The asteroid 1646 Rosseland is named in honor of the Norwegian astronomer Svein Rosseland.
It was discovered on 19 January 1939 by Y. Väisälä at the Turku Observatory or The Iso-Heikkilä Observatory in the very south of Finland.

Rosseland contributed strongly to the University of Oslo getting its own Department for Theoretical Astrophysics and it was built with the help of funds from Rockefeller Foundation in the USA in 1934. Now called Rosseland's House. In 1950, he contributed to having the Solar-Observatory built at Harestua outside Oslo.

Important parameters in Stellar Astrophysics are Rosseland- and Planck-Averaged Opacities

The lunar crater Rosseland is also named after him.

https://en.wikipedia.org/wiki/Svein_Rosseland

Sun distance (au): 2.10 Mag. 15.7

Time: 18:13UT 2011-01-02 Exp.43 x 15sec
Telescope 0.35m f/11.4 with AP7 CCD 1.23"/pix Paramount GT-1100S
Odd Trondal Obs.code 238. Oslo Norway