The Detector

The present detector is the SAAO TEK6 CCD camera, a Tektronix chip with 24 m pixels, which are well matched to the optical fibre size (the 50 m fibre projects to 1.9 pixels). Although cosmetically poor (see section on flat fielding below), it seems well suited to échelle spectroscopy. The chip has two read out amplifiers, which operate in parallel. Measurements done in the SAAO electronics lab (December 1997) gave the following chip characteristics:

Top half: Gain = 0.833 ADU/electron
Readout noise = 6.7 electrons
Bottom half: Gain = 0.926 ADU/electron
Readout noise = 6.1 electrons