MOSCA is a multi-purpose focal reducer, which change the 3.5m telescope f/ratio from F/10 to f2.7. With direct and FPI imaging, long slit and multiobject spectroscopy, designed to work in the visible light.

Available at: Cassegrain station of the Zeiss 3.5 m reflector

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In a nutshell

Direct Imaging:
Scale: 45 µm/" or 0.33"/pix (1pix=15μ)
FoV: 11' diameter, 2048x4096 pix CCD
Filters: 2 wheels with standard filters (Johnson, Cousins, Gunn, SDSS) and  a large set
of interference filters are available.

Fabry-Pérot Etalon:
FPI can be used as tunable filter at a spectral resolution of 15-20 Å over the wavelength range 5500 to 9500 Å.

Slit: 11' length, optionally limited with a decker, and variable width from 0.3" to 15"
Grisms: Three grism sets (250l/mm, 500 l/mm, 1000 l/mm) provide spectral dispersiions of 6Å /pix, 2.9Å /pix and 1.3Å /pix, at different wavelength ranges.

Multi object spectroscopy is possible using masks (to be made in advance) which are put in the aperture unit.


Observing with MOSCA

User's manual
Signal Calculator for imaging
Requesting observation time for MOSCA
MOSCA it is not offered in 2020B semester
Night logsheet


More information

Technical data

Wavelenght calibration lamps

Detector characteristics

Zero points