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1 System Overview

The Gold Camera is the CCD spectrometer for long slit or stellar spectroscopy (1-15Å resolution) on the Gold spectrograph at the KPNO 2.1-meter telescope.

The camera itself is a semi-solid f/1.25, 190mm focal length three-component meniscus type. The slit demagnification factor is 4.3, producing a spatial scale of 0.78 arc-seconds/pixel on the chip. A description of the basic design ("E") by Wynne can be found in MNRAS, 157, 403,1972. Several modifications to this camera permit the use of a CCD. The last element of the camera has been replaced with a combination field flattener and dewar window. To optimize the performance at 3800Å, a new front meniscus lens was also constructed. This system has been designed to hold CCDs up to two inches square (with the capability to mount the chip off-center if only parts of the chip are good). The CCD is permanently mounted behind the camera (like the KPNO Cryogenic Camera and the CTIO Air Schmidt).

The CCD detector, labeled F3KC, was installed in the GoldCam in February 1992. It is a Ford chip with 3072 columns and 1024 rows. The pixel size is 15 microns making the physical length of the chip 45 millimeters. This is a good match for the spectrograph optics which were originally designed to feed a 40mm image tube. The chip is oriented such that the red end of the spectrum falls at low pixel numbers. Spatial scale on the chip is 0.78 arc-seconds/pixel. The entire five arc-minute slit length is usable with a slit demagnification of 4.3. Due to the camera design, the central 1.3 arc-minutes are unvignetted, but response falls off linearly to about 75% at either edge (25% vignetting). The plate scale of the 2.1-meter telescope is 12.7 arcsec/mm (79/arcsec). Figure 1 is an optical view of the spectrograph.

CCD data observations are taken with a SPARC 10-30 workstation called LAPIS. Lapis uses the IRAF Control Environment (ICE) for data acquisition, reduction and display of the data. Open Windows is the interface to the observer. The user also has access to several other functions, such as SNAPSHOT, MOSAIC, and WEATHER. Lapis has 5 GB of disk storage. In additional there are tape facilities for Exabyte, DAT, and nine-track.

Software exists within IRAF to reduce GOLDCAM data. Available documentation includes: A User's Guide to Reducing Slit Spectra with IRAF and Guide to the Slit Reduction Task DOSLIT. Other documents that will be found useful are User's Guide to CCDRED and Phil Massey's A User's Guide to CCD Reductions With IRAF. Although it is somewhat out of date the cookbook Reduction of Longslit Spectroscopic Data Using IRAF may be of some use. These manuals may be found in the IRAF Documentation Room downtown or can be viewed via MOSAIC..