Space Observations

Space Observations
While radio waves, near-infrared (near-IR), and visible light are observable from surface of the Earth, we need to introduce tools into space to observe other frequencies of the EM-band.This section will introduce:

Near-IR
Infrared
X-Ray
Ultraviolet
Gamma Ray

Near-IR:

In order to see the small window of the near-IR spectrum from the ground, some novel approaches have been designed and implemented. Viewing of the near-IR is possible only by:

  • Very high altitude
  • Using super-cooled CCD imagery
  • Mirrors using silver or gold coated mirrors
  • Small secondary mirrors
  • Cooled telescope tubes and housings of mirrors along the optical path

An example of an infrared optimized telescope is the Keck Observatory Gemini-North telescope.

To view the residual IR spectrum, high altitude observatories – or orbiting satellites – are required. Another method is to observe from Antarctica – if you like the cold!

There are two in-flight observatories:

In addition, the following observatories are (and were) in orbit around the Earth:

X-Ray:

This high-energy portion of the EM-band is only visible from space. Between 1949 to 1962, sounding rockets traveling up to 100 km above the surface would carry Geiger counters to measure X-ray emission. A sounding rocket is nothing more than a standard rocket with the Geiger counter and other related electronics housed in within the nose.

By 1970, several orbiting X-ray observatories would begin capturing valuable data. These include the following observatories:

Objects observed by X-ray are (but not limited to) supernovaremnants, accretion disks, pulsars, and black holes.

Ultraviolet:

The ultraviolet (UV) region of the EM-band allows the study of very hot, young stars. Additionally, populations of young, hot stars within the disks of spiral galaxies are within easy view of a UV telescope. This also requires satellite observatories. Here is a list of UV observatories:

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Gamma Rays:

Gamma rays are the highest energy radiation resulting in extremely short wavelengths. Sources of gamma rays are supernovas, neutronstars, intense gravity regions and active galaxies (galaxies with a large and active black hole at the center). Here is a list of some gamma ray satellites:

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