Telescope Properties

The Robotically-Controlled Telescope (RCT) is a 1.3-meter (50inch) f/14 Cassegrain telescope on a German equatorial mount. Located on Kitt Peak in southern Arizona at an elevation of 2070 meters (6790 feet), the RCT occupies the dome across from the Kitt Peak Visitors’ Center and adjacent to the KPNO administration building. The RCT name originally stood for Remotely-Controlled Telescope, and it served the KPNO user community almost 30 years before being closed in 1995 (read more on the RCT history page).

Kitt Peak and the RCT Telescope

The RCT site highlighted on an image of Kitt Peak National Observatory. The long building attached to the RCT dome is the Kitt Peak administration building. Image Copyright Association of Universities for Research in Astronomy Inc. (AURA), all rights reserved. Inset modification by G. A. Esquerdo.

The RCT Consortium operates the telescope with a CCD camera employing a 2048×2048 pixel SITe CCD (24 micron pixels for a plate scale of 0.3 arcsec/pixel and 9.6×9.6 arcmin field of view). This camera is cooled using a Polycold (cryogenic) compressor and closed circuit of supply and return lines, allowing the camera to operate for extended periods without maintenance. The CCD controller electronics were built by Bob Leach and allow a variety of operating modes (e.g., readouts through a combination of up to 4 amplifiers, windowing, on-chip binning). Two filter wheels are available at all times on the telescope and hold up to 16 broadband and narrowband filters.

 The telescope can be operated in different observing modes. In automatic mode, the telescope  opens automatically and executes a series of observations, deciding which objects to observe based on a list of pre-established scheduling priorities and observing conditions. A weather station next to the dome monitors the conditions to ensure the telescope’s safety. The RCT can also be controlled remotely via the internet, executing tasks in real time for an observer located anywhere in the world. Finally, an on-site observer can control the telescope’s functions from a warm room located inside the dome.

Besides a computer network for camera and observatory control, computers in the dome archive the data automatically after each night’s observations.

The RCT filter set currently contains the UBVRI broadband filter set, a red continuum filter (6444Å) and narrowband filters for H alpha (6563Å) and CN (3870Å) in filter wheel 1. Filter wheel 2 contains filters for NH2 (5721Å) and continuum (5660Å), C2 (5141Å) and green continuum (5260Å), C3 (4062Å) and blue continuum (4450Å), together with narrowband filters for SII (6717Å) and OIII (5007Å). The CN, NH2, C2 and C3 filters are intended for observations of comets. A third filter wheel currently holds filters for He II (4689Å), H beta, , NII (5759Å & 6585Å), and SII (6731Å) .  Other filters available include OH (3090Å) and UV continuum.