The optics of the 30-inch telescope is based on the design of the Cassegrain telescope. It consists of a parabolic primary mirror which focuses incoming parallel rays onto a hyperbolic secondary mirror which then reflects and focuses light back down through a hole in the primary mirror. Behind this hole lies the infrared array detector that we will use.
The infrared camera is sensitive to wavelengths between 0.9 to 2.5 m. The camera is equipped with 3 different filters on a cold filter wheel to isolate specific astronomic bands of wavelength. The filters are in the J-band (1.25 m), H-band (1.65 m) and the K-band (2.2 m). Since we are detecting light at infrared wavelengths, temperature control is essential. The filters are kept cold so as to reduce the thermal noise contribution from the filters to the camera. In addition, the camera itself is kept cold using a closed cycle helium refrigerator.