TSU 2-m AUTOMATIC SPECTROSCOPIC TELESCOPE PROJECT Monthly Report for April, 2000 This monthly report for the TSU 2-m AST project covers the calendar month of April, 2000. The first part of the report (I) discusses what we did with the expected highlights identified in last month's report; the second section (II--IX) covers the status of various tasks in the schedule; and a third part (X) gives highlights for May. During April, 2000, we continued to have one part-time employee (Mike Williamson) working at TSU on the telescope program, in computer programming and electronic instrumentation, in addition to M. Krebs and M. Wells, who provide machining work at their private shops. We arranged to use Allen Keel as a summer student doing projects related to the control system. I. HIGHLIGHTS FOR THE PAST MONTH During April, 2000, we said we expected to do the following things [with steps taken then in brackets]: (1) to finish all testing of the telescope in Nashville and prepare it for shipment to Arizona, [We have finished all these tests as explained in III below and have started disassembling the telescope and making the modifications to it that had to await disassembly.] (2) to make the modifications of the oil bearings when the telescope is partially disassembled, [These are deferred to May, since they require an almost complete mechanical disassembly of the telescope.] (3) to continue writing the telescope control software and get it running well enough on the simulator and actual telescope to begin tests of acquiring and tracking stars during the month after the telescope is installed at its site, [We have done a great deal of this; see VI below] (4) to arrange with Bob Leach for actual delivery of the CCD dewar and controller (Tasks 145-150), [Leach has informed us that the electronics for the CCD detector are built, the cryogenics are in hand, and parts are being machined to integrate the cryogenics with the CCD. He expects delivery around the first week in June.] (5) to receive specifications from Epps for the glass for the lenses of the spectrograph camera and begin procuring that glass, and to get Epps to start drawing up the specifications for a contract for the mechanical cell for the camera lens, [We have done this; see VII below.] and (7) to finish defining Jeff Hall's role in the data handling system, define the system requirements for him, and get him started on actually modifying his software for us. [These tasks have slipped somewhat because Fekel was observing for two weeks, but we have done the first two of them; see IX below.] II. ENCLOSURES We completed plans for modifying and insulating the buildings for the spectrograph (Task63), obtained a bid for Sierrita Mining to do the work (Task 64), probably this summer, and wrote a purchase requisition for the contract for them to do it (Task 64). Tasks 66&67) will be done as part of this work or folded into Task 60 at about the same time. III. MECHANICAL INTEGRATION This phase of the project is essentially complete. We finished all of the tasks related to a final assembly of the telescope, finished all the mechanical tests we agreed to do at our meeting with you in October, and finished all the mechanical tests that Marshall wanted to do. Of the tasks remaining from last month, we have finished Tasks 75&95 relating to assembly of the telescope, finished Tasks 100&102 relating to the auxillary oil-return system, finished task 107, finishing the mirror-washing dam. We had to wait to do some of these tasks until we were taking the telescope apart for shipment to Arizona, so they necessarily have been delayed. The only tasks remaining are also in this category, namely Task 83, insulation of the telescope (which is about 90% finished) and Task 104, a contingency for the oil bearings, which involves adjusting the seals that retain the oil coming out of them. IV. MIRROR TESTING Marshall has finished running all the optical tests they agreed to do on the primary mirror. The more sophisticated of these were inconclusive, probably for two reasons. First, the tolerances on adjustment of the test equipment were very tight and difficult to achieve with the optical mounts available for the tests. Second, the null lens that Marshall used was constructed for the wrong focal length. Furthermore, Marshall has never produced a successful null lens with the techniques used to make this one, as their optical engineers related. However, Marshall did make some less precise measurements with a Ronchi grating that showed the primary mirror is not appreciably distorted by its mounting and confirm the more stringent tests with stars that Robert Parks did on this mirror (we presented you a copy of his report in June). As part of these tests, Marshall accurately measured the focal length of the primary mirror and found it is about 2 inches shorter than Torus Optics measured mechanically (and, incidently, almost exactly the same as the original specification for the mirror). This revised focal length will require us to move the secondary mirror about 1.30 inches closer to the primary, and we have designed a set of shims to do this. We will also cut down the stand for the instrument head by a similar amount to preserve the best focus, since this will be easy to do now that the telecope is disassembled. We still have a test of the secondary mirror designed to determine how much its mounting (glueing it to a 2-inch stud through a hole in the center) distorts its shape. This test is probably going to be in early May, having been delayed by problems designing, making, obtaining, and setting up the equipment to run it. We certainly appreciate the diligence and good humor of the engineers at Marshall who are conducting these optical tests. V. SET TELESCOPE UP AT SITE Having finished all the tests we agreed with you and Marshall to do before shipping the telescope to Arizona, we began disassembling the telescope and putting it on pallets in the last week of April. This work is about 60% finished as of 1 May. We certify that the telescope passed all the mechanical tests we proposed to do in the set of formal shipping criteria we gave you in October. Busby has obtained permission from the University to use the quote from Sierrita Mining (see last month's report) for transporting the telescope from Nashville to Arizona, staging the parts into the observatory, and assisting TSU personnel in assembling it. VI. CONTROL SYSTEM Williamson has continued integrating the motion-control programs to run the basic motions of the telescope (tracking and slewing) and has completed them to the point of running the telescope with these programs. He has integrated the positions from incremental encoders, time from the GPS card, and positions from the low-resolution absolute encoders, all latched simultaneously with a signal from the motion controller, into the basic software that calculates instanteneous position on the sky. We have run this program in the telescope to determine that it points the telescope in roughly the right direction and that it drives the telescope at roughly the right rates for the position it's pointed. Further, precise tests must necessarily wait until we have the telescope set up at the observatory and exposed to stars. It is particularly important for setting the telescope up to have access to the north star, which is the easiest way to determine the zero points of the axes and to do the initial alignment of the optics. As part of this work, we have replaced the Nextmove motion-control board (an ISA device) with a Galil stand-alone controller having communication through a serial line. This device is much more reliable, keeps track of a much wider range of angular position (an annoying limitation with the Nextmove), and requires a much simpler, more reliable program to run it in the telescope-control computer. VII. SPECTROGRAPH CAMERA We have contracted with Harland Epps to oversee development of the spectrograph camera. He has drawn up for us documents for procuring all the materials and services for constructing this camera so we can either bid them out or botain them through sole-source contracts. These documents cover (1) obtaining the materials for the lenses (CaF2 and optical glass blanks, along with precise measurments of the indices of refraction of the actual glass for making the final design of the lens and pieces of the glass for coating tests), (2) contracting with an optical shop to make the lenses to his final specifications, (3) contracting for coating the lenses to minimize reflections of the wavelength range we intend to use, (4) contracting with a specialist firm (which he's used before) to design a mechanical cell for the lens, and (5) contracting to build the cell. Task 208-210: Design and manufacture mounts for optical elements: We have finished shop drawings for the mounts for the echelle grating, cross-dispersion grating, and the two reimaging mirrors discussed last month and done a detailed solid model of the device for positioning the optical fibers at the input of the spectrograph. Some of the material for these mounts was delivered in April with the bulk expected in early May. VIII. SMALL SYSTEMS & CALIBRATION We have finished Tasks 245-250, a bunch of minor jobs related to the instriment head and baffling system. Task 259: Build the pick-off mirror. Mark Wells ran into problems with getting the pickoff mirror plated and has decided instead to get it polished by a specialist he found in Huntsville who has polished many metal mirrors for NASA. IX. DATA-HANDLING SYSTEM Fekel continues to work with Jeff Hall on defining the requirements of the data- handling/reduction system that Hall will write for us as a modification of his existing software. We defined and sent system requirements to Hall in April. X. HIGHLIGHTS FOR THE NEXT MONTH During May, 2000, we expect (1) to finish preparing the telescope for shipment to Arizona, (2) to finish the modifications of the oil bearings, (3) to continue writing the telescope control software, specifically preparing it for supporting Tasks 172, 175, and 177, (4) to arrange with Bob Leach for actual delivery of the CCD dewar and controller (Tasks 145-150), (5) to finish the paperwork for procuring the material and services for constructing the camera for the spectrograph, and (6) to finish contracting with Jeff Hall to write the data reduction and handling system.