GRACE

The new AO controlled environment on the WHT for NAOMI/OASIS, GRACE (GRound-based Adaptive optics Controlled Environment) is a project to set up at the WHT Nasmyth 2 platform, currently occupied by the Utrecht Echelle Spectrograph (UES), a dedicated structure designed to facilitate the routine use of AO using ING's planned instrument suite (NAOMI/OSCA/INGRID/OASIS).

The design of GRACE allows for the future deployment of laser guide stars. The core of the project is to remove UES from the WHT Nasmyth 2 platform and construct a building to enclose the instrumentation and electronics. The building will be similar to GHRIL (Ground-based High Resolution Imaging Laboratory) on the WHT's Nasymth 1 platform but optimised for its contents. The building will be sealed to the telescope and have a suitably controlled environment for AO.

Gains from the project include:

• AO suite fixed in place facilitating service observing matched to seeing.
• No physical instrument changes needed, except for INGRID.
• Controlled environment for AO.

GRACE will be a prefabricated or modular building with internal partitions for electronics, and a seal on the optical path. Access for major items NAOMI, OASIS etc is from the overhead crane via hinged doors in the roof. For smaller and lighter units there is a double door, with a single personnel door large enough to take a liquid nitrogen dewer.

Services needed GRACE will provide the following services to the AO suite:

• Electricity 220v 50Hz Single Phase, neutral and earth
• Cooling by water/glycol circuit - electronics rooms controlled temperature
• AO instrument area controlled to track dome temperature with environmental monitoring/control system.
• Water glycol circuit directly connected to cooling circuits of equipment in the AO instrument area
• Instrument air 7 bar gauge dry air, for pneumatic operation of mechanisms and detector window anti-condensation flow
• Liquid nitrogen for detector cooling supplied from mobile dewer, oxygen alarm for personnel protection
• Lighting
• Computer network
• Helium lines for the INGRID closed cycle cooler
• Telephone

The programme for GRACE is:

1. PROJECT LAUNCH 1-Jul-2001
2. BUILDING DESIGN COMPLETE 31-Aug-2001 30-Sep-2001
3. BUILDING DELIVERED AND INVOICED 31-Mar-2002
4. FLOOR AND SYSTEMS DESIGN COMPLETE 30-Apr-2002
5. FLOOR AND SYSTEMS MATERIAL ORDERED 31-May-2002
6. FLOOR AND SYSTEMS MATERIAL DELIVERED 31-Jul-2002
7. LAST AVAILABLE DATE FOR UES 31-Jul-2002
8. UES REMOVED AND PLATFORM CLEARED 31-Aug-2002
9. ASSEMBLE BUILDING AND TEST SYSTEMS 31-Oct-2002
10. INSTALL NAOMI 30-Nov-2002 INSTALL OASIS 31-Dec-2002