observatory
Longitude (DD MM SS ; East +ve)  : +174 52 54.36
Latitude (DD MM SS ; South -ve)  : -41 02 27.61
Height above Sealevel (metres)   : 108.5
Geodetic Datum (e.g.WGS84,NZ1949): NZ1949
Height Datum (if known)          : MSL
Sky Transparency (Delete two)    : Good
Star Image Stability (Delete two): Poor
Other Conditions:
     (Wind, Clouds, Lights, etc.): Calm
Time Source (e.g. WWVH, GPS)     : GPS
Recording method (e.g. tape)     : Video camera + GPS time overlay
Could you see the Asteroid?      : No
Approx. Limiting Magnitude       : 11 (with camera)
                                          | Estimated  |
                           Universal Time | Reaction   | Accuracy, Remarks
                              h  m  s     | Time (sec) | 
Started Observing          : 07:02:38
Stopped Observing          : 07:10:53


ADDITIONAL COMMENTS: 
Star on the limit of detectability with equipment combination. About 80% certain
that no occultation occurred during observing period.


Observer's Name                  : Ray Wright
Aperture (cm)                    : 25.4 
Focal length (cm)                : 101.6 
Type (e.g. SCT; Newtonian)       : Schmidt-Newtonion  
Magnification                    : 39x 
Observing site name              : Brunswick driveway 
Longitude (DD MM SS ; East +ve)  : 175°01'12.6" East 
Latitude (DD MM SS ; South -ve)  : 39°50'45.5" South
Height above Sealevel (metres)   : 165 
Geodetic Datum (e.g.WGS84,NZ1949): WGS 84 
Sky Transparency (Delete two)    : Good
Star Image Stability (Delete two): Good
Other Conditions:  
     (Wind, Clouds, Lights, etc.): Cloud 
Time Source (e.g. WWVH, GPS)     : 
Recording method (e.g. tape)     : 
Could you see the Asteroid?      : 
Approx. Limiting Magnitude       : 
                                          | Estimated  |
                           Universal Time | Reaction   | Accuracy, Remarks
                              h  m  s     | Time (sec) | 
Started Observing          : 07h 03
Stopped Observing          : 07h 08 

Return to 2005 occultation results



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