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Department of Astronomy

MODS Team Progress Report
2004 January 7

Attendees: Jen Marshall, Chris Morgan, Darren DePoy, Jerry Mason, Bruce Atwood, Ed Teiga, Ralph Belville, Tom O'Brien, Paul Byard, Mark Derwent, & Rick Pogge

Optics

Paul Byard reports that REOSC delivered the last 2 collimator mirrors this week, so we now have all 4 MODS collimators (for both channels of MODS1 and MODS2) in hand. The packing job was much better than last time, and the pieces arrives safely. They are being stored in sealed containers until we can get them coated later this year.

The two red-channel field flatteners (for MODS1 and MODS2) are reported to be done and about to be shipped to us from SOML.

The remaining optics to be delivered are as follows:

  1. Blue Camera Corrector Lenses. Status: polishing in progress at SOML
  2. Red Camera Corrector Lenses. Status: rough figuring about to begin
  3. Dichroics. Status: need to finalize design and send out request for quotes.
  4. Pupil Imager Lenses (for the calibration system). Status: Need to finalize the design and request fabrication quotes.

Structure

Mark Derwent reports that progress on the first MODS upper structure at Indian Creek Fabricators has been excellent. He communicates with the lead person out there about daily. They've made some good suggestions about how to fabricate some of the trickier connections (where multiple struts come together), and we should see the first structure within a month or so.

Mark has sent out a bid package for the fabrication of the MODS cart. The package includes suggestions from John Hill regarding eyebolt locations for lifting MODS. The cart has turned out to be a bigger job than originally expected. One of the issues was the detailed clearances in the OSU shop when we rig the cart for flexure testing. We can swing the cart from horizon-pointing to nadir-pointing with no problems (provided we pick the right part of the shop that misses some airconditioning stuff), but we cannot continue to swing it through a full 180-degrees to the opposite horizon-pointing position because of interference with the shop's large "garage door". At most we can get about 30-degrees from nadir, or 120 degrees full motion. Still, the cart design is now complete and will meet all of our fabrication, storage/handling, and flexure testing needs.

Mechanical Fabrication & Design

We have taken delivery of the collimator strut tapers from EMS (Elyria Metal Spinning). We're waiting for the McPherson Lab freight elevator to get fixed so we can get them into the shop and open the boxes.

Mark has taken delivery of the parts for the MODS darkslide from Columbus Machine Works, and has assembled the first darkslide. He rigged it up with one of the on-the-shelf stepper motors and a Computmotor controller we had on hand. Without any fine tuning he has it working cycling through open/closed positions. To demostrate this, here's a little 13-second

QuickTime Movie (4.5Mb)
showing it do its thing. The drive is a simple single-motor drive with a double belt loop. The opposed darkslide doors run in a machined Delrin track. The closure point is scissored to ensure a good light seal. The speed of open/closed is simply what we set it to for the tests. The closing force is actually pretty small (i.e., it is not a guillotine), but it'll be tuned for safety in the final system.

Guide Cameras

We have not yet received the guide camera system from Steward Observatory, but have all the optics we need to build the imaging optics for them when they arrive.

MODS Progress Review - 2004 April 22 & 23

A MODS Progress Review will be held on 2004 April 22 & 23, with Joar Brynnel, Mark Wagner, and Tim Axelrod from LBTPO attending. We'll have more details about schedule later.

With Winter Quarter now under way, we expect to meet every week or so (travel and other events permitting) every Wednesday at 2pm in the Conference Room.
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