Cassiopeia A: Flamsteed's Supernova of 1680

Click on image for larger version.

While the visual impact of this image remains in the eye of the beholder- the impact of the appearence of Tycho's Star (seen in 1572 by Tycho Brahe) and this example (perhaps observed by John Flamsteed in 1680), cannot be overstated. Examples of Type Ia supernovae explosions are some of the brightest astronomical events in the universe. The sight of such changes in the celestial sphere forever shattered man's perception of an immutable universe. And so astronomers such as Tycho and many to follow concerned themselves with the causes and significance of these strange "new stars."

A Type Ia supernova is generated by the collapse of a white dwarf star. White dwarves are small and exceptionally dense stars- they are the cores of stars that have shed their outer envelopes of gas in pretty Planetary Nebulae fashion. If left alone, these white dwarves would cool (after billions of years) and become the dark kernels of former sunlike stars. However, should a white dwarf have a nearby star from which it could accrete gas (and add mass)- the extra matter pushes the white dwarf beyond the limit of stable existence and it explodes in dramatic fashion.

Re-discovered in 1952 by radio astronomy, the remains of this star still glow in many wavelengths of light. Later the 200in Palomar telescope detected the dim remains of this star in optical wavelengths. Interestingly this image with amatuer equipment far exceeds images in optical light from the telescopic giants of yesteryear. This gas is expanding at velocities of millions of miles per hour. Currently the shell of gas is around 10 light years in diameter and has a temperature of around 50 million degrees. Cass A is considered the most recent supernova explosion that has been observed in our galaxy. Unfortunately interstellar dust may have dimmed the initial explosion so that it went unnoticed by most of humanity. Like the Crab Nebula, these kinds of star deaths infuse heavy elements of matter into the galaxy... elements that may later coalesce to become planets and people.


20in RC Optical Systems telescope Operating at f/8.4
Paramount ME Robotic Telescope Mount
SBIG ST10XME CCD camera with color filter wheel

L R G B color production was used to create this image.

Luminance = 330 minutes binned 1x1
Red = 20 minutes binned 3x3
Green = 20 minutes binned 3x3
Blue = 20 minutes binned 3x3

  • 120 minutes of luminance data was, unfortunately, inadvertantly taken through the RED filter. It was used, but the effective luminance exposure is less than the "clear" 330 minutes quoted above.
  • One iteration of L-R deconvolution (sharpening) algorithm using CCDsharp was applied to the luminance image.

  • The AO unit was used to acquire this image.
  • Minimum credit line: Doug Matthews and Charles Betts/Adam Block/NOAO/AURA/NSF

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    Updated: 10/07/2003