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Central flash: science

First occultation: TYC 1343-1615-1
14 Nov. 2003, ~ 00:10 UT

Second occultation: TYC 1343-1865-1
14 Nov. 2003 ~ 07:00 UT

Summary of sites

Preliminary results

Occultations in 2003: Titan

The Titan central flash observer on 3 July 1989 at Meudon Observatory

Claudio Martinez, from Argentina, discovered in October 2002 two important stellar occultations by Titan.

Coincidentally, these two occultations will take place on the same day : 14 November 2003, and will involve relatively bright stars: V= 8.6 and V= 10.7, respectively, while Titan has V ~ 8.4. Because both stars are red, the contrast will be enhanced in the red and infrared.

Scientific interest, circumstances, visibility, astrometry, photometry, etc... of these two events are described below. You may find complementary information in Leslie A. Young's site (, Southwest Research Institute in Boulder) about the second event, and about other planetary occultations as well.

Another site with a good deal of information (choice of cameras, filters, tests to be performed, etc... ) is the IOTA site (European section).

Finally, Jay Anderson's site provides information on the weather prospects in November at various places in the world.

AN ESSENTIAL GENERAL NOTE FOR OBSERVERS: due to the significant contribution of Titan in the total flux Titan + star (for both events), it is CRUCIAL to have a SEPARATE photometry of the star and Titan. Lack of good calibrations was one of the main limitations after the famous 28 Sgr Titan occultation of July 1989.

A good calibration can be achieved by measuring Titan and the occulted star SEPARATELY before or after the event, assuming that Titan does not vary in between. Another useful trick is to measure ANOTHER reference star simultaneously during the event. This can easily be done, as the two occulted stars are 45 arcsec apart, so one can be used as the reference for the other.

This has the advantage of (1) providing a transparency monitoring of the sky during the event and (2) allowing for an independent photometric calibration, by measuring again the occulted star against the reference star before or after the event (thus avoiding potential problems, should Titan's brightness vary from one day to the other).

Scientific interest of the central flash

First occultation: TYC 1343-1615-1
14 Novembre 2003 around 00:10 UT
(mainly Indian Ocean and Southern Africa)

Second occultation: TYC 1343-1865-1
14 Novembre 2003 around 07:00 UT
(mainly SW Europe, N. Africa, N. and Central Americas)

Summary of sites, telescopes, detectors for both occultations,
to know about the various instruments and people involved in these observations

About the background photo: volcanoes, sheep and shepherds in the Atacama desert, August 2002.

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