Mounting AGW #2 and IRTC2 at RFGB

Douglas Miller
5 March 2010

The mounting of AGW#2 and the IRTC2 with the correct orientation involves three steps:

Mounting AGW#2 onto the RFBG Rotator

  1. Set the movable part of the RFBG rotator such that the opening of the cable wrap is straight up. The value of rotator position in is not important so just input the number in to the MCSPU needed to place the cable wrap opening up.
  2. Mount the AGW #2 such that the Cooling, Power and Fiber interface panel is placed at 5:00 o’clock. This panel will be 30 degrees counter-clockwise from straight down. The AIP guider and wavefront sensor (w) unit will be to the upper right at 2:00 o’clock and the Arcetri Pyramid (W) sensor will be to the lower left at 8:00 o’clock. Depending on the bolt hole pattern in the rotator, it may not be possible to mount the AGw unit at exactly 30 degrees from down so choose the bolt holes that place it the closest to 30 degrees. This offset can be corrected in software (PCS).

Mounting the IRTC2 onto AGW#2

  1. Keep the rotator in the same position as was used for mounting the AGW above.
  2. Mount the IRTC2 and its interface plate to the AGW #2 such that the large silver label that says “IRTC 2” is located at 8:00 o’clock.
    1. There are two mounting pins connected to the IRTC interface plate, a conical pin pressed in and a thermal expansion pin bolted to the interface plate. These need to be moved from their current locations on the IRTC interface plate by 90 degrees. There are only two possible locations for the Thermal pin and two for the conical pin, so remove them from their current locations and put each in the other possible location. (But, beware that this may have been done in advance when IRTC2 was mated to AGW2 in the lab (week of 01-March-2010).
    2. In an email from Italo:
      Dear Doug,
      You are right about the thermal pins: it is simply
      held by 4 screws so it is very easy to remove it.
      The other pin, the conical one, has been mounted
      by the guys at the telescope few second before mounting 
      the IRTC on AGW. Joar was there supervising the operation
      so he should be aware of everything. This pin is hammered
      into its hole by means of a "soft" hammer in order to 
      preserve the reference surface, the front one. This pin
      should easily be removed hammering it on the back through
      its hole which is a through hole. I guess that to remove it is
      better to use a standard ("hard") hammer and a single well
      done shot should be enough.
    3. I put labels on the IRTC interface plate to point to the location of the mounting pins needed for mounting at Right Front Bent Gregorian as well as the location of the AGw Power, Cooling and Fiber patch panel and the position of the opening of the Cable Wrap.
    4. Once the pins have been moved there are only two possible mounting orientations for the IRTC 180 degrees apart. Choose the one with the “IRTC 2” label at 8:00 o’clock.
    5. Note: check that the dichroic mounted on the “backside” of the IRTC interface plate will be reflecting light into the Arcetri Pyramid Sensor, which should be located at 8:00 o’clock.


Above is an image of how the cable wrap and IRTC should look once mounted at Right Front Bent Gregorian, and the location to the Power, Cooling and Fiber patch panel of the AGw #2 unit.

If you have any question or comments, please email me. If there are questions during installation, you can reach me on my cell phone at 609-8663


-- DougMiller - 06 Mar 2010
Topic revision: r2 - 08 Mar 2010, JohnHill
This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding Foswiki? Send feedback