Studies of astronomical seeing at the Canada France Hawaii Telescope (CFHT) site, from both inside and outside the
dome, show that the full potential of the excellent seeing conditions at the CFHT site has never been fully exploited.
These studies indicate that this is due to the classical unvented hemispherical CFHT dome. Tests have been performed
to identify the causes of the “pathologies” revealed by these seeing studies and to find ways of mitigating them. In
particular, we have investigated installing vents in the dome skin to improve air exchange between outside and inside the
enclosure. A number of vent geometries were tested using water tunnel models at the University of Washington
Aerodynamics Laboratory (UWAL). Relative flushing times for various dome slit to prevailing wind directions were
compared for the different vent geometries. The general flow characteristics observed with these low Reynolds number
tests were compared with computational fluid dynamics (CFD) simulations of the CFHT dome performed in
collaboration with the Thirty Meter Telescope (TMT) project, as well as low-speed wind-tunnel tests and visualization of
the flow around the actual observatory building.
SPIRou is a near-infrared, echelle spectropolarimeter/velocimeter under design for the 3.6m Canada-France-
Hawaii Telescope (CFHT) on Mauna Kea, Hawaii. The unique scientific capabilities and technical design features
are described in the accompanying papers at this conference. In this paper we focus on the data reduction software
(DRS) and the data simulation tool. The SPIRou DRS builds upon the experience of the existing SOPHIE,
HARPS and ESPADONS spectrographs; class-leaders instruments for high-precision RV measurements and
spectropolarimetry. While SPIRou shares many characteristics with these instruments, moving to the near-
infrared domain brings specific data-processing challenges: the presence of a large number of telluric absorption
lines, strong emission sky lines, thermal background, science arrays with poorer cosmetics, etc. In order for the
DRS to be fully functional for SPIRou's first light in 2015, we developed a data simulation tool that incorporates
numerous instrumental and observational e_ects. We present an overview of the DRS and the simulation tool
As part of the image quality (IQ) assessment and improvement initiative being carried out at the 3.6m Canada
France Hawaii Telescope (CFHT) on Mauna Kea, Hawaii, our objective in the work reported here is to obtain
a systematic assay of thermal sources within the dome and in the summit environment around the observatory,
and therefore mitigate their contributions to convective instability leading to 'dome seeing'. Toward this, we
undertook a nighttime overflight to capture thermal images with a calibrated infrared camera of the outer
structures of CFHT and the neighboring observatories on the summit ridge, as well as of a significant area
of the surrounding terrain. The same thermal camera was then used to image heat sources within the dome.
Using a convective heat transfer model, all these measured surface temperatures were converted to heat fluxes,
and thus used to build a thermal assay of the dome. In addition, using button type temperature loggers, we
simultaneously recorded the nighttime dome skin temperatures of CFHT and two other observatories over a
weeklong period to evaluate nighttime supercooling of the dome skin due to radiation to the cold night sky. As a
complementary goal we compared the efficacy of different paints and coatings used in observatories to minimize
this effect. Though similar studies have been carried out at other observatories, the results are rarely available
in published literature. Therefore, here we explain our methodologies, along with a detailed discussion of our
results and inferences to serve as a useful resource to the larger observing community.
A prototype genetic algorithm (GA) is being developed to provide assisted and ultimately automated observation
scheduling functionality. Harnessing the logic developed for manual queue preparation, the GA can build suitable sets of
queues for the potential combinations of environmental and atmospheric conditions. Evolving one step further, the GA
can select the most suitable observation for any moment in time, based on allocated priorities, agency balances, and realtime
availability of the skies' condition.