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OSU College of Arts and Sciences Department of Astronomy


A Retractable Optical Camera for the MDM 2.4m Hiltner Telescope

Three-color image of NGC 7714/15 (RETROCAM: 2004 Aug 25)


RETROCAM, the RETRactable Optical CAmera for Monitoring, is mounted on the side port of the Multiple Instrument System (MIS) at the f/7.5 Cassegrain focus of the MDM 2.4m Hiltner Telescope. It employs a retractable pick-off mirror that can be inserted into the telescope beam in front of the primary instrument. Because of its location in the MIS, it is available for use with any of the observatory's primary instruments except for the 8K imager, which does not use the MIS.

A detailed description of RETROCAM can be found in this paper:

"RETROCAM: A Versatile Optical Imager for Synoptic Studies", Morgan, C.W. et al., 2005, AJ, 129, 2504 (632k PDF)

User's Guide

A "quick-reference style" set of instructions for RETROCAM:
RETROCAM User's Guide (141k PDF)
Version 2.1 - updated 2007 Sept 24

RETROCAM v2 has updated features, including a working TCS interface (including remote focus, mirror, and guide probe x,y position setting), and a simple scripting facility described by the document below.

RETROCAM Command Scripts (607k PDF)
Updated: 2006 Dec 18 (new commands)


Camera: Apogee ALTA E55
CCD: E2V CCD 55-20 (1152x770 22.5um pixels)
Dark Current: 2.5 e/sec/pixel at -20°C
Gain: 3.0 e-/ADU
Pixel Scale: 0.259 arcsec/pixel
Readout noise: 13.4 e/pixel
Readout time: 6 seconds
Cooling: 3 stage thermoelectric (-20°C below ambient)
Field of View: 4.97 x 3.32 arcmin
Filters: SDSS g, r, i and z + 1 open position


RETROCAM was designed and built by Chris Morgan to monitor gravitationally lensed quasars. That project is ongoing.

Observing instructions for the quasar monitoring project:

RETROCAM Lensed Quasar Observing Instructions (95k PDF)