Getting Ready for Cosmic Hit
Expectation rises as time of impact on comet approaches
Three days before the NASA Deep Impact spacecraft will collide with Comet 9P/Tempel 1, most astronomers who will use all ESO telescopes at the La Silla Paranal Observatory in Chile, have now arrived at their respective duty station and are carefully putting the last hand to the preparation of their observations.
The scientists and instrument specialists are presently implementing the latest hardware setups, making the final checks of the automatic observing sequences and working out on a detailed schedule for the individual ESO telescopes operation during the coming nights.
Astronomers will start using the four 8.2m telescopes of the Very Large Telescope Array at Paranal and their many instruments, as well as the medium-sized telescopes at La Silla, from July 2, until five days after the impact, in what is most likely, on ESO's side, the most ambitious ground-based study of Comet 9P/Tempel 1.
On June 29, the astronomers met at the ESO Chilean Headquarters in Santiago to coordinate their action. Extensive discussions were held to prepare the observing sequences at the various telescopes, to arrange for fall-back solutions in case of problems, to set-up the data reduction and analysis procedures to be used and to outline the communication paths between the two teams at Paranal and La Silla as well as to the Deep Impact project and other associated teams.
The team will have regular videoconferences between the two observing sites in order to coordinate activities for the observations and to discuss results.
The first data/images from the campaign can be expected during the night of July 2 to 3, still two days before the impact. These observations will provide the reference dataset to be compared with the results after the impact.
The latest information of the comet indicates that it is fainter by a factor 2 (1 magnitude) than the predicted brightness. Comet Tempel 1 shows prominent but normal gas emission features and displays various coma jets. Two outbursts have occurred during the past two weeks.
Two observing programmes will perform imaging and spectroscopic studies for one week following the impact. They aim at studying the gas and dust components, in particular the material ejected as a result of the impact. More details on the observing campaign are available at http://www.eso.org/public/events/astro-evt/deepimpact/impact/obseso/ and http://www.eso.org/public/events/astro-evt/deepimpact/impact/obseso4/.
Just after the impact on July 4, the telescopes will start observing as soon as possible. With TIMMI2 on the 3.6-m ESO telescope at La Silla, it will be possible to observe in daylight, as TIMMI2 performs infrared observations. Images will thus be available from around 16:00 Chilean Time, or 22:00 in Garching. The images taken with the other telescopes - at La Silla and Paranal - will start as soon as it is dark enough, i.e. when twilight ends in Chile, i.e. around 19h30 Chilean Time, i.e. 01:30 am in Garching on July 5. The images will be processed in almost real time in Chile by the astronomers and then made available through the Web site.
The ESO Headquarters in Garching (Germany) will be open to the media representatives on July 4 and 5. A detailed plan of scheduled activities is available at http://www.eso.org/public/events/astro-evt/deepimpact/media/di-news/.