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M1 - The Crab Nebula in Taurus
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Copyright 2010 Hap Griffin In the year 1054
AD, Chinese astronomers recorded an explosion in the sky that was four times
brighter than Venus and was visible in daylight for several weeks
afterwards. From those ancient records, modern day astronomers have
determined that the object pictured here, designated M1 in Charles Messier's
famous list and known informally as the Crab Nebula, is the remnant of a colossal
supernova explosion. The structure of
M1 consists of twisting red filaments of material from the progenitor star
glowing at the hydrogen-alpha wavelength. The ghostly blue glow permeating
the remainder of the nebula is caused by synchrotron radiation being emitted
from the rapidly spinning pulsar at its center...the highly compressed core of
the original star. The explosion of its outer layers compressed the core
from an original size similar to that of our sun into an object that is only
about 10 kilometers in diameter. Thus its mass density is trillions
of times that of lead. Since the core is much smaller than the original
star but retains much of its rotational momentum, its rotation has sped up to
where it is now rotating at 30 revolutions per second...much as a spinning ice
skater spins more rapidly as she pulls her arms in. The rotating core
spews out a powerful stream of high energy electrons from its magnetic poles
which aim in our direction once each rotation. It was these powerful beams
of radiation that were first detected in 1968 pulsing at a rate of 30 times each
second that at first led radio-astronomers to believe that they may have found a
sign of an intelligent civilization. Once the pulsing source was
correlated with the optical location of the Crab supernova remnant, the nature
of this new class of star was determined. In the years since, many other
pulsars have been detected. M1 is expanding at
a rate of approximately 1800 kilometers per second and now has a diameter of
roughly 10 light-years. It lies at a distance of 6300 light years from
earth.
Date/Location:
January 9, 2010 Griffin/Hunter
Observatory Bethune, SC
Camera: QSI 583wsg
Filters: Astrodon E Series Generation 2 LRGB
CCD Temperature: -20 C
Instrument: Planewave CDK 12.5"
Focal Ratio: f/8
Mount: AP-1200
Guiding: Auto via the QSI camera's built in Off-Axis Guider
mirror and a Starlight Express Lodestar Guider
Conditions: Clear and cold
Weather: 20 F, still
Exposure: 180 minutes total (6 x 10 minutes each in RGB)
Capture: CCDAutopilot 4 w/ Maxim DL Camera Control, focused automatically w/
FocusMax
Processing: Frame calibrations, alignment and stacking with ImagesPlus v3.80.
Finishing in Photoshop CS4.