Red Barn Observatory MPC-H68
Established 2006
Ty Ty, Georgia, USA
SOHO - Solar and Heliospheric Observatory

What is SOHO?

SOHO is a satellite that orbits within the Earths L1 (Lagrangian1) orbital point and it continuously monitors the Sun.  SOHO is a project that is carried out by the ESA
(European Space Agency) and the US NASA (Nautical Aeronautics and Space Administration).  It's primary purpose is to study and gather as much information about
the entire Sun's properties that includes the internal structure, it's atmosphere, the solar winds and it's gasses that are continuously streaming across our solar
system.  It was safely launched by an Atlas II-AS rocket on December 2, 1995 and is still working very well in space today (more than 10 years later.)  Once SOHO had
began it's normal operations, it was found to have another scientific use.  Instead of just studying the sun--it is now the worlds most successful comet hunter.  

Check out the SOHO web site!

What is a SOHO Comet?

A SOHO comet can be described as any cometary object discovered by use of the LASCO/SOHO satellite, usually by means of the Internet.  So far, over 1100 SOHO
comets have been discovered with SOHO and hopefully there will be many more. Most of these comets belong to a "group" of comets known as Kreutz comets. These
comets, the Kreutz comets, tend to follow a predicted path through the SOHO FOV (field of view) always traveling in a path toward the near edge of the visible sun
ending their long journey. There are several groups of SOHO comets. These comets are often described as "sungrazers" (sungrazing comets). Other groups of
SOHO comets are the Meyer group, Marsden group, Kracht and Kracht II group, and the Non-Group.  *Most* of these comets do not survive perihelion (their point of
orbit nearest to the Sun).

Kreutz Group:  In the late 1800s Heinrich Kreutz began studying the sungrazing comets and discovered that many of them appeared to share a similar orbit. These
comets finally became known as Kreutz Group Comets named after Heinrich Kreutz. The Kreutz group comets are the most abundant of all sungrazers. Over 80% of
all sungrazers are Kreutz comets.  Once it was discovered that the comets can be discovered within the SOHO images, a second group of Kreutz comets was
discovered. Now, the Kreutz group comets are divided into two groups--Kreutz group I and Kreutz group II.  More about Kreutz Group comets here.

Meyer Group:  Maik Meyer was the first to notice that comets 1997 L2, 2001 E1 and 2001 X8 were similar to one another and could potentially be related objects.  
Dr. Brian Marsden of Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, confirmed this in MPEC 2002-C28.  Therefore, this particular group of
comets have been named Meyer group comets after their discoverer Maik Meyer.  Ever since their discovery, more than 65 of these comets have been identified.  
Rainer Kracht has done a wonderful job of identifying their tracks throughout the C2 SOHO images here.    

Marsden Group:  This group of comets was discovered by Dr. Brian Marsden.  He posted his discovery in MPEC 2004-X73 and to date, there has been more than
30 of these comets discovered and linked.   

Kracht Group I & II:  Rainer Kracht has discovered over 170 SOHO comets.  He is the leader in comet discoveries and he has also discovered two groups of comets.
 His first group, the Kracht group, contains more than 25 members and more are being found each year.  The Kracht II group only contains three members, but they
are definitely related.  Rainer's website contains information on all SOHO comets.  

Non-Group Comets:  Every-so-often, a stray comet (belonging to no known group) will move into SOHO's FOV.  These comets are known as Non-Group comets.  So
far, there has been more than fifty of these comets discovered in the SOHO images.  They can sporadically appear at any time and they can enter the FOV from any

Now with all that said, would you like to try your luck at discovering your own SOHO comet?  If so, here's a brief introduction on searching for these kamikaze
snowballs!  SOHO Comet Hunting!