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Update 01 December 2010

2002 TX300 stellar occultation
(night 12 to 13 December, 2010)

On 12 December 2010 around 16:25 UT (night of December 12th to 13th, 2010), the Trans-Neptunian Object "2002 TX300" -- a member of the Haumea family -- may occult a star with:
V ~ 17.4
R ~ 17.0
I ~ 16.4
K ~ 15.0
(see the Vizier output ).

The event could be visible from Indian Ocean and India, Asia, but also from Russia, Middle-East and possibly, E. Europe, see maps below.

Astrometric J2000 position of the star:
(Assafin et al, Rio de Janeiro group, update 29 Nov. 2010, based on data collected at Pico dos Dias, Brazil)

α= 00h 38mn 08.3699 sec
δ= +28d 36' 28.254"

The corresponding star apparent airless position of the day is:

α= 00h 38mn 44.9 sec
δ= +28d 40' 22"

Astrometric updates

We give below recent updates.


- the shadow on maps below moves from upper right to lower left.

- the larger dot is geocentric closest approach (corresponding to the time "h:m:s UT" given below the map).

- small dots are plotted every minute.

- the width of shadow is 290 km. This is based on a stellar occultation observed in October 2009, with two positive chords detected. Assuming a circular shape Elliot et al. 2010 (Nature, 17 June 2010) derive a diameter of 286 +/- 10km. Elongated or irregular shapes are not ruled our, though.

- 2002 TX300's offset in ra and dec are given in the upper right corner of map, wrt the JPL#13 ephemeris.

- the event may last for more than 20 seconds.

- Geocentric mid-time should between 16:25 UT, with an uncertainty of more than +/- 5 minutes. So, it would be wise to observe a minimum +/- 20 mn around specific predicted times.

- the star has V ~ 17.4, R ~ 17, I ~ 16, so that 1m-sized scopes are required. But if you think that you can make it with a smaller telescopes with a sensitive camera and several sec exposures, go for it!
(Remember that even with several sec exposures, usefull science can be derived: accurate size determination)

- if the download of your individual images is slow, say 5 sec, it is useless to have 5-sec exposures, as half the time will be lost in downloads ("dead times"). Then it is better to have, say 10-sec exposures or more, so that the probability that the dis(re)-appearance occurs during an exposure remains high. Remember that dead times may be a serious problem!

update 29 November 2010: images taken at Pico dos Dias, Brazil, analyzed by M. Assafin et al.:

Astrometric J2000 position of the star:
α= 00h 38mn 08.3699 sec
δ= +28d 36' 28.254"

2002 TX300 offset wrt JPL#13:
Δ α cos(δ)= 38.0 mas
Δ δ= -40.2 mas

Click on images for enhancement

update 03 December 2010: images taken at La Hita, Spain, analyzed by J.L. Ortiz:

Astrometric J2000 position of the star:
α= 00h 38mn 08.3706 sec
δ= +28d 36' 27.997"

2002 TX300 offset wrt JPL#14:
Δ α cos(δ)= -82.0 mas
Δ δ= -76.4 mas

Click on images for enhancement

Charts: left 30x30 arcmin, right: 5x5 arcmin

Click on images for enhancement

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