BRIEF Minutes for SAC telecon #5 10/15/97
Participants: Baldwin, Diaz, Dottori, Elston, Simkin (chair
& minutes) (Beers and Loh part time)
Conversation lasted 1 hr.
The telecon was suppose to be
devoted to a discussion of
Science drivers for the instruments.
These were defined as: FOV, resolution, wavelength coverage,
band width, and S/N.
Concerns about Priorities:
Baldwin reiterated that we needed to ensure that the
instrument volumes discussed by Blanco at the October 1
telecon are large enough to accomidate an optical spectrograph
Later in the discussion a concern was raised that
the introduction of Adaptive Optics might make our first light
instruments obsolete because we would need detectors with higher
resolution to take advantage of 0.05" images.
Sub group Leaders:
It was decided that each working group would be "chaired" by a SAC member.
I believe we decided upon the following: (Please indicate if this is
incorrect and I will change it).
Instrument interface requirements: Baldwin
Imagers: IR + Optical: McMahan (because not present)
Optical spectrographs: Diaz
IR spectrographs: Elston
Instrument image degradation limits: Diaz?
Wavefront sensors: Dottori?
Adaptive Optics: Simkin
Science Drivers for IR spectrographs:
Elston noted that FOV depended on whether or not a multiobject spectrograph
was planned. Spectral resolution was best around R=2000. Stellar work
might require R=10,000. Wavelength coverage should be at least 1 to 2.5
microns but could be 1 to 5 microns and bandwidth would depend on R.
A discussion of the trade-offs between detector sensitivity and
wavelength sensitivity ensued briefly
Science Drivers for IR + Optical Imagers:
These were not articulated. It was noted that simultanious IR and Optical
imaging was not pratical because IR images were short exposueres and
"dithered" while optical images were much longer exposures.
Science Drivers for Optical spectrographs:
A long discussion based on a meeting which took place in Brazil the
day before came to these conclusions: A desire to cover the
entire wavelenght range UV to Near IR in one exposure lead to the
idea of wavelength coverage from 360nm to 800nm with R=10,000 and
FOV of 5 to 7'. It was noted by Baldwin and Beers (and seconded by Simkin)
that the specvtral region below 360nm is very valuable for both AGN and
stellar work. The possibility of a spectrograph which allowed red
or blue coverage as a simple switching option was discussed.
Progress on defining instrument interface requirements:
Baldwin stated that this group had met and seemed to be converging
onto a "why reinvent the wheel" philosophy (ie adopt Gemini standards
where ever reasonable).
Future Oct. SAC meetings? These have not been planned yet.