ESOPO Conceptual Design
Abstract
IAUNAM is building an optical, high efficiency, intermediate-low dispersion spectrograph (R ∼ 5000 - 500) for general astronomical purposes, for use at the cassegrain f /7.5 focus of the 2.1-m telescope after-guider. The instrument should cover simultaneously a spectral range of 3500 - 9000 Å, with a long slit with spatial field of view no less than 8 arc minutes. To achieve large spectral coverage and resolution simultaneously, ESOPO has two arms divided through a dichroic mirror. A blue arm optimized for 3500-7000 Å, and a red arm optimized for 4500-9000 Å, with significative overlap. They can be used separately, or combined. Optimal resolution is achieved by selecting the appropriate gratings. Acquisition and reduction of data have to be pipe-line like. The TOP Level Requirements are: Minimum System Efficiency: For the entire instrument without telescope, 15% at 3,500Å, 35% at 4,500Å, 36% at 5,500Å, 40% at 7,500Å, 15% at 9,000Å. Overall objective (excluding telescope, grating, dichroic mirror and CCD) 80% at 3,500-9,000Å. Resolution: R ∼ 2000 or higher. Sky limited, pixel noise due to sky photons higher than detector noise (readout and dark current). Maximum real spectral resolution: R ∼ 5000 (FWHM) with nominal slit of 0.8 arcsec via density gratings not greater than 1200 || /mm and maximum dimensions of 154×206mm. It must not vary more than 10% along slit (goal 5%). Field (length of slit): More than 8' with goal of 10'. Full field of view should be visible. Detector noise: < 8e^-. Linear response at least up to S/N {2}50. Linear well > 62, 500e^-. Width of slit: Minimum: ≤ diffraction limit of spectrograph. Maximum: > 9 arcsec (goal > 10 arcsec ).
- Publication:
-
Revista Mexicana de Astronomia y Astrofisica Conference Series
- Pub Date:
- June 2006
- Bibcode:
- 2006RMxAC..26..208P