2003 AZ84  03/02/2012

*See updates at the bottom of the page*


*See updates at the bottom of the page*
finding charts in pdf and maps (01/Feb)

Dark gray is night and light gray is astronomical twilight (Sun at less than 18° below the horizon).
Shadow moves from right to left, each red dot is separated by one minute, the nominal occultation time on the map, is to the big red dot.
See finding charts bellow.
Doted lines are the estimated error of the star position, but the error can be bigger due to ephemeris offset!

Star J2000 coordinates:
RA 07 45 54.765
DEC +11 12 43.150
Day coordinates:
RA     07 46 37.296
DEC +11 10 44.092

Star R mag 15.1
Star K mag 14.2
Magnitude drop in R 4.9
Max. duration if 750km  diameter 30s
 Max duration for the satellite if 68km. 2.7s

Observation tips:

Absolute time accuracy is essential to connect together all the observations after the fact. Check the time of your computer with many sources (phone talked hour, different internet sites, ideally with a GPS). As images should be acquired for a long time (10min at least), its advised to check the registered time right after and right before the integrations, so if there is a drift, we can correct it by having the difference.

Beware of the dead time between the images. If you manage an exposure time of 1 sec (for example), but have a read time of 2 sec, then there is a 67% chance that you miss the dis(re)-appearance of the star. So it's better to have, say, a 4 sec integration, so you have  67% chance to get the occultation in one of your exposures.

Finding charts:

12x4 arc min FOV
, made by Jean Lecacheux.
With a
1x1 arc minute square window optimally rotated, and with some R magnitudes from the GSC v.2.2/2.3 catalog, North is up east is right.

15 x 15 arc min FOV from DSS R band.
Click here for a fits file of this image.

7 x 2 degrees FOV, by J. Lecacheux.
The TNO trajectory is indicated, from left to right each day starting 01/01/2012.
The square have 12x12 arc minutes, centered on the occultation star. The "biggest" star is 11 Canis Minoris with a 5.2 magnitude.

Finding charts in pdf format with magnitudes: [60°, 10° and 1°] and [30x15arc min

Astrometric Updates

With observations of the star performed from OPD (Itajubá/BR), Julio Camargo obtained a new position of the star.

2012-02-03T19.803_OPDstar_2003AZ84.jpgupdated on: [19/01]

François Colas, Jean Lecacheux have observed the star and 2003 AZ84 from Pic du Midi on 17th January. With reductions from Raoul Behrend, J. Lecacheux obtained the following map.

José Ortiz and his group observed the star to be occulted and the TNO from La Hita, from 18th to 20th January, which gives the following map.

José Ortiz and his group observed the star to be occulted and the TNO with ASH2 telescope, from 16th to 25th January, and obtained the following map.

José Ortiz and his group also obtained two nights of data with the 50cm telescope at the Observatorio Astronómico de Cala d´Hort, Ibiza, which gives the following map.

J. Lecacheux has calculated the average of all offsets obtained at Pic du Midi from 17th to 23th January, and a weighted average of all star positions obtained (some used on the maps above), and obtained this prediction.

With the same positions, I generated this maps where some of the stations that are collaborating.