Three CCD read-out (R/O) speeds are possible: normal
(normal,100kps), fast (fast,225kps), and very fast
(vfast,625kps). The only binning modes offered are 1x1 and 4x1, i.e.
no binning in the dispersion direction is offered.
Note that "X" is the
direction perpendicular and "Y" is the direction parallel
to the dispersion (in the CCD image "lambda goes up").
Recommended R/O spead for scientific exposures is
normal. Programmes which require minimum overhead times
(i.e. R/O time, data transfer, and
storage) should use fast R/O. CCD binning also reduces
the overheads. vfast R/O is not recommended for scientific
applications.
The following table lists the temporal overheads for the various
R/O speed and binning modes. They are precise to ±1 sec.
|
CCD modes and read-out/transfer time |
|
| Binning XxY |
Normal R/O |
Fast R/O |
Very fast R/O |
| |
|
|
| 1x1 |
51 sec |
26 sec |
15 sec |
| 4x1 |
16 sec |
11 sec |
7 sec |
|
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