Stationed in a halo orbit around the Earth-Sun Lagrange point since 1996, the Solar and Heliospheric Observatory (SOHO) has monitored the Sun for nearly 20 years. The Large Angle and Spectrometric Coronagraph (LASCO) instrument blocks out the bright solar disk, making it easier to see the corona of plasma and dust around the Sun, normally only visible during solar eclipses. This instrument also provides a very large field of view of the region around the Sun.
In addition to the benefit of this capability in solar studies, SOHO/LASCO can see many comets which pass very close to the Sun, called 'sungrazers'. Observers on Earth rarely see these objects as they are obstructed by the Sun's glare and Earth's atmospheric scattering at sunrise and sunset. SOHO/LASCO has seen not only many known comets, but discovered many more NEW sungrazing comets. At the time of this writing, the discovery count is approaching 3000.
There are nearly 1800 comets and trajectories plotted in these visualizations which covers the time frame from January 1996 to May 2010 at the rate of one frame of the movie corresponding to one day. The great majority of these comets are Kreutz group members (the red trails). The trails are color coded based on group membership.
Yellow - unaffiliated comets
Red - Kreutz group.
Green - Meyer group
Blue - Marsden
Cyan - Kracht
Magenta - Kracht 2
Important Notes and Caveats:
This version of the visualization provides long trails for the periodic comets so the entire orbit is visible and they can be distinguished from the one-time visitors to the inner solar system. An alternate version with short trails for all comets is available at Lot of Comets - Short trail version
The Kreutz group comets rarely make it past perihelion (the closest pass to the Sun) so these orbits terminate a day after perihelion.
The Kreutz group comets appear to stream sunward in bunches. This is an artifact of the fact that it is less likely for SOHO to detect incoming Kreutz objects during some parts of the year.
The trails represent the orbital path of the comet nucleus, NOT the comet tail.