Building for the 3.5M ARC (Astronomical Research Consortium) telescope - largest instrument at Apache Point
Cassegrain focus is impossible. Nasmyth focus is used instead.
The truss was recently rebuilt for this scope - the original truss and spider were not sturdy enough...built too much with a 'lightweight at all costs' approach.
Various detectors (imagers and spectrographs) sit on wheeled dollies next to the Nasmyth focus (powered up and cooled). The sole telescope operator/technician can walk to this room, change instruments, and be back in the control room in only a few minutes.
Building for the 2.5M Sloan Digital Sky Survey (SDSS) telescope. The shelter rolls away to leave the telescope (and its close-fitting wind screen) sitting in the open.
Rear of the 2.5M SDSS scope - Cassegrain focus. This is where a multi-fiber spectrograph, or multi-CCD camera is placed.
Looking from the front of the telescope. We see the close-fitting wind screen...the telescope is hidden inside.
One of many (thousands?) of precision drilled plates for the multi-fiber spectrograph. Each plate is custom fabricated for one region of the sky. Approx. 635 optical fibers are loaded by hand into a plate. On a long clear night 9 spectrograph plates can be used...over 5,500 spectra can be obtained on one night! (But it's not much fun manually inserting the fibers into the plates!)
Close up of one spectrograph plate. After all the optical fibers are inserted, the entire unit is tested (with an automated rig) to make sure each fiber is routed the correct hole.
This plate has had all fibers loaded, and is now in a cart that can be wheeled to the 2.5M SDSS telescope for rapid changeout during the next clear night.
This diagram shows the arrangement of the CCD array in the SDSS imaging camera. TDI 'drift scanning' is used to build the images...a long strip across the sky. On a night when the scope is operating in imaging mode...in the control room you can see the output image scrolling endlessly across several monitors. Lots of data!
Building for the 0.5M photometric calibration telescope that works in conjunction with the 2.5M SDSS telescope.
Carried on a mount built by DFM Engineering.
Building for the 1M telescope used by NM State University.
The alt-az fork is a truss structure.