SALT/PFIS Photographs

Optics: Fold Flat


12 August 2004:

We test fit the fold mirror into its support structure. At the top of the fold mirror structure can be seen the mount for the double-sided flat, which will be used for the alignment of PFIS to SALT upon mounting on the telescope.

12 July 2004:

Mike did a fit-check of the flexure mounts on the fold mirror. The three trapezoidal pads will mount to the structure and adjustable screws will push against the three mount pads for tip/tilt adjustment of the fold mirror. The bar across the mirror is a safety bar with grips on each side that could catch the mirror in the unlikely event that it were to become loose or unglued.

09 July 2004:

Today, we removed the jig plate from the mirror and examined the mount blocks.

07 July 2004:

Today, Mike and I glued the mirror mounts to the back of the fold flat. The mounts are invar blocks with their mirror interface sides sandblasted and the other surfaces painted black. We used the 3M DP-460NS two-part epoxy. The jig would allow us to place the blocks accurately, with thin shims underneath to control the thickness of the epoxy layer. Tension bars were screwed in to provide pressure during curing.

Below are pictures of the process.


Fold flat - mirrored side down

Jigging plate on top of mirror

Closeup of mount block alignment hole with shims in place

Application of epoxy

Epoxy in place

Mount block inserted with tension bar screwed in

Back mount blocks in place with flexure

Closeup of mount block in place with positioning screws

Waiting for epoxy to cure

22 May 2003:

The fold flat mirror has returned. It was coated at Lawrence Livermore National Laboratory.

04 November 2002:

Here is the PFIS folding flat, uncoated. Only the front surface is polished, hence the color. Physical size: 270 x 195 x 25 mm. It has been shipped to South Africa to join a lot of mirrors to be coated.