The Ohio State University College of Mathematical & Physical Sciences Department of Astronomy

Attendees: Darren DePoy, Paul Byard, Jerry Mason, Pat Osmer, Tom O'Brien, Mark Derwent, Bruce Atwood, and Rick Pogge.

This report covers progress over the last 2 weeks.

Mechanical

Mark Derwent has finished detailing the welding fixtures for the upper structure of MODS. Tom and Paul are currently verifying the design against the optical path to make sure there are no unintended problems. So far things look good. Tom is detailing the multislit mask storage and insertion assembly, and when finished he will release drawings for fabrication of the system.

We have begun to take delivery of parts for the flexure control system (IR lasers and related gear), which Jen Marshall will be assembling over the next few months.

Optics

Progress at SOML has been excellent, and we are currently awaiting a progress report from REOSC on the collimator mirrors. We are still ~3-4 months from the expected delivery of the first collimator. In the meantime, we are going to be working with REOSC to determine how we will do the acceptance of the pieces.

Paul is currently working on the detailed optical design for the front-side AGW cameras, working from Tom's current mechanical design.

We have received quotes for the reflective coatings for the MODS mirrors, and are preparing requests for quote for anti-reflection coatings for lenses and for the dichroic beam splitters. We are currently considering broad-band multilayer dielectric AR coatings on the camera corrector lenses and field flatteners, and are looking at MgF₂ for the field lens (which has to work over a much wider wavelength region than the blue- and red-side optics), but will also explore more sophisticated coatings (e.g., teflon-stabilized solgel on MgF₂ as used, for example, on GMOS).

One remaining issue for MODS is a selection of baseline order blocking filters for use with the low-res red grating. Feedback from potential MODS users would be appreciated in helping define the suite of filters needed (they are individually expensive so we will have to choose carefully for the initial set).

Front-Side AGW Cameras

Chris Morgan has submitted questions to Mike Lesser and Gary Schmidt at Steward regarding the Steward Guider Cameras that are currently under consideration for use in the MODS front-side AG units. We are awaiting their replies, and Chris' report at a subsequent MODS team meeting.

Schedule and Deployment

Darren is currently drafting a fabrication and integration schedule, and a first cut at the deployment plan for MODS, now that the big picture of how things are coming together is becoming clearer. Tom and Darren will work on getting the time-and-effort estimates for various tasks updated and into the system. We should have an early (non-release) draft circulated to the team by early next week for review. This process should lead to a mechanism for detailed progress review as we continue making the transition from design and fabrication into the integration and deployment phases of the project.

Software

Rick and Jerry are starting to detail the hardware requirements for the MODS control and data-acqusition computers, since any machines we are likely to need for MODS should be purchased during the next 6-months or so. The first of the MODS Linux workstations has arrived, but we are having some hardware problems that need to be cleared up with the vendor before we can get down to installing our software onto it.

A prototype of our new Linux-based data-acquisition system was deployed with the 2-channel ANDICAM (a IR+CCD camera) at the CTIO 1.3m telescope in January, and has been in regular (nightly) operation ever since and working flawlessly. A second copy of the system is being deployed with OSIRIS when it moves to the 4.2m SOAR telescope on Cerro Pachon later this year. A version without the SOAR TCS interface module was tested at CTIO with OSIRIS in the lab in February and worked great. We have a LabView TCS simulator from the CTIO/SOAR team, and are working on the TCS interface agent for OSIRIS at this writing. Data from the performance of these deployed field systems is already providing valuable feedback for our detailed MODS software planning.