I have now had 3 runs on this telescope, it is very cool and actually quite easy to use (link).
Where it is
"The Feed" is housed in the same building as the 2.1 meter telescope - it can be used either on it's own or coupled with the 2.1 meter - I use it on it's own.
What it does
The Feed is a spectrograph which means that it splits light from stars into the pretty rainbow of colors (like with a prism) so I can look at specific colors. I will post pictures of what I mean soon.
Oh, and it is a "coude" type spectrograph.
The big directional mirror is under the shed
Here is the first part (2.5 steps) of the light path in pictures So the light comes down, hits the main mirror (which is usually not oriented that direction), then goes across the street to the mirror in the tower then goes back down through the tube into the building
With the mirror door on the tower open :) With Ginny:
The main light-collecting mirror is really quite large...
Part (4) Then it bounces to this contraption which has a guiding camera and a slit for the light to go into a big room.
Once through the slit, the room it goes into houses several mirrors, but I have only used one configuration which I shall illustrate here.
(5) The light goes through this shutter (Ginny provided for scale) down to the "long collimating mirror"
"Collimating" the light means to bounce it off the mirror in such a way that all the light wave are straight, not curved anymore from hitting curvey mirrors.
(6) After hitting the collimating mirror, the light bounces back up to the diffraction grating
The diffraction grating is kind of akin to a prism in that it separates the different wavelengths of light - you can see it happening even in the picture.
(7) The newly diffracted light then goes through the blue corrector plate (which adjusts the light somehow)
(8) After the corrector plate, it bounces off of this flat mirror (behind which is the CCD chip)
(9) It then bounces off of the concave mirror shown here which will focus the diffracted starlight onto the CCD chip
(10) The CCD (charge-coupled device) chip (like a digital camera) is housed in a silver "dewar" which is cooled via liquid nitrogen (temp about -320 deg F). In this picture, I'm filling the dewar
The reason there is "steam" coming out of it is that there is a little bit of venting going on and the liquid nitrogen is so cold that it instantly condenses water in the air so it looks much more billowy when it is humid (it's been rather dry here).
Connected to the back of the dewar are a bunch of cables, many of which go to that golden box which is connected to a computer that interprets the data and spits it out for me to see.
My CCD is 2048 x 2048 pixels, but I only get data on 100 of the columns (that way I don't have to read out the entire chip which would take time).
So that is the telescope itself, now to my actual observing procedure for using the Coudé Feed.