Orbital determination of an asteroid (or any other body in the solar system) requires observations of its position in the sky at at least three separate times. For pedagogical reasons, SSP students use a combination of digital (CCD) and analog (film) observations. On the first full day of the program, students are organized into to teams of three and taught to select an appropriate asteroid to observe. By the third night, teams begin regular nighttime observing runs, accompanied by a teaching assistant. Students use both an astrograph -- telescope designed for sheet-film astrophotography -- and a CCD-equipped telescope.

Day 1: a team works on asteroid selection.

They guide the astrograph manually (using a paddle) through exposures ranging from 10 to 20 minutes, then develop the 4x5 inch sheets of film in a photographic darkroom. Digital images are much briefer, so manual guiding isn't necessary; the telescope and camera are controlled by The Sky 6 Professional and CCDSoft software (both generously donated by Software Bisque).

In Socorro the equipment is similar, but not identical: students use a Celestron C-14 reflector and SBIG CCD camera on a Paramount ME robotic mount. For analog observations, the telescope is a Takahashi FS-152mm fluorite apochromatic doublet refractor on a second Paramount.

Day 1: orientation on the Takahashi astrograph.

After taking an image, the team must locate the asteroid's dot of light among the background stars, then precisely measure its position relative to known reference stars (assisted by The Sky software). With film, they use precision machines called "measuring engines"; for digital images, they write software using the open-source language Visual Python. After converting the positions from three or more observations to celestial coordinates, the students' software calculates the asteroid's velocity and acceleration vectors using numerical differentiation, then transforms those values to the six orbital elements that describe the asteroid's orbit.

In summary, teams of three students perform every step themselves: choosing their asteroid, pointing the telescope, taking the images, measuring the asteroid's position, converting to celestial coordinates, calculating the orbit. Some students go on to improve the accuracy of their calculated orbits using additional observations to make differential corrections. Finally, Visual Python also allows them to make an animation of their asteroid orbiting the sun!

Each team's observations are submitted for archiving at the Minor Planet Center of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.