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IDS GENERAL INFORMATION
What is the IDS?
What are the resolutions available ?
Which CCD is normally in use, and what are it's specifications
?
What is the pixel scale in the spatial direction, and
what is the longest unvignetted slit length that I can use ?
What is the throughput of the instrument - how can I
calculate my exposure times ?
If the IDS is not suitable for me, what other possible
options are there available at ING ?
Information on the slit-viewing orientation on the TV,
and correspondance with chip geometry
Back to IDS Homepage
What is the IDS ?
It is a long-slit spectrograph which sits at the Cassegrain Focal station
of the 2.5m INT and is equipped with two cameras, called the 235mm and 500mm
Cameras. Their names merely denote their respective focal lengths. Presently,
only the 235 mm camera is offered.
What are the resolutions available ?
A wide range of gratings are available (16 in all). Possible grating combinations
with the 235mm camera and the EEV10 detector allow dispersions of between
0.24 and 3.7 Å per pixel. This corresponds to spectral resolutions
ranging from 0.5 Å to 7.5 Å FWHM (corresponding to two
pixels FWHM on the detector).
Which CCD is normally in use, and what are it's specifications ?
IDS is presently offered only with offered in combination with the EEV10 detector. (Click here for characteristics
of the 4kx2k thinned EEV42-80 chip).
What is the pixel scale in the spatial direction, and what is the longest
unvignetted slit length that I can use ?
With the 235 mm camera and the EEV10 CCD, the spatial scale along the slit
is 0.4 arcsec per pixel. With the dekker in the clear position, the longest
slit length employable before vignetting occurs is ~4 arcmin.
What is the throughput of the instrument - how can I calculate my
exposure times ?
The SIGNAL
program contains updated measurements of the IDS throuhgput, with an accuracy
of some 20%. You can then safely use it to estiamte your exposure
times.
If the IDS is not suitable for me, what other possible options are there
available at ING ?
An intermediate dispersion spectrograph, ISIS with a double-arm facility
(allowing simultaneous red and blue light observations) is available on the
4.2m WHT and provides similar spectral resolution to the IDS and is more
efficient (on the top of the larger mirror diameter of the WHT).
Information on the slit-viewing orientation on the TV, and correspondance
with chip geometry
Some observers may want to work out the direction that the slit was pointing,
and which end of the slit corresponds to which direction spatially on the
particular CCDS. Here you have some help:
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Last Updated: 15 February 2006
Romano Corradi, rcorradi@ing.iac.es
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