LDSS++ Information

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:

  1. 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 nodding.
  2. A new red-optimised Volume Phase Holographic (VPH) grism with 84% peak throughput.
  3. A new MIT/LL deep depletion CCD with a peak 90% red QE.
The new CCD + VPH combination gives a factor of 2 performance gain in the throughput at 7000A. For more infomation see the following:
  1. January 1998 AAO Newsletter article describing the LDSS++ plans. (gzipped PS file, 0.4 Mb)
  2. November 1998 AAO Newsletter article describing the commissioning of LDSS++. (gzipped PS file, 1Mb).
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).

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.