Optical or Infrared — the Elusive Boundary

  • Ian S. McLean
Conference paper
Part of the Santa Cruz Summer Workshops in Astronomy and Astrophysics book series (SANTA CRUZ)

Abstract

In years gone by, the “near infrared” part of the spectrum was considered to be the region just redward of 7000 Å, where the human eye was no longer sensitive. With the advent of semiconductor silicon array technology for imaging applications at very low light levels, optical astronomy extended its territorial claims to 1.1 microns — the cut-off wavelength defined by the silicon band-gap. Now, in the past few years, solid-state arrays employing lower band-gap semiconductors have become commercially available for IR imaging out to much longer wavelengths. So where is the optical-IR boundary? In this paper I suggest that it is at a wavelength of about 2.5 microns and therefore the availability of IR arrays of short-wavelength cut-off material, like Mercury-Cadmium-Telluride (HgCdTe), is an extremely important development for “optical” observatories.

Keywords

Dust Attenuation Emissivity Alan 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    CG. Wynn-Williams, E.E. Becklin (eds.), “Infrared Astronomy with Arrays” (University of Hawaii, Institute for Astronomy, 1987).Google Scholar
  2. 2.
    G.H. Herbig, D.M. Terndrup, Ap.J., 307 (1986).Google Scholar
  3. 3.
    I.S. McLean, T.C. Chuter, M.J. McCaughrean, J.T. Rayner in “Instrumentation in Astronomy VI”, David L. Crawford, editor, Proc. SPIE 627, 430–437 (1986).Google Scholar

Copyright information

© Springer-Verlag New York Inc. 1988

Authors and Affiliations

  • Ian S. McLean

There are no affiliations available

Personalised recommendations