1 December 2021

LASCO C1 aboard of the SOHO (SOlar Heliospheric Observatory)

The key problems concerning the physics of the solar atmosphere are still unsolved:

How is the Corona heated to more than a million degrees?
Where and how does the solar wind obtain its acceleration?
Which processes in the lower corona lead to the gigantic mass ejections observed?

To gain some insight into these problems is the goal of the united ESA - NASA mission of the SOHO spacecraft.

The spacecraft is equiped with a number of new instruments for solar observation, one of which is LASCO. This instrument monitors the solar corona above the Sun's limb in a similar way as we perceive the corona during a solar eclipse. It produces images of the corona in the visible spectrum and with distance off the Sun's center ranging from 1.1 to 32 solar radii.

In the innermost range from 1.1 to 3 solar radii observations are made at five different wavelengths which allows to deduce the distribution of important plasma parameters in the solar corona. This telescope (C1) was designed at the Max-Planck-Institut für Aeronomie, Katlenburg-Lindau, Germany and was produced in a combined effort with the Naval Research Laboratory, Washington, DC, USA.

The telescopes C2 (covering the distance range of 1.5 to 6 solar radii) and C3 (3 to 32 solar radii) were constructed by the Laboratoire d'Astronomie Spatiale, Marseille, France and Naval Research Laboratory, Washington, DC, USA, respectively. The instrument container was built by the Department of Physics and Space Research, University of Birmingham, Birmingham, England. This multinational cooperation was supervised and headed by the instrument's principal investigator Dr. Guenther Brueckner from NRL.

There is a close link between LASCO and another instrument, EIT, who share the same electronics unit through which the instruments communicate with the spacecraft.

The spacecraft SOHO was launched on 2nd Dec 1995. The LASCO-C3 telescope produced its first image on 29th Dec 1995, C2 and C1 on 26th Feb 1996 and 29th Jan 1996, respectively.