IMACS progress report no. 8 B. Bigelow 2 December 1998 Engineering Objectives for November: Status: done A. Finish preliminary slit mask fabrication development (Bruce) I.P. B. Start Prelim design of instrument structure (Bruce/Tim) late C. Finish TV guider optical design and layout (Brian/Bruce/Tim) late D. Finish prelim. design Slit Mask Handler (SMH) (Bruce) I.P. E. Start prelim. design of Disperser Server (Tim) done F. Attend GMOS laser cutter acceptance testing (11/17-11/20) Engineering Objectives for December: A. Finish solid model of SHM (Bruce) B. Finish solid models of TV guiders (Tim) C. Finish prelim. design of DS (Tim) D. Start prelim. design of L. Cam and Collim. optics (Tim) E. Identify/Contact consultants regarding TV guiders and Opto-mechanics F. Start prelim. electronics concept design (Carr/Bigelow) G. Start prelim. software concept design (Birk/Bigelow) Optics and CCD reports from Brian Sutin and Greg Burley attached. 1) Project scope, budget, and schedule We are currently planning a Preliminary Design Review for March 1999. Bruce and Tim are working to have the preliminary optical and mechanical design of the instrument (meaning functional requirements, mechanism, cell, and structure designs, and detailed solid models for all subsystems) ready for the review. We will also be reviewing the optical design, software design, and electronics designs at that time. Dave Carr will be providing some preliminary guidance for electronics based on proven concepts from the Magellan telescopes. Christoph Birk will be providing the preliminary design for IMACS software, again based on concepts developed for Magellan and Las Companas instruments. Finally, a revised budget and schedule will be generated, based on the latest versions of the mechanics, optics, electronics, and software. 2) Conceptual designs A well developed 2D design (including commercial motion stages and air-powered actuators) for the slit mask handler (SMH) is on the wall outside of Bigelow's office. The slit mask handler design is being used as a training ground for "Mechanical Desktop 3" (MD3), the Autodesk software we are using for the design of IMACS. The 3D model of the SMH is running slightly late, but is well underway. Tim has produced a MD3 model of all of the IMACS optics, as well as a parametric solid model of the instrument space frame. We will continue to add detail to the model as the various instrument sub-system designs are defined. Tim has suggested a different layout for the disperser server, and started a solid model of the Optical Support Structure (OSS), which hold the collimator, cameras, and disperser server itself. He plans to get the disperser server layout back on schedule in early December. We are moving ahead with the hybrid structure design for IMACS, which uses a monocoque for the OSS and a space frame to attach the OSS to the Magellan instrument rotator. 3) Slit masks and fabrication Bigelow and Martin Beckett (Magellan IR instruments) visited Advanced Recording Technologies (ART) as scheduled on 11/19. We were able to cut multiple slitletts in 5 different material samples (3 carbon fiber samples, aluminum, and stainless steel). The slits are in Bigelow's office for viewing. In general, the mask cutting demonstrated the feasibility of laser cutting mask material of our specifications. Regardless of which material and cutting method we ultimately choose, at least a month of optimizing the procedure will be required. 4) Electronics Preliminary specification of electronics was scheduled to start in November. This work is late and an initial electronics meeting will be held with Dave Carr in December. 5) Software No software progress scheduled or completed this month. Bigelow and Birk will be meeting this month to start the preliminary specification for the IMACS software tasks. 6) Optics Via Brian Sutin: DONE, November: 1) The long camera and collimator fabrication contract have been let to TORC. TORC had the lowest reasonable bid, and has had a considerable amount of experience with similar optics (the ESI camera, for example). 2) Preliminary research into coatings has found that Coherent will do coatings for near the budgeted costs. Other companies such as Continental optics are cheaper, but have considerably more risk. 3) The TV guide lenses have arrived. 4) A very crude thermal analysis of the collimator shows that the thermal problems are similar to the long camera's. The focus can be compensated by moving one element, which also corrects most, but not all, of the thermal scale changes. A more careful analysis is required. 5) The IMACS team has designed a procedure for minimizing the effects of mechanical flexure on the optical system. The space-frame structure will be optimized with respect to the optical image movements which cannot be corrected by the flexure compensation system. Thus the spectrograph will not be required to be inordinately stiff in order to achieve image stability. ------------------------------------------------------------------- TODO, December: 1) Order material for the direct imaging flat. Let fabrication contract? 2) Finish thermal analysis for collimator and short camera. 3) Measure TV guider lenses for principle planes. 4) Ask coating companies for detailed proposals. 5) Begin measuring, weighing, and shipping glass blanks. Coming up: 1) Start thinking about filters. 2) Melt update to collimator and/or long camera? Find final lens sizes? 3) Get cost estimate and drawing for 6.5" etalon from Queensgate. 4) Calculate image motion sensitivities. 5) Calculate alignment sensitivities. 7) Guiders and CCDs Via Greg Burley: Guider camera update (for November): 1 - Assembly of the guider camera circuit boards! Two copies of the DSP timing board, clock driver board, and signal processing board were populated and run through the reflow oven. Each pair of boards took about half a day to assemble and reflow. The last few missing parts will be put on with the rework equipment. Each of the boards has been probed for shorts and briefly powered up. One of the DSP boards was shorted, so we rebuilt it on a new pcb. The next task is to test the boards. The power supply boards have been tested previously. The next step will be to get the pci <--> dsp interface working. 2 - Assembly of the PCI interface. The add-on board is wired, populated, and ready for testing. Mosaic camera update (for November): 1 - Circuit board design. The schematics are now at v0.3, and layout of the power/utility board has started. 2 - Communications link. It looks like it will be possible to support a byte-wide link (12 twisted pairs), and a fiber interface to communicate between the controller and the host PC. The fiber interface will use a byte-serializer chip and a decoder chip at each end, and a duplex optical module ie there will be one fiber pair. The setup will use power-line jumpers so that it can be powered off if not needed. 3 - Ian and Greg visited the CCD lab at NOAO and had a good look at the 8k mosaic and the test setup for the SITe devices. It is unlikely that NOAO can test our devices, so we will have to prepare a basic setup and test dewar here. We should expect this be time-consuming. The rep from Keyence will be here on Thursday Dec 17th at 9am to show us their displacement meters. They have an interesting device which is a combination displacement sensor and 90x confocal microscope.