The DECam prime focus cage is raised into position in the top ring.

[Ptah]

http://www.noao.edu/news/2012/decam-install.php

The DECam prime focus cage is raised into position in the top ring



With the Blanco 4-m telescope locked in a vertical position and the old prime focus cage removed,
the new DECam prime focus cage is winched up to the top end to be installed. The new cage is
braced by the yellow “strongbacks” and in the picture can be seen nearly in position and
surrounded by the installation team standing on custom work platforms.

-----------------------------------------



http://en.wikipedia.org/wiki/The_Dark_Energy_Survey#Overview

The Dark Energy Survey will investigate the dynamics of the universe and the large-scale structure
using four techniques. The first one consists in the observation of the light curve of Type Ia supernova.
According to the accepted theory, a Type Ia supernova is an explosion of a white dwarf star that orbits
around a companion star, caused by the accretion of mass from the companion star, which makes it unstable,
starting, as a consequence, a gigantic thermonuclear explosion.[5] For cosmology, these events are important
because they are very bright, which allows astronomers to detect them at very large distance, and their
luminosity distance (there are more than one definition of distance in cosmology and they are not equivalent.
Consequently, it is important to specify what kind of distance you are measuring) can be inferred by the
observation of their light curves. Finally, the standard model of cosmology, which is based on some
assumptions that includes the validity of General Relativity and the large scale homogeneity and isotropy
of our universe, predicts that astronomers can constrain the properties of the expansion of the universe
based on the observation of the luminosity distance and the redshift from far away type IA supernova.