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INGRID: Instrument Overview


  1. INGRID - A near-infrared imager
  2. INGRID and the Adaptive Optics Suite
  3. Applying to use INGRID
  4. Recent Developments

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INGRID - A near-infrared imager


INGRID forms an integral part of the ING's adaptive optics suite NAOMI. Since early 2004 it has been permanently attached to one of NAOMI's two science ports in the environmentally controlled enclosure GRACE at the WHT's Nasmyth focus. The 1024x1024 HgCdTe Hawaii detector array has a pixel scale of 0.04"/pixel, with a resulting field of view of approximately 40" x 40", and a wavelength range from 0.8 to 2.5 µm. More information on the detector can be found here. INGRID's two filter wheels contain a range of broad and narrow band filters and a further wheel holds a selection of pupil stops. The diagram below shows a 3D transparent model of INGRID, with the light beam from the telescope focusing on the infrared detector.

Picture credit: Paul Jolley (ING)

INGRID was mostly built and developed at the ING and was commissioned in March 2000. It was originally deployed at both the Cassegrain and Nasmyth focal stations to provide (i) a wide field imaging capability over a ~4´x4´ field of view and (ii) a high resolution imaging mode over a ~40"x40" field of view (with the AO system NAOMI). However, following the successful commissioning of LIRIS in 2003/2004, INGRID's wide field functionality at Cassegrain has been replaced by LIRIS's imaging mode, meaning that INGRID is now one of two dedicated science instruments for NAOMI. In early 2004, INGRID underwent a major reengineering program to improve its mechanism control system, thus enhancing both the reliability and accuracy of its filter and pupil wheels.

INGRID and the Adaptive Optics Suite


INGRID is mounted on the adaptive optics bench in the GRACE enclosure. The light path from the telescope always passes through the adaptive optics system before reaching INGRID. Two keys optical elements in the light path are (a) a tip tilt mirror and (b) a 76 element segmented deformable mirror (DM). INGRID can be operated with NAOMI in three modes:
The next section gives an overview of how to apply for INGRID observations. INGRID can also be used with the ING's AO coronograph OSCA - more details on the specific preparation needed for OSCA observations can be found here.

Applying to use INGRID


If you are interested in using INGRID you should read the planning observations page, which discusses the requirements for performing AO observations, and the latest NAOMI/INGRID performance summary. To assist you with your planning we also provide a S/N calculator. You can apply for INGRID in both scheduled and service mode - you can read more about these modes and how to apply here.

Recent Developments


An exciting recent development at the ING is the implementation of a Rayleigh laser guide star system GLAS, which was commissioned in 2007. This opens up virtually the whole sky for AO observations with INGRID (and with the optical integral field spectrograph OASIS). Laser-assisted AO still requires a natural guide star in the neighbourhood of the target to perform tip-tilt correction; this guide star should be brighter than V=17, and for optimal performance should be located within 1 arcmin of the target.

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Last Updated: 30 January 2008
Ian Skillen, wji@ing.iac.es