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NOAO Annual Report FY 1999


NOAO Instrumentation

The mission of the Instrument Projects Group (IPG) is to develop and produce major instruments for the NOAO nighttime telescopes, including KPNO, CTIO, and Gemini. The NOAO scientific staff conceives, directs, prioritizes, and evaluates instrumentation projects; the engineering managers are responsible for meeting schedule, budget, and performance requirements. NOAO astronomers initiate new instrument projects in response to user requests, scientific staff interests, advances in technology, and announcements of opportunity from the International Gemini Project.

Managing the instrumentation resources efficiently and in a manner satisfactory to all sites is crucial to the success of our program. The Instrument Projects Advisory Committee (IPAC) provides scientific prioritization to the IPG. Its FY 1999 members were Taft Armandroff (NOAO-Opt. Instr.), Sam Barden (KPNO), Dave De Young (Secretary), Buell Jannuzi (USGP), Dick Joyce (KPNO), Mike Merrill (NOAO-IR Instr.), Ron Probst (CTIO), Alistair Walker (CTIO), and Sidney Wolff (NOAO-Chair). IPAC meets with the instrumentation engineering managers about once a month to review priorities, schedules, and budgets. They develop the scientific content of the long-range plan, on the basis of input from the users through the Users’ Committee and personal contact, from the WIYN and SOAR partners, and from the Gemini advisory structure through the USGP. Every instrument under development has an instrument scientist from the NOAO scientific staff. We believe that this arrangement is essential for successful development; each instrument must have a champion to see that the project meets its scientific performance goals. IPAC provides a venue where the interests of each site are fairly represented.

During FY 1999, our ongoing projects advanced, as described below.

CCD Mosaic Imager

In FY 1999, the cloning of the CCD Mosaic Imager for CTIO was completed. IPG has now produced two imagers with 8192 x 8192 format and an active imaging area of over 12-cm on a side. It has a large filter transport mechanism holding 14 six-inch filters and a pneumatically controlled shutter mechanism that gives 1% timing accuracy in one-second exposures. The CCD controller is a multiplexed quadruple version of the ARCON, developed and produced at CTIO. The CCD Mosaic at KPNO has been in use with thinned, scientific grade CCDs since August 1998. The second Mosaic, for CTIO, was completed, on schedule, in FY 1999. Deployment and commissioning at the Blanco prime focus occurred in July 1999. The CTIO Mosaic was used successfully for several visitor science projects during August and September 1999 and is heavily scheduled for Semester 1999B.

WIYN MiniMosaic

Using the same type of CCDs as Mosaic and nearly identical software, a MiniMosaic CCD Imager was constructed for the WIYN 3.5-m telescope during FY 1999. The new imager is a pair of thinned, back-side illuminated, anti-reflection coated 2048 x 4096 SITe devices, arranged to mimic a 4096 x 4096 array. Each 15 m pixel corresponds to 0.141 arcsec, yielding a field size of 9.6 x 9.6 arcmin. The two CCDs are read out through a total of four amplifiers using a HArcon controller. The instrument was commissioned during FY 1999, and is expected to be released for general use in November 1999.

Phoenix

Phoenix is a high-resolution near-infrared spectrograph operating from 1--5 m using two quadrants of an ALADDIN InSb array detector. The instrument received a number of upgrades during FY 1999, including enhancements to the motor control of mechanisms and improvements to the collimator mounting and alignment. The latter improvement resulted in increased performance, particularly in the areas of spectral resolution and throughput, with Phoenix now meeting its original design goals. Negotiations are underway with Gemini and SOAR about the possible use of Phoenix on Gemini South and SOAR. Pending the outcome of these discussions, additional work will be required to facilitate Phoenix's use on Gemini and SOAR.

Hydra for CTIO

A new version of the Hydra multi-fiber positioner has been constructed and deployed at the CTIO Blanco 4-m telescope. In the area of wide-field multi-fiber spectroscopy, the existing 4-m telescopes complement the capabilities of the Gemini telescopes. Hydra-CTIO was built in Tucson, and is based largely on the design of Hydra as it was converted from use at the Mayall 4-m to use at the WIYN 3.5-m. New motor controllers, a new gripper, and new fiber cables were produced for the CTIO system, along with a new wide-field corrector with atmospheric dispersion compensating prisms. This instrument is located at the f/8 Ritchey-Chrétien focus and feeds a bench-mounted spectrograph. First commissioning activities occurred in October 1998, as per the original instrument schedule. The first visiting observers began using the new instrument in March 1999.

SQIID Upgrade

A high priority for users, as expressed through the Users' Committee, is wide-field near-IR imaging. The first realization of that capability will be in the upgrade of SQIID, the four-color near-IR imager. The 256 x 256 PtSi arrays will be upgraded to 512 square InSb arrays with a customized NOAO Wildfire Controller. That instrument should be available for commissioning observations on Kitt Peak in January 2000, now that an adequate number of InSb arrays is available. The primary effort on this project during FY 1999 was mechanical fabrication and electronics assembly of new multiplexing circuits to allow the incorporation of the new, larger arrays. Delays with respect to the previous schedule were induced by the extra efforts required on Phoenix and the GNIRS.

Gemini IR Array Controllers

The first facility instrument for the first Gemini telescope is the Near-Infrared Imager (NIRI), under development at the University of Hawaii. NOAO has produced for NIRI a powerful array controller that has very low noise. That system passed its acceptance review and was delivered to Hawaii in FY 1998. The NOAO design will serve as the basis for controlling the arrays in the other near-infrared instruments that will be used on Gemini, some of which will be provided by NOAO. During FY 1999, NOAO supported the integration of the array controller and NIRI.

Gemini Near-IR Spectrograph

The major instrument under production for Gemini is the Near-IR Spectrograph (GNIRS). This project is the largest instrument ever undertaken by NOAO. It will provide long-slit capabilities with a range of dispersions through selectable gratings, covering the wavelength region from 0.9 m to 5.5 m at two pixel scales by means of four interchangeable cameras, which feed a single 1024 square ALADDIN-type InSb detector. An internal review revealed that the effort required to complete the instrument to specification would considerably exceed the estimates presented at CDR. There were substantial problems with the original mechanical design, and consequently the instrument has been repackaged. The optical, electronics, and software designs were sound and were retained. The GNIRS project successfully passed an external restart review in July 1999. Current project schedules predict delivery to Gemini in July 2002.

GMOS/HROS CCDs

NOAO is providing the integration of CCDs, CCD Controllers, and relevant software for Gemini's GMOS and HROS optical spectrographs. The CCDs are from EEV in the UK, and the controllers are SDSU-2. Final integration and testing of the GMOS North CCD system were completed during FY 1999. The acceptance review for the CCDs and hardware was passed successfully in August 1999. Acceptance tests for the software for GMOS North are to be done in November 1999.

WIYN Tip/Tilt Imager

The WIYN 3.5-m telescope is the facility of choice on Kitt Peak for high-resolution optical imaging. In an effort to enhance our capabilities for high-resolution imaging over a moderate field, a tip/tilt imager is being constructed for WIYN. The WIYN Tip-Tilt Module (WTTM) is an optical/near-IR reimaging system that utilizes fast tip-tilt compensation and includes real-time focus sensing. The WTTM field of view is 4 x 4 arcmin at a plate scale of 0.12 arcsec per pixel. The WTTM will be attached to the WIYN Instrument Adapter System, which will facilitate quickly changing between the WTTM and the MiniMosaic Imager by simply moving a pick-off mirror (in response to changing atmospheric conditions, for example). The WTTM Preliminary Design Review was passed successfully in March 1999. Final design, detailing, and fabrication will occur during FY 2000.

Next-Generation Optical Spectrograph

Long-term studies are currently underway to define a next-generation multi-object moderate-resolution spectrograph for the 4-m telescopes. The following science goals have been formulated: 1) wide field of view (diameter of 20 to 40 arcmin) in order to complement the narrower fields of most 8-m telescope spectrographs; 2) multi-slit mask mode of operation; 3) typical resolving power of 5000 and possibly higher; 4) instrument to work within the window from 370 nm to 1.7 m with optical and IR detector packages; 5) peak efficiency for telescope, spectrograph, gratings, and detector of greater than 40%. This last goal is made possible by advances in holographic volume phase grating technology, and also coating technology. Conceptual optical designs are under development.


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