Status of the Observations

3.1. Summary of the Observing Runs

To date, we and our collaborators have obtained optical imaging data on 250 nights using 13 telescopes at 9 ground-based observatories world-wide in order to characterize the nucleus rotation state, size, albedo and dust development, in addition to data from the Keck 10 m and Spitzer telescope for albedo and nucleus size measurement and the Hubble Space Telescope for rotation determination. The level of cooperation among planetary colleagues as well as from colleagues outside the field has been excellent. In additional to our formal collaborators, there have been many observers who have given up some large telescope time in order to help out the mission, and they have made a tremendous contribution to our understanding of the nucleus properties. A summary of these runs through 2004 is included in Table V.

3.2. Development of the DI Database

In order to facilitate access to the growing amount of Deep Impact ground-based imaging, we designed and developed a relational database using IBM's DB2 database management system, which can be queried using a web interface developed in ColdFusion MX.

In its current form, the database contains reduced data products (photometry) from the ground-based CCD imaging program. Routines developed in perl are used to parse the text files containing reduced data and insert the data into the database. Full information about the observations obtained on each night, including information about the observers and observing conditions, seeing, the instrument and telescope used (along with filter transmission curves and CCD quantum efficiencies) are stored in the database. Each observation is also tagged with the instantaneous values of the heliocentric and geocentric distances (r and A) and phase angle (a), as well as the sun-centered and Earth-centered state vectors. These values are obtained automatically by communicating with the Jet Propulsion Laboratory Solar System Dynamics ephemeris routines when new data is uploaded to the database.

This Deep Impact database can be queried using a password protected web interface (see Figure 4). The returned data can be sorted on several key parameters, such as date, time, filter, photometry aperture, by telescope, observer or instrument, and returned as either an HTML table, tab-delimited dataset, an excel spreadsheet or CSv file format.

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