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

Attendees: Ross Zhelemn, Tom O'Brien, Mark Derwent, Bruce Atwood, Dan Pappalardo, Ray Gonzalez, Jason Eastman, & Rick Pogge

MODS Optics

Ross reported on progress at SOML regarding CMM measurements of the red corrector lens parent. Ross has requested data on the reference ball positions to help assess the systematic and random errors in the CMM surface map reconstructions after stitching. This will help us quantitatively establish when we have reached the limits of the CMM measurements so we can judge when this stage should end and we should proceed to polishing and optical testing.

Blue corrector lens #2 has been installed in the camera and restored to the same position as "alignment" for Blue Corrector Lens #1. The position was reproduced to <1 milliRadian, which validates our alignment process, and means that we can dismantle the cameras and expect them to be extremely close to alignment on reassembly (with all due care taken in both processes).

First light analysis of the lens was excellent and Ross proceeded immediately to imaging tests, which showed that this second lens is also performing to specification. It is being removed from the lens cell later this week and it and Blue Lens #1 will be prepped for packing and shipment to ZC&R for AR coating.

Ross and Tom are redesigning the shipping packaging for the camera primary mirrors and collimator lenses, and will be prepping the red mirrors for shipment to NTFL for protected silver coating later this month.

MODS Electronics

Dan has been making progress on the conceptual design of the calibration lamp power box, with some more work to be done. There was some discussion at this meeting of the merits of making this box the housing for the IMCS laser, and to make it standalone, having its own internal WAGO interface for lamp control, instead of making it just an outrigger of the instrument electronics boxes (IEBs). The action item for Dan is to assess the power requirements of this box, particularly whether it will require active cooling to satisfy the thermal spec. Dan will add the IMCS IR laser package and WAGO interfaces to his on-going work to measure the power budget analysis of the pen-ray and QTH lamp power supplies and give us an answer by next meeting.

In other electronics work, Dan has finished the AGW/Calibration Tower hardware interlock and cable and handed these off to Ray for testing with IEB#1 in the lab. The hardware interlocked worked fine, but the testing found bugs in the software interlock. Ray will continue testing of this critical item (note: the test is done with the working AGW and Calibration Tower mechanisms in the lab, but setup separately on the floor so as to not physically overlap like they would on-instrument).

MODS CCDs

Bruce reports that the mechanical sample of the e2v 3x8K CCD has arrived intact and looks great. It arrived in the most elaborate metal "Barbie coffin" that Bruce has seen since the days of the old Tektronics CCDs. For some reason, e2v only installed about 80% of the wirebonds on both corners, but this presents no problem (we just wonder why they stopped at 80%).