FTS Assembly

In August 2010, FTS-2 breadboard was installed on a thick breadboard table, and held in position with clamps and straps. The optical 'towers' were hoisted into position and lined up with the locating plates on the breadboard. The pickoff mirror support rails were lowered into position using the hoist.

Once the FTS framework components were in place, the moving mirror assembly was aligned using a reference corner-cube and an alignment telescope. The moving mirror unit was installed on the translation stage, and then the beamsplitter framework was installed. The FTS was then convered for the wait until the alignment campaign in September.

CMM setup

In September, a Faro Platiunum 12' portable CMM arm was used to align the internal FTS optics. An additional breadboard 'outrigger' was used to mount the arm rigidly to the FTS-2 instrument. The overhead crane was used with the lifting jig to suspend the FTS during the levelling procedure.

Line Source and IR Tests

A VDI 320 GHz line source was placed at the input image plane, and a HDPE lense reimaged the output onto a Spectrum Detector pyro in order to measure the interferogram quality.

Hoisting the FTS

FTS-2 was temporarily hoisted over the right Nasmyth platform and onto the SCUBA-2 lift using the JCMT overhead crane and a hydraulic attachment, which was connected to a lifting jig to balance the system while being suspended. The jig had to be modified to prevent the FTS from tipping over as a result of the higher than expected centre of gravity and unstable chain arrangement.

Mounting the FTS

Once the lifting framework was modified to keep the instrument stable, FTS-2 was hoisted onto the N1 mirror support structure outside the left elevation bearing tube, overtop SCUBA-2. The levelling feet under the instrument were adjusted to level the instrument and ensure the load was equally distributed, and 'nudger' turnbuckles were used to position the instrument horizontally.

Mounting Videos

Some videos of FTS-2 installed, as seen without the JCMT membrane in the way:

• JCMT membrane being retracted
• First lift of the FTS-2 instrument
• The JCMT dish while the FTS is being hoisted
• The JCMT overhead crane in action
• Carefully taking the load off the FTS-2 feet
• The JCMT secondary mirror unit, and FTS-2 mounted
• FTS-2 and SCUBA-2 seen from the front of the telescope

Please send any comments or questions to

SCUBA-2 FTS Group Physics Department University of Lethbridge 4401 University Drive Lethbridge, Alberta T1K 3M4 Phone: (403) 329-2771 Fax: (403) 329-2057