Gemini telescope

The Gemini telescopes have to be near diffraction limited in the infrared (or contribute no more than 0.2 arcsecond to images in the optical). On windy sites like Mauna Kea and Cerro Pachon the telescopes have to be active in order to adueve this. The entire facility must therefore be considered as a system, which includes not just the telescope, but enclosure, acquisition and guiding philosophies as well as the instruments. 

For example, imagine that you are observing on a Gemini Telescope and... 

EUerbroek, B.L., Adaptive Optics Modeling for the GEMINI Telescopes, Internal Report, (July 1993). 

Figure 17. Steps in the constmction of a datacube of the nucleus of NGC1068 from observations with the integral held unit of the Gemini Multiobject Spectrograph installed on the Gemini-north telescope. The datacube is illustrated by a few spectra distributed over the field and equivalently by a few slices at a given radial velocity in the light of the [OIII]5007 emission line. Only a few percent of the total data content is shown.

Gemini North Observatory/CTI Mode-locked SFG Laser. CTT is developing the first commercial solid-state Na LGS system. It will be installed on the center section of the 8-m Gemini North telescope, with the output beam relayed to a projector behind the secondary mirror. The projected beam is required to be 10-20 W power, with M2 < 1.5. The architecture is based on sum-frequency mixing two mode-locked solid-state Nd YAG lasers. The mode-locked format provides significantly higher peak intensity than CW, enabling more efficient SFG conversion. The laser is also free of the thermal and intensity transients that are inherent in the macro pulse format. The chosen... 

The only 3D mapping system with LGSs under constmction today is that for the Gemini South 8m telescope at Cerro Pachon, Chile (Lllerbroek et al., 2002). It consists of 5 LGSs, 3 deformable mirrors with a total of 769 actuators and one 1020 subapertures wavefront sensor per LGS (Fig. 11). It is expected to be the most performing MCAO device. 

Figure 11. Layout of the multiconjugate adaptive optics with 5 LGSs at the Gemini South 8m telescope (F. Rigaut, private communication).

Next steps toward experimental works will be particularly exciting the MCAO MAD bench at ESO, the MCAO+LGSs device at Gemini South, experiments at the MMT and at Mt Wilson, the polychromatic LGS demonstrator in France. Also we still have a lot to learn with the feedback from the devices running now or very shortly, at Lick, Keck and ESO. But the biggest challenge of the coming years wdl be to extrapolate this know how to the case of decametric or even hectometric optical telescopes. 

Recent observations of the HF (1-0) R9 line at 2.3 /tm with the Phoenix spectrograph on the Gemini-South telescope has opened a new window that sheds light on understanding the chemical evolution of fluorine and the nuclear processes that produce this element. Until recently, only a small number of observations of fluorine were available and the trend of fluorine abundances with metallicity had yet to be probed in the Galaxy. 

Bob raises an eyebrow. My favorite is Castor, in the Gemini constellation. It has at least six component stars in a crazy gravitational orgy. Though Castor appears as a single star to the naked eye, a telescope resolves this into two closely spaced stars, Castor A and Castor B, and a distant, dim red companion named Castor C. ... 

Fig. 1. The Gemini F/16 emd F/6 configuiations. These ate Cassegrain only telescopes. The telescope designs are shown in Figure.1.

However, to realize and e q>loit the superb image quality with these telescopes at infrared wavelengths, a different approach to designing infrared instruments for Gemini is required. 

So in setting for this type of experiment with Gemini, the observer, or the telescope operator, wUl have to find at least two guide stars. The first is required for wavefront sensing. The second is needed for the fast tip-tUt sensor, which wUl have to be positioned within the isokinetic patch of the science objects and wiU probably be within the field of view of your instru-... 

Adaptive Optics on 8 meter telescopes can offer significant scientific gains at near IR wavelengths. As part of the Science Requirements GEMINI will be implementing a facility Adaptive Optics System on the Mauna Kea telescope as part of the construction phase of the project. 

Dinger, A. St. C., Thermal Emissivity Analysis of a GEMINI 8 meter Telescope Design, Gemini Technical Report RPT-SFS-G0200, (August 1993). 

Robertson, D.J., EUerbroek, B.L., McGonegal, R.J., Mountain, C.M., Osdunann, J. and Pompea, S.M., Adaptive Optics Modeling for the GEMINI 8-m Telescopes Project, ICO-16 satellite conference on Active and Adaptive Optics, In Print. 

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