International Occultation Timing Association

European Section 

Occultations by




Pluto, TNOs



Partners & Friends

Members login

Contact us :

Knaust-Str. 8
D-30459 Hannover


Occultations by Near Earth Asteroid 1036 Ganymed for 2011

Dear IOTA Members,

This year sees a favorable apparition for 1036 Ganymed, a near -Earth Asteroid (NEA) which, at 40 km diameter, the largest known of its class. The object is expected to become as bright as 8th magnitude in October and November. Steve Preston has posted path predictions for 39 occultations of stars by this asteroid that will occur between the end of this month (April) and the end of the year. This presents an opportunity to characterize this large NEA. In particular, it may be possible to produce a combined shape and ephemeris solution of the asteroid using a large number of occultation chords, lightcurves, and astrometry of the asteroid and the stars to be occulted. Radar observations are also expected to take place at opposition near the end of the year.

In support of this effort, we would like to issue a call for observations of as many of these occultations as possible and also astrometry and Ganymed and the target stars. A list of predictions is provided below along with the geographical region where the occultation occurs. Currently, the uncertainty in most of the occultation paths is of the order of the path itself, ie it is good given the relatively small size of the asteroid but it can be better. The predicted occultations are short, 1-4 sec in duration and the flux drop is typically about a magnitude. The durations become longer and the flux drop smaller as the asteroid approaches the Earth in the Autumn. For these reasons, video or drift scan observations are preferred over the visual method. Also, please note that the predictions will be refined as time passes so be sure to check the latest predictions before setting off on a trip to observe an occultation. Hopefully, this call will result in a sufficient critical mass of observations for a dedicated publication.

Clear Skies and Good Luck!

Apostolos Christou

Jan Manek

Steve Preston

April 2011

SE Australia

May 2011

W Europe

SE Australia


Eastern USA & Canada


Eastern USA & Canada

June 2011

Indonesia, Australia

Eastern USA & Canada

UK, Europe, Africa

Eastern USA & Canada

Indonesia, W Australia

Indonesia, E Australia

July 2011

S Europe, NW Africa

Japan, Indonesia

SE Asia

Germany, Austria, Italy, N africa

NE China, S Japan

August 2011

W Asia, Turkey, S Greece, Africa

W Asia, Turkey, S Greece, Africa


China, India


USA, Mexico

September 2011

N USA, S Canada

USA, Mexico

Canada, NW USA

NE Asia, N Japan

USA, Mexico (morning twilight)

Europe, Africa

Europe, Africa

October 2011

S Asia, Indonesia

N Europe, W Asia, Middle East

Russia, Mongolia, China, Indonesia, Australia

Canada, NE USA, S America

S Japan, Indonesia,

E Russia, S Japan, Indonesia

November 2011

N & E Europe, Turkey, Africa

Canada, W USA