<IRMS mini-Study Team Meeting #3 >

Date: Tues, Sept 20, 2011
Time: 9am - 10am PDT
Location: Caltech, Cahill room 126

Participation (update as appropriate)

Attending: Matthews, Weber
Call-in: Konidaris, Simard
Unavailable: Dekany (traveling), Ellerbroek, Mobasher

Dial-in (U.S. & Canada): 866 217 1869
Conference Code: 9147077081

Agenda

  • 0900 - 0915 Optics - Nick
  • 0915 - 0930 Mechanics - Bob
  • 0930 - 0940 Science - Bahram

Minutes

  • Luc reviewed TMT interactions with CSEM concerning the CSU for IRMS. The preferred gravity orientation was discussed, but not repositioning the knife edges on the bar tips.
  • David Loop and Rich are working on the data exchange issues. For the OIWFS, the probe arm concepts will likely be shared, but the the mechanics will likely be re-worked to fit IRMS. The positioner design for IRIS is overkill for IRMS.
  • It would be good for Bob and Vlad to collaborate as much as possible on the NFIRAOS port and rotator support interfaces.
  • TMT would like Bob to inform about anything missing, incomplete, or unclear in the ICD in some form of write-up so that the ICD can later be revised accordingly.
  • Nick has released a 2nd version of the optical design memo which correctly restrains the lens edges (girdles) in order to address the mechanical issues raised with the 1st version. This design also achieves good optical performance.
    • Bob discovered a small spacing error between the field lens and the 1st fold mirror which will need to be corrected. Correcting this shouldn't effect the optical performance significantly. Bob suspended finishing the updates to the CAD model of the V2 prescription until the discovered error is corrected.
    • Keith & Bob pointed out that it may be possible to reverse the knife-edge placement on the CSU bars while keeping the CSU position the same- this could help the collimator performance with fewer changes to the collimator barrel lenses. The goal being to change as few things as possible.
  • Keith asked whether the optical performance is good enough without any changes to the camera. Nick pointed out that the camera was optimized as Harland Epps did, but that Nick's merit function is not identical to Harland's- which could result in the camera prescription change. This will be looked at again once the spacing error is corrected and the knife-edge placement effect on the collimator is studied.
  • Keith asked if we were sure that the lens materials are all available and if Nick has discussed this work with Harland. Nick intends to look into the glasses once we have confirmed the optics performance for IRMS, and that Harland would likely be contacted to discuss sources.
  • Bob has created a new rotator module support structure model based on the information provided for the IRIS support. Since IRMS' CG is significantly closer to NFIRAOS than IRIS', the hexapod structure is collapsed so that the angles are less than half of the IRIS structure. The six struts are nearly horizontal- which means large tensile forces will be exerted on the NFIRAOS structure cross-members. Some calculations/analysis will be completed to help determine if this is the best approach for IRMS.

Outstanding Actions

  • Bob to provide written feed-back on the completeness of the ICD.
  • Bob to provide Nick with the axial spacing between the extreme CSU bar knife-edge positions for consideration on the optic design changes.
  • Luc will talk to Vlad about providing more detailed SolidWorks model of NFIRAOS, including the attachment of the hexapod (may only be at the level of shells under the new NFIRAOS design)
  • Luc will look for original source material from the 2009 RfI to CSEM
  • Rich to ask David Loop for detailed SolidWorks drawing of IRIS OIWFS for evaluation in IRMS exterior envelope - Begun, in discussion with David L.
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Topic revision: r4 - 2011-09-20 - BobWeber
 
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