Principal Components

The RCT CCD

is a grade 0 (highest quality) 2048x2048 pixel SITe424 backside-illuminated CCD with 24 micron pixels. On the RCT Cassegrain focus, this produces pixel scale of 0.29 arcsec/pixel and a square field-of-view 9.9 arcminutes on each side.

The dewar

was manufactured by Infrared Laboratories (1808 E. 17th Street, Tucson AZ, 520-622-7074), designed specifically for use with the closed cycle (Cryotiger) cooling system, having the cold end of this cooling system imbedded and in contact with the CCD.

The CCD electronics

are located both inside the dewar and in a separate (warm) box mounted on the side of the dewar.

The shutter

is an iris that is held open when an electric current is applied. The shutter is mounted between the dewar and the filter mechanism.

The filters

are 114.8 mm diameter circles, mounted in a pair of filter wheels, each with 9 positions (one left open). A third wheel is available and can be swapped with one on the telescope. The filter wheels reside in the same box as the guide camera.

A dual-boot PC

runs the CCD camera. Software called Voodoo, which is supplied by the camera manufacturer, Astronomical Research Cameras, Inc. We currently operate Voodoo under Windows, but it can also operate under Linux. Communication between the instrument computer and the camera is made through a pair of optical cables which attach to a PCI card on the PC.

The Cryotiger cooler

is a closed circuit system consisting of a compressor on one end and condensing "cold tip" unit on the other. The model is the Cryotiger, originally supplied to the RCT by APD Cryogenics whose Cryotiger line has since been bought by IGC-Polycold Inc. The two ends are connected by a pair of flexible metal hoses representing supply (running towards the camera) and return. The compressor sits in the control room under the table and the cold tip is mounted inside the dewar. The cooling system is entirely independent of the camera and observatory software. When powered on, it cools down to approximately -110C or so depending on the load. The camera software can run a thermostatic heater to raise and maintain a constant temperature above what the cooler provides.