THE SPECTRA OF COMETS
Introduction
- Linear 2000WM1
Spectrum of comet LINEAR 2000 MW 1
In the picture 1 is shown the spectrum of comet C/2000 WM1. Even if this comet was a
6th mag object, the spectrum is faint because only few of the light of the comet can
enter the narrow slit of the spectrograph. The coma of this comet, as seen in a
binocular, was about 10’ while the slit covered only 2x30” over the sky. Moreover
the sky was a little cloudy masking the comet's spectrum and reflecting more light
from the nearby town.
Nevertheless we can see the three Swan bands (the yellow one is partially overlapped by
the Hg emission from street lamps) and CN band superposed to the reflected solar
continuum.
The comet was at a distance from sun of 1,18 AU and was so bright only because it was
rather close to earth, only 0,32 AU from earth.
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Picture 1: Spectrum of comet C/2000 WM1 (Linear) registered on 3.83 dec. 2001
with 10 min exposure for each one of the three spectral fields necessary to cover the
full 3800-6500 Å range with 5 Å resolution. Lack of data around 5800 Å is due to
missing overlap between spectral fields.
The telescope we used is a Cassegrain 0.6 m reflector at F/20 thus the slit spans
30x2 arc seconds with the long size aligned with R.A.
The spectrograph is equipped with a f=300 collimating spherical mirror, a 600 lines/mm
grating and a 50 mm focusing lens camera. Dispersion on CCD is 2,6 Å/pixel .
The CCD is an MX5 12 bit 512x290 camera.
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Go to introduction or other comets spectra:
Introduction
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