Operation year

    CARMENES [kár-men-es] (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs) is a next-generation instrument built for the 3.5m telescope at the Calar Alto Observatory by a consortium of German and Spanish institutions. It consists of two separated spectrographs covering the wavelength ranges from 0.52 to 0.96 µm and from 0.96 to 1.71 µm with spectral resolutions R = 80,000-100,000, each of which performs high-accuracy radial-velocity measurements (∼1 m s-1) with long-term stability. The fundamental science objective of CARMENES is to carry out a survey of ∼300 late-type main-sequence stars with the goal of detecting low-mass planets in their habitable zones.

    Summary table

      VIS channel NIR channel
    Wavelength coverage, Δλ* 520-960 nm
    960-1710 nm
    Detector 1 x 4kx4k e2v CCD231-84 2 x 2kx2k Hawaii-2RG
    (2.5 μm cutoff)
    Wavelength calibration Th-Ne lamps & Fabry-Pérot etalon U-Ne lamps & Fabry-Pérot etalon
    Working temperature, Twork 285.000 ± 0.005 K 140.000 ± 0.005 K
    Spectral resolution, R 94,600 80,400
    Mean sampling 2.8 pixels
    Mean inter-fibre spacing 7.0 pixels
    Cross disperser Grism, LF5 glass Grism, infrasil
    Reflective optics coating Silver Gold
    No. of orders 55 28
    Échelle grating 2 x Richardson Gratings R4 (31.6 mm-1)
    Target fibre field of view 1.5 arcsec
    A&G system field of view 3 arcmin
    A&G system band Approx. R

    *: There is a dichroic at 960 nm that splits the light into two beams, one for each channel. The detectors are actually sensitive until 1050 nm (VIS) and from 900 nm (NIR). There are some gaps in the wavelength coverage wider than 10 nm redwards of 1550 nm. The strongest telluric absorption is at the JH boundary

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