The Intermediate Dispersion Spectrograph (IDS) is a long-slit spectrograph
which sits at the Cassegrain Focal station of the
2.5m Isaac Newton Telescope and is
equipped with two cameras, called the 235mm and 500mm Cameras
according to their respective focal lengths.
Starting from semester 06B, IDS is offered with the whole
set of gratings (16), but only with the 235 mm camera and the EEV10
CCD. Possible grating combinations with this configuration
allow dispersions of between 0.24 and 3.7 Å per pixel. The spatial
scale along the slit is 0.4 arcsec per pixel. The full unvignetted slit length
is 3.3 arcmin.
Starting from semester 11A, IDS is offered with a new CCD more
sensitive in the red, namely RED+2, with the full set of gratings (16) and the
235 mm camera. The spatial scale along the slit is 0.44 arcsec per pixel.
Possible grating combinations with this configuration allow dispersions
in a very similar range with the EEV10 CCD and a similar full unvignetted
slit length.
The
SIGNAL program
(S/N calculator) contains reliable updated measurements of the IDS throuhgput
with the two cameras, with an accuracy of some 20%. You can then safely use
it to estimate your exposure times.
Note that IDS will be scheduled in minimum blocks of 4 weeks, as
the ING can only support a small number of instrument changes each
semester. For this reason, we invite the community to present large
programmes to make the best use of the INT (smaller proposals asking no
less than 4 nights are still accepted). IMPORTANT: in
case a long run is going to be covered by several observers, please let us
know well in advance so that student support can be scheduled each time a
new team goes up.
