Lowell Observatory (Flagstaff, AZ) and the University of Arizona’s College of Optical Sciences (OSC; Tucson, AZ) finalized a $3 million, three-year contract last month to complete the 4.3-meter-diameter, 6700 lb Discovery Channel Telescope (DCT) primary mirror. The DCT is a joint project of Lowell Observatory and Discovery Communications (Silver Spring, MD). Upon delivery of the mirror to OSC, scheduled for last month, an engineering team, led by OSC’s principal investigator on the project, Martin Valente, will take more than six months to bond a minimum of 120 pucks to the mirror’s convex backside, creating a support structure to hold the mirror just as it will be held in the telescope. This will keep the mirror from flexing under the force of grinding and polishing, which will take another five months.
The final stage of polishing, to make the mirror accurate to within a fraction of a wavelength of light, is expected to take another 15 to 18 months. Optical sciences students, under the supervision of project co-investigator Jim Burge, will also design lenses to independently test the mirror using test systems that will include a laser tracker and infrared and visible wavelength interferometers. Contact Martin Valente at [email protected].