FIERA CCD Tests

During October and November of 2003, the FEROS CCD Controller was changed from the original Copenhagen University Astronomical Observatory BIAS CCD Controller to an ESO-VLT Compliant FIERA controller. Historical CCD performance information for the BIAS system can be found here. The FIERA controller is capable of delivering the full performance of the CCD in terms of readout noise, CTE, immunity from interference, crosstalk, etc., and provides the image files with the necessary header information.
Five standard readout modes are available (the Conversion Factor (CF), ReadOut Noise (RON) and ReadOut Time (ROT) figures given below in table 1 are representative)

CCD Characteristics
ReadOut Mode CF [e-/ADU] RON [e-] ROT [s] Dark Curr [e-/pix/hr] CTE [par/ser] Linearity [%] Full Well Cap. [e-] Num Ports Purpose
225kHz,1,low,1x1 (norm) 2.96 4.80 41 1.1 TBD TBD 150,000 1 For High S/N Observations
60kHz,1,high,1x1 (slow) 1.03 2.67 148 1.1 TBD TBD 150,000 1 For faint, RON-limited sources
625kHz,1,med,1x1 (fast) 2.56 6.48 21 1.1 TBD TBD 150,000 1 For fast-monitoring observations
225kHz,1,low,2x2 (norm 2x2 binning) TBD TBD TBD TBD TBD TBD 150,000 1 For High S/N Observations
60kHz,1,high,2x2 (slow 2x2 binning) TBD TBD TBD TBD TBD TBD 150,000 1 For faint, RON-limited sources
Table 1

The performance figures given in table 1 were updated on 2004-12-05. They were derived from the regular CCD tests carried out in during the period Nov-2003 -- Dec-2004.

Note: the 625kHz,1,med readout mode should be considered EXPERIMENTAL and should not be used for science data until it has been properly commissioned which will not happen unless there is a well defined and strong scientific case for doing so. It is definitely NOT offered in Service Mode. Visitor's wishing to use this readout mode must contact the FEROS instrument Scientist well in advance of preparing their Phase 1 proposal.

Regular CCD Tests in the three 1x1 binning readout modes began in Nov 2003. They are carried out on a daily to weekly basis using the remote controlled Stabilized LED sources permanently mounted inside the spectrograph on a ring just in front of the camera, and on a two to three times a year basis using a standard Beta-Light source since to use the Beta-Light we must enter the FEROS Climate Controlled Room which we try to do as infrequently as possible in order to maintain the temperature stability of the instrument.

Regular CCD Tests in the 2x2 binning readout modes have not yet been started. Due to time constraints it is no longer possible to check all LEDs in all readout modes, while still all readouts are checked at least on a weekly base.

Source
norm 1x1 binning
slow 1x1 binning
fast 1x1 binning
norm 2x2 binning
slow 2x2 binning
Beta light
225kHz,1,low,1x1
(discontinued)
60kHz,1,high,1x1
(discontinued)
625kHz,1,med,1x1
(discontinued)
N/A N/A
Red LEDs
225kHz,1,low,1x1 60kHz,1,high,1x1
(discontinued)
625kHz,1,med,1x1
(discontinued)
N/A N/A
Green LEDs
225kHz,1,low,1x1 60kHz,1,high,1x1 625kHz,1,med,1x1 N/A N/A
Blue LEDs
225kHz,1,low,1x1 60kHz,1,high,1x1
(discontinued)
625kHz,1,med,1x1
(discontinued)
N/A N/A