DeVeny Optical Spectrograph

The DeVeny Spectrograph is a moderate resolution optical spectrograph working between 3200 Å and 1 µm.  R ranges between 500 and 4000 depending upon the grating used.  The DeVeny spectrograph was built and known at Kitt Peak National Observatory (KPNO) as the KPNO White Spectrograph, and had a long career at the 36″ telescope there before being retired.  Lowell Observatory acquired the spectrograph from KPNO on indefinite loan in 1998.  A new CCD camera was built for it, and the instrument was further modified for installation on the 72” Perkins telescope in 2005.  Following 8 years of service there, it was removed in 2013 for upgrades for installation on the LDT.  The DeVeny spectrograph has been in use on the instrument cube since February 2015.

There are currently 10 gratings available for use. Five have recently been made available thanks to a long term loan from KPNO and have not yet been well characterized at the LDT.  Note that swapping the grating remains a daytime operation to minimize risk.

See DeVeny on Confluence

Specifications

  • Spectral Channel CCD
    • Detector: e2v CCD42-10 deep depletion device: 2048×512 13.5 µm pixels (27.65 mm × 6.91 mm)
    • Slit Length: 2.5′
    • Pixel Scale: 0.34″/pixel (spatial direction)
    • Gain: 1.52 e−/ADU
    • Read Noise: 3.2 ADUs, about 4.9 e−
    • Normal Operating Temperature: −110ºC
    • Linearity: TBD
    • Readout Time: 8 s
    • Dark Current: TBD
    • Fringing: 1-3% fringe amplitudes, redward of 8000 Å
  • Slit Viewing Camera
    • Model: Lodestar X2 by Starlight Xpress
    • Pixel Scale: 0.253″/pixel (binned 2 × 2)
    • Image Size: 376 × 290 pixels
    • Field of View: 95″ × 73″
  • Grating Complement
    • Collection of 10 gratings that were used with the KPNO White and Gold spectrographs
    • 128 × 154 mm plane reflection gratings
    • Range of spectral resolution from R ∼ 500 − 4000
    • 1st order blazed gratings
    • Motorized grating tilt angle stage to select central wavelength on the CCD
  • Calibration Lamps
    • For wavelength calibration, there are four remotely-controlled AC-powered pencil-style gas discharge arc lamps:
      • Neon (∼ 5800 − 8600 Å)
      • Argon (∼ 6900 − 9700 Å)
      • Mercury (∼ 3300 − 5800 Å)
      • Cadmium (∼ 3200 − 5500 Å)
    • The primary dome flat field calibration lamps are on the top ring of the secondary mirror support structure.

LDT Instrumentation

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