TSU 2-m AUTOMATIC SPECTROSCOPIC TELESCOPE PROJECT Monthly Report for July, 2000 This monthly report for the TSU 2-m AST project, now liberated from the hubris of NASA Code S, covers the calendar month of July, 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--II) covers the status of various tasks in the schedule; and a third part (V) gives highlights for July. During July, 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. Allen Keel continued doing projects related to the control system as a summer student, and Kenneth McDavis assisted on several projects involved in perfecting the telescope. I. HIGHLIGHTS FOR THE PAST MONTH During July, 2000, we said we expected to do the following things [with steps taken then in brackets]: (1) to colimate the primary mirror and achieve first light with it, [We devised a method for colimating the mirror that worked well enough to align the axis to about 1.75 arcmin. It showed that we will have to remake the axial hard points, however, because the motors were not strong enough to move them reliably. We were unable to observe any stars because of the weather during the rainy season in southern Arizona.] (2) to obtain images of the north star sufficient to begin testing the optical figure of the primary mirror and assess how well its supports work, [We wuz clouded out.] (3) to find stars with the evolving control system and perform the first tracking tests with the telescope, [It was too cloudy to attempt this in July.] (4) to assess the degree to which the telescope mount deviates from alignment in terms of perpendicularity of its axes, [We measured this as 18 arcsec.] (5) to identify students to make mathematical models of the secondary-mirror cell and telescope mount and devise algorithms for moving the secondary with its drive motors and for correcting pointing for imperfections in the mount, [We have talked with Kenneth McDavis and Paul Strong about this project.] (6) to continue procuring the material and services for constructing the camera for the spectrograph with the aid of Harland Epps [These tasks are progressing steadily]. II. ENCLOSURES Boyd has finished connecting the wires into the telescope to the building and enclosed them in a special cable run. We deferred rewiring the oil pump indifinitely and are instead using a heavy extension cord to connect it to the power, which works well for testing the telescope. We also have continued working with Sierrita Mining about further details of how to modify the control/spectrograph buildings and expect them to start work in August. III. CONTROL SYSTEM During a 1-week work session in Arizona in July, Williamson ran the telescope extensively under computer control and remeasured the slippage of the drives. The drives seemed to slip even less at the observatory than in the assembly building, which suggests they were better aligned and had achieved a stability from being run longer. He also reran a program that records the values of all the encoders on each axis for assessing the stability of the positions derived and how much the drive wheels may be slipping, as well as an extensive series of tests to determine how to choose the PID constants for the drive to keep the motors stable. We now have a pretty good idea of the stability of the tilt axis, since it has a functioning absolute encoder. Unfortunately we broke the wire coupling the absolute encoder to the azimuth axis and could not use it for similar tests in azimuth. Williamson has devised a scheme for adding friction to the axes of the drive simulator in Nashville to make the demands similar to those encountered in the actual telescope. This will make our control-system tests at TSU much more realistic. Keel has been investigating the use of guide stars with the acquisition/guiding camera we are using in the telescope. He has determined the approximate limiting magnitude of the guide camera by using images Williamson took with a small camera lens (appx. 15th mag for an 8-sec exposure). He has also used randomly selected fields with the digitized Palomar Sky Survey at STScI to estimate the frequency of fields that will contain a usable guide star. He should finish a report on this work in August. IV. SPECTROGRAPH CAMERA Having contracted with Harland Epps to oversee development of the spectrograph camera, we have continued procuring the parts and services for it with his help and supervision. Busby has spearheaded this effort. Using the bidding documents Epps drew up, we have established contracts for obtaining materials for the lenses (CaF2 and optical glass blanksr), which are proceeding, for design of the cell to hold the lenses, and for grinding and polishing the lenses. The contract for coating the lenses to minimize is being rebid but is expected to be resolved by the end of the month. Task 208-210: Mark Wells has made significant progress on manufacturing these mounts and expects to have most of the initial work on them done by the end of July. We have had Marlyn Krebs make some of the smaller parts in Nashville, and these are finished. We still have to produce shop drawings for the device to position the fibers at the focus of the collimator. V. HIGHLIGHTS FOR THE NEXT MONTH During August, 2000, we will suspend detailed testing of the telescope on site in Arizona, because of the weather and resume tests in September. We plan to use the month instead to catch up on tasks that can be done in Nashville, specifically (1) rebuilding the axial hard points by replacing the motors with manual screws and to build better attachments for the springs to hold the mirror down to the hard points, (2) obtaining the computer to use in the telescope, (3) archiving the drawings of the telescope and its enclosure, (4) beginning to write the actual computer program to control the acquisition/guide camera, (5) starting to modify the building for the spectrograph and local contol/utility room, (6) finishing setting up the spare drive tractor, (7) continuing to procure the material and services for constructing the camera for the spectrograph with the aid of Harland Epps, and (8) beginning to take delivery of most of the parts of the mounts for the spectrograph optics (mirrors and gratings) and to start integrating them mechanically.