(a) Using data available in the text or on observatory...

(a) Using data available in the text or on observatory websites, list the wavelength ranges (in $\mathrm{cm}$ ) and photon energy ranges (in eV) covered by the following telescopes: VLA, ALMA, SIRTF, JWST, VLT/VLTI, Keck/Keck Interferometer, HST, IUE, EUVE, Chandra, CGRO. (b) Graphically illustrate the wavelength coverage of each of the telescopes listed in part (a) by drawing a horizontal bar over a horizontal axis like the one shown in Fig. 25 FIGURE 25 The transparency of Earth's atmosphere as a function of wavelength. (c) Using photon energies rather than wavelengths, create a graphic similar to the one in part (b)

(a) Using data available in the text or on observatory websites, list the wavelength ranges (in $\mathrm{cm}$ ) and photon energy ranges (in eV) covered by the following telescopes: VLA, ALMA, SIRTF, JWST, VLT/VLTI, Keck/Keck Interferometer, HST, IUE, EUVE, Chandra, CGRO.
(b) Graphically illustrate the wavelength coverage of each of the telescopes listed in part (a) by drawing a horizontal bar over a horizontal axis like the one shown in Fig. 25
FIGURE 25 The transparency of Earth's atmosphere as a function of wavelength.
(c) Using photon energies rather than wavelengths, create a graphic similar to the one in part (b)

Key Concepts

Atmospheric Transparency

Earth's atmosphere is only transparent to certain wavelengths of electromagnetic radiation, meaning that some wavelengths are absorbed or scattered before they reach ground-based instruments. This characteristic of atmospheric transmission drives the need for space-based telescopes for observations in spectral regions that are blocked by the atmosphere, such as most ultraviolet, X-ray, and gamma-ray wavelengths.

Observational Instrumentation

Different telescopes and observatories are designed to be sensitive to specific ranges of the electromagnetic spectrum, which in turn determine the types of astronomical objects and processes that can be studied. Selecting the appropriate instrument for an observation involves matching the telescope’s wavelength (or photon energy) coverage with the emission characteristics of the target phenomena.

Graphical Data Representation

Graphically representing the wavelength or photon energy coverage of telescopes involves plotting horizontal bars along an axis that represents the electromagnetic spectrum. Such visualizations provide an intuitive way to compare the operational ranges of various telescopes and to understand the gaps and overlaps in observational coverage, aiding in the planning of multiwavelength studies.

Electromagnetic Spectrum

The electromagnetic spectrum encompasses the full range of electromagnetic radiation types, from radio waves with long wavelengths and low photon energies to gamma rays with very short wavelengths and high photon energies. Understanding this spectrum is fundamental in astronomy since different celestial phenomena emit radiation in distinct parts of the spectrum, which informs the design and operation of observational instruments.

Wavelength and Photon Energy Relationship

The relationship between wavelength and photon energy is governed by the equation E = hc/?, where E is the photon energy, h is Planck’s constant, c is the speed of light, and ? is the wavelength. This conversion is crucial, as telescope specifications are often given in either wavelength or photon energy units. Converting between these units allows astronomers to compare instrument capabilities and make appropriate observational choices.

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