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Sharing Time on the Blanco 4-m and the ESO 3.6-m Telescopes (1Mar96) (from CTIO, NOAO Newsletter No. 45, March 1996) To make more efficient use of the astronomical observing potential of our two institutions, as well as to foster closer cooperation, CTIO and ESO are beginning an experiment to exchange 4-m class telescope time. The exchange will start with the next proposal period (CTIO, second semester 1996, ESO period 58). The instruments available for the use of the US community on the ESO 3.6-m are: (1) ADONIS: An adaptive optics system for 1-5 m. (2) TIMMI: A thermal infrared imager and spectrometer. (3) EFOSC: An optical multi-slit spectrograph, imaging polarimeter, spectropolarimeter and imaging coronagraph. This array of instrumental options provides our user community with capabilities not yet offered on CTIO telescopes. A brief outline of the performance of each of these ESO instruments follows. Prospective users are encouraged to refer to the documentation on the ESO WWW pages for more details (see references below). Users from the ESO community have asked for access to our infrared spectrograph (IRS). We have tentatively agreed to "swap" 12 nights per semester, and envision this initial attempt to run for three semesters. The exact number of nights will be determined by scientific merit and proposal pressure. Proposers from the NOAO/CTIO community who wish to use these ESO instruments should submit a proposal to CTIO on our normal telescope request form, but indicate clearly on the front page which ESO instrument is requested. Proposals will be rated by the CTIO TAC based on scientific merit, and then passed to the ESO scheduler, and vice versa. Input to the TAC from the appropriate technical reviewers of the instrument host institution will be sought. Note that because of differences between semesters, the time being sought for the ESO instruments will only be 1 October 1996 to 31 March 1997. ESO use of the Blanco 4-m instruments will occur in the 1 August 1996 to 31 January 1997 period. Also, prospective users of EFOSC should note that the available nights will be limited to bright or gray (7 to 10 nights from new moon) lunar phases. ADONIS This is a near-infrared adaptive optics system. It uses an optical wave-front sensor to control both a tip-tilt mirror and a deformable mirror that correct for both tilt and higher spatial frequencies. The wavefront sensor requires a reference object smaller than 2" to 3" in diameter and brighter than V = 13 to be located within 40" of program object; the program object itself may be used as the reference object if it is sufficiently bright. ADONIS has produced K-band images with a FWHM of 0.2" which approaches the diffraction limit of the 3.6-m at 2.2um (0.12"). Although ADONIS is available to observers now, it will not be fully commissioned until the end of 1996. In the meantime, the instrument is offered on a shared-risk basis. Two IR cameras are available: SHARP II 256 x 256 HgCdTe array (NICMOS 3) 1-2.5 um, filters for J, H, K , K' + narrow bands; RON 40 e-; full well 200,000 e- scales; 0.035"/pixel, 0.050"/pixel and 0.100"/pixel; sensitivity: J/H/K 22.1/22.2/20.1 (1 hour, S/N = 5, 0.1"/pixel) COMIC 128 x 128 HgCdTe array 1-5 um, filters for J, H, K, K', L, M + narrow bands; RON 400 e-; full well 6.8 x 10 sup 6 e-; scale: 0.035"/ pixel (J,H,K); 0.100"/pixel (L,M); sensitivity: J/H/K 18.3/18.2/17.2 (1 hour, S/N=5), L/M 14.8/12.5 (10 minutes, S/N=5). No experience with AO or IR arrays is required to use ADONIS. Illustrated results can be found in ESO Messenger 75, p.33, and ESO Messenger 79, p.23. Reference: http://www.hq.eso.org/proposals/adonis.html TIMMI This is a mid-infrared imager/spectrometer, optimized for the 10 um window. It uses a 64 x 64 Ga:Si photo-conductor array, cut-off wavelength of ~ 17.8 um. imager - scales: 0.34"/pixel, 0.50"/pixel and 0.66"/pixel sensitivity: M = 9.5, N = 7.2 (10 sigma, 4 hours, 0.36"/pixel) For narrow band imaging, an integrated line flux density of ~ 1 x 10 sup -16 W m sup -2 arcsec sup -2 can be detected in 1 hour. spectrometer - choice of three grisms covering the wavelength range of 7.70-13.15 um slit: 0.9" x 35" (0.66"/pixel) resolution: R ~ 200 sensitivity: S/N = 10 in 1 hour for a flux density of 0.6 x 10 sup -14 W m sup -2 arcsec sup -2 in the [Ne II] line (12.8 um); S/N = 10 in 1 hour for a continuum source of 400-800 mJy (N ~ 4.5). Reference: http://www.hq.eso.org/proposals/timmi.html EFOSC1 This is an optical imager/spectrometer. It uses a Tektronix 512 x 512 CCD with 27 um pixels and 10 e- RON. scale: 0.61"/pixel, 5.2' x 5.2' fov, choice of grisms providing dispersions between 25 Angstroms/pixel and 3.3 Angstroms/pixel plus an R ~ 2000 cross-dispersed "echellette" mode. Only a limited number (maximum of 6) nights of grey time (7-10 days past new moon) will be available. EFOSC1 operating modes not available at CTIO: (1) Aperture plate spectroscopy, room for up to 20 objects with 15" long slitlets. (2) Polarimeter mode (imager and spectrometer) using a 20" Wollaston prism and rotating half-wave plate. (3) Coronagraphic imager. Mark Phillips, Michael Keane, Bob Schommer
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