Gemini North Observatory successfully began nighttime remote operations from the Hilo Base Facility control room in November 2015. The implementation of the Gemini North Base Facility Operations (BFO) products was a great learning experience for many of our employees, including the author of this paper, the BFO Systems Engineer.
In this paper we focus on the tailored Systems Engineering processes used for the project, the various software tools used in project support, and finally discuss the lessons learned from the Gemini North implementation. This experience and the lessons learned will be used both to aid our implementation of the Gemini South BFO in 2016, and in future technical projects at Gemini Observatory.
The Gemini Multi-Object Spectrograph (GMOS-N), with a field of view of
5.5 × 5.5 arc minutes, was used to obtain r' band images of the
Keck II laser beam. The data samples the Rayleigh scattered laser beam at low
elevations and the sodium spot at the highest elevation. The Rayleigh scattered part of
the beam is large at low elevations, filling the GMOS-N field of view, with high surface
brightness. At higher elevations (85 deg - 89.5 deg) it gets smaller and fainter. We also
present data taken on the laser spot which we see at an elevation of 89.625,
corresponding to a height in the atmosphere of ~100km. In addition, GMOS-N spectra
and GMOS-N on-instrument wavefront sensor (OIWFS) data have been collected that
allow us to characterize the effect that lasers from other telescopes might have on
GMOS-N data. The OIWFS works at wavelengths which include the sodium D band.
At Gemini Observatory, the traditional employment position of telescope operator has been discarded in favor of a more
diverse and flexible position known as System Support Associate (SSA). From the very beginning, the operational
model of Gemini was designed to involve SSAs in observatory projects well beyond the strict operation of the telescope
systems. We describe the motivation behind the original model, how it was eventually implemented and how it has
evolved. We describe how the schedule allows SSAs to assume different roles within Gemini and how flexible time
allows them to participate to a wide range of projects, increasing their motivation, deepening their knowledge and
strengthening communication between groups, as well as allowing management to allocate resources to projects that
would otherwise lack manpower. We give examples of such projects and comment on the difficulties inherent in the
model.
A Prime Focus Wavefront Sensor (PFWFS) has been designed and built at the Gemini Observatory. The system contains a Shack- Hartmann (SH) wavefront sensor and has been designed to use commercial components. The primary mirror of the 8 m Gemini Telescope has a complex active optics system that needs to be calculated during commissioning. The wavefront sensor was built to measure the image quality at prime focus, this eliminates the secondary mirror introducing supplementary aberrations. It has been successfully used during commissioning, to test the active optics.
Wavefront tilt variances have been measured directly at near infrared wavelengths with the IRCAM camera at the UK Infrared Telescope. Single aperture and differential tilt variances were obtain in the J (1.228 micrometers ), H (1.643 micrometers ), K (2.182 micrometers ) and L (3.42 micrometers ) photometric passbands using Hartmann masks containing, respectively, four and eight subapertures at a re- imaged pupil. Sampling runs at each wavelength comprised 200 short exposures taken over periods of about 35 seconds. The results have been analyzed by separating the effects of local (dome and telescope) seeing and telescope drive errors or wind shake from those of the external atmosphere. Although the measured wavefront tilt variances included contributions from these various sources, instead of the free atmosphere alone, in practice these are what currently limit the imaging performance of most astronomical telescopes at visible and infrared wavelengths.
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