SALT/PFIS Photographs

PFIS Assembly: Optomechanics


28 October 2004:

We took delivery of the camera in Madison and opened up the box in order to test the focus mechanism and to lift the camera onto its cradle for integration with the instrument. We took off the cover on the detector end to examine the optics. The picture below right shows the detail on the flexures on which the singlet and triplet are attached. The focus mechanism moves these two groups inside the camera barrel to adjust focus.

13 October 2004:

Alan has completed the assembly of the camera and is ready to test the image quality.

08 August 2004:

Alan has completed all of the lens cells and groups for the collimator, aligned them, and verified the back focal distance and quality of the imaging. I then made a visit to his facilities to witness an alignment demonstration and perform it myself. Below are pictures demonstrating this process.


Main collimator group is aligned with the alignment scope.

Then the field lens is put in place.

Another view of the field lens and main group.

The spacing is set between the field lens and main group and then it is adjusted to the alignment scope.

The alignment scope is repositioned to the other side and realigned with the main group.

The doublet is aligned to the scope next and the spacing set.

With the optics aligned and spaced properly, the imaging can be tested. Alan used a telescope to shine collimated light into the optics, but an autocollimation method will be used in Madison.


A microscope on a stage is placed in front of the field lens.

A telescope with a light source and interference filter shines nearly monochromatic, collimated light into the optics.

Don't forget to put the waveplate compensator in!

09 July 2004:

Alan has the collimator groups all assembled and is aligning them with the spotting scope (at far left).

24 June 2004:

To the left is a picture of the field lens assembly in an evacuated bell jar during the process of filling the coupling fluid. This is to help minimize the formation of bubbles in the fluid.

09 April 2004:

I made a visit to the Pilot Group's facility in Monrovia. Alan showed me the various lens barrels and the lenses that he has already mounted.

Left: Camera barrel with focus mechanism feedthrough.

Right: Four out of five lenses currently mounted and the salt lens. The salt lens and two lenses with sol-gel coatings are covered.

The first element in the field lens mounted in its cell. There are adjustment screws in the cell that allow for tip/tilt adjustment once it is in place within the structure.

The most recently mounted lens on the mounting table. The cell is centered up on the rotating table first with a runout probe. Then the lens is put in place and adjusted by viewing a reflection off of the top surface until it is aligned with the cell.

Left: The negative singlet, first element in the main collimator group, in its cell. The top surface is coated with sol-gel.

Right: The positive singlet, the next element in the main collimator group, in its cell. Both surfaces are coated with sol-gel.

Left: A coupling fluid expansion bladder.

Right: The focus mechanism motor.

Left: Barrels in the main collimator group showing the delrin spacers.

Right: Cell for the second field lens element. After mounting, this will be placed above the first element, and the space between filled with coupling fluid.

The mount for the collimator doublet, showing adjustment screws.

08 April 2004:

During the alignment process, Alan accidentally put a ding in the collimator's salt lens. Shown below is the lens with the new ding (note that there is an old ding that was put in by Janos). We are currently assessing the situation, but this should not affect any optical properties of PFIS as it does not extend into the clear aperture.

01 April 2004:

The below pictures show the first element bonded into its cell.

21 March 2004:

The PFIS Optomechanics were designed and will be assembled by Alan Schier of the Pilot Group. David Buckley, the Project Scientist for SALT, visited the Pilot Group and sent us some pictures.

PFIS Optics in their transport boxes:
Various cells and barrels:
Closeup of a lens mount:
The microscope lens positioning/mounting system:
XYZ measuring machine:
David Buckley holding one of the cells:
Laminar flow bench (in clean room):