SAAO - South African Astronomical Observatory

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Spectrograph Fibre Positioner

 

The Detector

The present detector is the SAAO TEK6 CCD camera, a Tektronix tex2html_wrap_inline525 chip with 24 tex2html_wrap_inline373 m pixels, which are well matched to the optical fibre size (the 50 tex2html_wrap_inline373 m fibre projects to 1.9 pixels). Although cosmetically poor (see section on flat fielding below), it seems well suited to ├ęchelle 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