ASTR1001 Assigment 1: Supplementary Data Release.

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ASTR1001 Assigment 1 Supplementary Data Release.

• More information for the science team of the USS
  Drongo

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More Information

• In response to popular demand, here is some more
  information gleaned by the astrophysics team of
  the USS Drongo.
• You may or may not find this extra information
  valuable!
• You dont need to use this additional information
  to get a decent mark - but if you want an
  extremely high mark, you should make what use you
  can of this new information.

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Communications and Scanners Division

• The Communications and Scanners division were
  excited by your report of the strange, bright
  featureless moon, so they turned their equipment
  on it, before it set.
• Here is what they found.

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Radar

• They used the USS Drongos powerful main radio
  communications array to beam an intense pulse of
  radio emission at the moon.
• A reflection of this pulse was detected, 4.56
  seconds after the original pulse was sent.

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Spectrum

• Next, they turned their spectral scanners onto
  the moon.
• This was done just before it set. At this point,
  the lower half of the moon was bright, while
  the top half was dark.

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Bright Half

• Here is the spectrum of the bright (illuminated)
  half, at optical wavelengths.
• This is a plot of energy per unit wavelength
  (y-axis) against wavelength (x-axis)

An Angstrom is 0.1 nano-metres
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Night Side

• No optical emission was detected from the dark
  side of the moon.
• However, strong emission was detected at near
  infra-red wavelengths, shown here.
• Furthermore, this emission varied with time - the
  green and red lines show different spectra taken
  four hours apart.

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IR Bumps

• Clearly most of the IR emission from the dark
  side comes out at particular wavelengths, forming
  bumps in the spectrum.
• One of the scanners was tuned to look only at
  emission at the wavelength of one of these bumps
  the one at a wavelength of 2.3 microns
  (micro-metres).
• It was then pointed at the moon

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Pictures of the Moon.
Here are four pictures of the emission at this
wavelength. They were taken at four hour
intervals, just before it set. The order is
indicated by the numbers. The bottom right of
each image is masked off to avoid the scanned
being swamped by emission from the bright side of
the moon.
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