LDSS (Low Dispersion Survey Spectrograph) is the AAT's
multi-slit spectrograph with a FOV of up to 12 arcminutes. In January of
1998 the LDSS++ project was inaugurated to provide the following enhancements:
The new CCD + VPH combination gives a factor of 2 performance
gain in the throughput at 7000A. For more infomation see the following:
A unique microslit mode permitting up to 300 objects to be
observed (factor of 10 increase in typical multiplex). Sky-subtraction
is achieved by the means of synchronised CCD charge-shuffling and telescope
A new red-optimised Volume Phase Holographic (VPH) grism
with 84% peak throughput.
A new MIT/LL deep depletion CCD with a peak 90% red QE.
A summary of LDSS++ instrument parameters and sensitivity
is available here. A general description of the
optical system is available in: Wynne & Worsick, The Observatory, 108,
161 (1988). As this journal can be a bit hard to find we have scanned it
in, with the journal's permission, and made
this article available as a gzipped
Postscript file (0.8 Mb).
January 1998 AAO Newsletter article describing the LDSS++
plans. (gzipped PS file, 0.4 Mb)
November 1998 AAO Newsletter article describing the commissioning
of LDSS++. (gzipped PS file, 1Mb).
LDSS Mask Design.
A software package is available
to do this, with documentation describing
the software and the process of mask design.
Karl Glazebrook Last change:
June 25th 1999.