T11 0.80 meter APT

Observing Program

The T11 0.80m APT became operational in the Fall of 2000 at Fairborn Observatory. T11 is a functional duplicate of the T8 APT, including the two-channel photometer on the standard Stromgren b & y system. Funding for the construction and operation of the telescope has come from NASA, NSF, and Tennessee State University.

T11 is dedicated to long-term monitoring of solar-type stars in a program that extends the work of T4 and T8. The data are used to follow long-term luminosity cycles in these stars that are associated with their magnetic cycles as well as to characterize shorter-term brightness variations that will help interpret the results of planetary search programs. The telescope is also used to search for planetary transits in promising candidates.


  • 31.5-inch Cassegrain optics of sitall by Star Instruments
  • Primary focal ratio is f/2; effective focal ratio f/8
  • Horseshoe equatorial mount with quadrapod secondary mirror support by Fairborn Observatory
  • Disk and roller drive systems on both axes
  • High-precision, two-channel photometer with dichroic beam splitter from Fairborn Observatory
  • Stromgren by filters
  • Neutral density filters with attenuation of approximately 1.25, 2.5, 3.75, and 5.0 mag.
  • Selectable diaphragm wheel with diameters of 30, 45, 60, & 90 arcseconds
  • Two EMI 9124QB photomultipliers
  • PMTs, voltage divider, preamp, and filters in sealed, environmentally-controlled chamber
  • ATIS93 control system from Fairborn Observatory
  • Construction Photos