Deep Impact Mission to 9P/Tempel 1

Comet 9P/Tempel 1 is the target of a NASA mission called Deep Impact. The objective of this mission is to send a flyby spacecraft to comet Tempel 1 in 2004. During the summer of 2005, the spacecraft will launch an 500-kg impactor towards the nucleus of the comet. The goal is to excavate a crater about 20-m deep. The resulting impact will be observed by the spacecraft and by ground-based observatories.

The mission is currently in the design stage. We need to develop computer models of the comet to aid mission design. However, comet Tempel 1 has not been heavily studied in the past! We need to gather scientific data about the comet's brightness changes, coma structures, and dust activity. We need coverage of the comet over several days as well as several months. This is difficult, if not impossible to do at professional observatories. To meet this need for data, we have established the Small Telescope Science Program, a network of professional and technically advanced amateur astronomers from around the world to make CCD observation of the comet from now through December 2000.

We can extract valuable, scientific information from high-quality, ground-based, CCD images taken with standard photometric "V" and "R" filters (used heavily in research) or with common "RGB" filters with an infrared-cutoff filter. Also, images taken with no filter or a clear filter will allow us to calculate coma brightness changes over time and heliocentric distance. Here is a summary of the observing requirements for our science program:

1) Take 3-5 flat fields for each filter.  
2) If your CCD software does not automatically subtract a dark frame
   from each image, take at 3-5 separate dark frames with exposure
   times to saturate pixels to about 1/5 of the maximum pixel value.
3) Take multiple, short exposures of the comet.  If your CCD software
   allows you to set tracking rates, you may track a the comet's
   rates (right ascension and declination or altitude and azimuth) and
   take longer exposures.
4) Keep an observing log.
5) Transmit all images in FITS format.  We need raw, unprocessed images
   so we can perform detailed image analysis! You are welcome to process
   your images and to estimate magnitudes and relay is information to us
   as well.  
We will post your images on the web, and we WILL acknowledge you if we publish scientific articles based on your data!

Information about the Deep Impact Mission

We have a website for the Small Telescope Science Program. The site provides detailed observing requirement as well as CCD images taken by some of our program's observers.

The comet currently has an apparent visual magnitude of about 15 (possibly as faint as 17) and is visible in the early morning from both the southern and northern hemispheres. The comet passed perihelion in January 2000 and is rapidly receding from us. After December 2000, the comet will be too faint to observe. The next time to observe it will be be until 2004!

Stef McLaughlin

Stephanie McLaughlin                Phone:  301-405-1566 
Department of Astronomy             Fax:    301-314-9067 
University of Maryland              Email:
College Park, MD 20742-2421 USA