1. Introduction

The Gemini observatory is poised to play a key role in the great scientific investigations of the 21st century. These future scientific explorations will be exciting to both the astronomical community and the general public; including the search for other planetary systems, the formation and evolution of galaxies, and the understanding of star formation. Gemini is in this favorable position because the Gemini telescopes on Mauna Kea in Hawaii and Cerro Pachon in Chile are designed to excel in key areas, e.g. excellent sites, superb imaging quality, throughput and IR emissivity, and the capability to exploit the best observing conditions with innovative scheduling.

However, providing two superb telescopes is only part of the job. If Gemini is to attain this prominent role in astronomy, the telescopes must be operated in a fashion to allow the partner communities to effectively and efficiently carryout frontier observations, and the Gemini instrumentation capabilities have to continue to evolve to exploit new scientific opportunities and technology developments as they become available.

The capabilities of the initial complement of instrumentation (Table 1) will allow the Gemini communities to undertake the broad range of scientific programs identified in the Gemini Science Requirements Document. The on-going instrumentation program is intended to provide the key capabilities beyond those offered by the Phase I instrumentation that will keep the Gemini facilities at the forefront of astronomical research well into the 21st century.

Table 1. Gemini Phase I Instrumentation


Wavelength Range

Array Format

Pixel Scale

FOV/Slit Length

Spectral Resolution

Other Capabilities

Upgrade Options


Multi-Object Spectrograph


0.4 - 1.1µm

4k x 6k CCD


5.5 x 5.5

R~1 k (3 pix)

R~3k (3 pix)

R~10k (3 pix)

~200 multi slits 0.2" pix IFU


0.1" pix IFU


Near IR Imager


1 - 5.5µm

1k x 1k InSb




20" x 20"

50" x 50"

110" x 110"

Filters to R~100

R~700 grism

Polarizing prism

Near IR WFS (t/t) Coronagraph

Near IR Spectrograph


1 - 5.5µm

1k x 1k InSb





R=2k, 6k, 18k R=0.7k, 2k, 6k.

X Dispersion Polarizing Prism Near IR WFS (t/t)

1 - 2.5µm 0.05" pix IFU R~30k

Adaptive Optics System (AOS)

1 - 2.5µm

0.8 - 5.5µm (goal)

2' dia

natural guide star conjugation to alt. feed all inst. ports 0.5 - 2.5µm ADC

Laser Beacon

SR=0.4 at 1.6 um, median seeing and bright guide stars


Multi-Object Spectrograph


0.38 - 1.1µm

4k x 6k CCD


5.5' x 5.5'

R~ 1 k (3 pix) R~3k (3 pix) R~10k (3 pix)

~200 multi slits 0.2" pix IFU

1 - 1.5µm

0.1" pix IFU


High Resolution Optical Spectrometer


0.30 - 1.1µm

4k x 4k CCD


30k - 80k

Cass mounted

Prism X Dispersion

R= 120k

Multi object Hi Stab Lab Feed Polarizing Prism

Mid-IR Imager

8 - 25µm

~256 x 256


40" x 40"

Filters to R~100

In order to ensure the continuing relevance of the Gemini On-going Instrumentation Program, international scientific reviews will be held every two years, providing an opportunity to reevaluate the content and direction of the instrumentation program from a scientific and technical perspective, taking into account changing scientific opportunities, the evolution of technology opportunities, the status of the on-going instrumentation activities, and the availability of funds. The First of these International Gemini Instrumentation Workshops was held at Cosener's House, Abingdon, England on 18, 19 January 1997.

The Workshop assumed that the Gemini Phase I instrumentation program, which is currently in process, will be completed in full.

Section II summarizes the key scientific issues and opportunities identified by the Workshop. These are not intended to be comprehensive but rather to illustrate the type of programs judged to be high priority for Gemini, and are only a small subset of the potentially significant research areas for Gemini. Based on these scientific issues and opportunities, and the special characteristics of the Gemini Telescopes, instrument capabilities were derived, which together with the capabilities of the Phase I Instrumentation Program were judged to address the broad key issues in an effective fashion. Phasing of the instrumentation developments and location on Gemini-N/S were included in the considerations when appropriate. The resulting recommendations of capabilities are outlined in Section III. The recommendations include new instrumentation capabilities, upgrades to the baseline capabilities of the Phase I instrumentation and also instrumentation shared between the Gemini telescopes and other telescopes on the two sites.

The recommendations generated by the Workshop will be adopted as guidelines for formulating the Gemini on-going instrumentation program. Due to funding constraints and technological considerations it may not be possible to implement all these recommendations.

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