IMACS progress report no. 14 B. Bigelow 7 June 1999 Mechanics Objectives for May: Status: Done A. Set and distribute revised schedule to IMACS team (BB/AD) Done B. Set revised budget (BB/AD) IP C. Continue mask cutting development (BB) Re-sched D. Start Disperser Server final design (TB) IP E. Start Mask Server final design (BB) Done F. Complete Dewar prelim design (GL) IP G. Start motion stage timing and electronics requirements (BB/TB) IP H. Continue final subsystem specifications (BB/TB) Mechanics Objectives for June: A. Continue mask cutting development (BB) B. Continue mask server detail design (BB) C. Complete filter server prototype design (TB/MP) D. Start filter server final design (TB) E. Start searches for mech. eng. and machinist (BB) F. Finalize l-cam and coll. mech. design plans (BB/TB) G. Complete dewar mech. design (Luppino) H. Start dewar prototype fabrication (Luppino) I. Order Physik Instrumente (PI) flexure control stage (BB) I) Project scope, budget, and schedule The IMACS project response to the PDR report was presented to the Las Companas Observatory Committee and the Magellan SAC in May. The PDR report and response are both posted on the IMACS website in PDF and PS file formats. As suggested by the PDR committee, we are looking into the possibility of hiring and additional mechanical engineer, as well as moving forward with the planned hire of an additional machinist/instrument builder. Design plans for the camera and collimator mechanics are being reviewed in light of the possible new hire. Revised budgets and schedules were completed following the PDR. The main instrument schedule is now posted on the door to my office. I can provide detailed or summary copies as necessary. Please let me know if you would like one. The instrument budget has been presented to the Observatory, but will not be distributed in detail form. The total estimated cost, including contingency, is approximately $5 million. A contracting drafter, Mary Poteete, will be taking on some of the IMACS drafting work, starting in June. Mary is a former employee of the Lick Obs. labs and is an experienced AutoCAD user. Mary visited SBS last week for an introduction to project, and to work out details for passing files between SBS and her office in Watsonville. Check the IMACS website (www.ociw.edu/~bigelow/imacs/index.html) for new pagess on slit-mask fabrication and optics, as well as additions to the project contributors list. II) Mechanics Bruce: Following the concerns from the PDR committee about the feasibility of laser-cut composite slit masks, additional mask and cutting development is underway. Full-size aluminum masks, fabricated using metal spinning, have been completed and delivered. We will be checking the masks for performance against the specifications in June. Images of the masks and their fabrication are posted on the IMACS website. Additional samples of 2-ply, 2 x 2 twill carbon fiber (CF) composite have also been delivered. CF, aluminum, and stainless steel samples will be used for additional laser cutting tests in June. Detail design of the Slit Mask Server (SMS) started in May and will continue through October. Tim: Reviewed documents from Alan Schier concerning the optomechanical design of the long camera and collimator. A list of additional calculations required has been produced. It was decided that we would produce a large prototype lens cell, in order to test the adhesive mounting scheme planned for the IMACS glass elements. I began to try and sort out some of the subsystem specification, more specifically the motion control stages required, and the recommended implementation of incremental encoders on several of the stages. I attending a training course for ANSYS on May 18 - 20. I would feel quite comfortable doing any required FEA analysis now using ANSYS. I have completed the filter slide mechanism solid models and am putting together a package to give to Mary Poteete for production of final manufacturing drawings. III) Electronics No electronics work planned for May or June. IV) Software Christoph: 1) I am working on a 1st draft version of the IMACS mechanical GUI. 2) Guide star catalog: I contacted USNO and ordered a copy of the USNO-SA2.0 catalog (54e6 stars, GSC has 15e6 stars only :-). V) Optics Note that images of the IMACS imaging mirror and dewar test window are posted on the website. Brian: DONE, May: 1) I added the ADC to the telescope CTE calculation. The effect was slightly against the rest of the effects. The final plate scale CTE was 7.94 ppm/C. 2) Initial results from the Coherent coating designs for the collimator and long camera arrived. They average about 0.95% per surface. They have received some feedback, and are doing another iteration. 3) A ghost analysis was completed which covers ghosts generated by two surface reflections. The results are available from Brian. Conclusions: Reducing the reflectivity of the back of the mask (here assumed to be 25%) is important. The back of the mask should have high scattering. Good coatings on the field lens will reduce stray light from the dome. Missing: light from the dome reflected off of the back of the ADC. This could be one of the worst sources of stray light. There are no show stoppers. 4) The direct imaging mirror has been sent to Newport Thin Films for coating. ------------------------------------------------------------------- TODO, June: 1) Ponder about Shack-Hartman alignment systems 2) Set up system for taking ANSYS flexure output and returning optical performance degradation. 3) Baffle analysis 4) Compare Sol-Gel to dielectric coatings VI) Detector Systems Greg/Ian: Detector systems progress (May 1999) ==================================== 1 - GB finished the circuit board layout for the PCI interface board, which will be sent out for fabrication this week. The blank boards are normally ready in three weeks. 2 - Six grade_1 EEV CCDs have been ordered for the first round of guider cameras. We've ordered the devices with the standard package. 3 - GB has been revising the guider prototype board layouts to include the modifications found in the initial testing (see last months report). So far, the boards which are ready to be sent for fabrication are the DSP timing board, the signal processing board, the power supply board, and the backplane board. 4 - Purchase reqs have been submitted for the outstanding parts needed to make twenty guider cameras. These are the high value parts (DSP, DC-DC converters, ADC, DAC ... ) which we ordered only in small quantities for the prototype. 5 - We have hired a summer student who will assemble the electronics for the first set of six guider cameras. He will be here from about the beginning of July through mid-September. 6 - We have put together an estimated schedule for the completion of the focal plane array for IMACS 8k x 8k science array 7 - Guide CCDs have been added to the 8k x 8k focal plane array. These are front-illuminated 2560 x 512 pixel devices. They will be controlled by a single set of science electronics feeding a separate PCI interface card.