PEPSI, the
Potsdam Echelle Polarimetric and Spectroscopic Instrument, is a high-resolution
echelle spectrograph with two polarimeters to be installed on the LBT.
In the works for
many years at the Leibniz-Institute for Astrophysics Potsdam (AIP), the
spectrograph made it finally to the mountain in early July.
Three of the six
containers used to transport the spectrograph and its enclosure are seen at the
MGIO (Mount Graham International Observatory) base camp near Safford.
The spectrograph
is not mounted on the telescope (it is much too big!) Instead, it is mounted on
the first floor of the observatory inside the pier supporting the telescope.
The optical
bench, freshly installed in the coudé room inside the pier.
The light is sent
to the spectrograph through fibers which pick the light from the telescope at two permanently mounted focus units (one per LBT mirror) which have been installed
on the telescope central platform, allowing the spectrograph to be permanently
available for non-polarimetric spectroscopy. The observer will have a choice of
using fibers of three different core diameters, giving resolutions of 32,000,
120,000 and 320,000.
The PFUs (Permanent
Focus Units) feeding the spectrograph. Seen as white boxes on the bottom left and
right of this picture from last November, the left one is already installed and
the right one is being craned to position and secured to the telescope.
PEPSI will be
available for science in its spectroscopic in a year or two from now, after months
and months of reassembly and testing. You can see below some of the exciting science PEPSI will tackle.
- More information
on PEPSI on its web site.
- Members of the
LBT community, if you are interested in eventually using PEPSI, you are welcome
to read the presentation given at the recent LBTO Users' Meeting by Klaus
Strassmeier, the Principal Investigator of the project, available here.
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