TSU 2-m AUTOMATIC SPECTROSCOPIC TELESCOPE PROJECT Monthly Report for December, 1999 This monthly report for the TSU 2-m AST project covers the calendar month of December, 1999. 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--VII) covers the status of various tasks in the schedule; and a third part (VIII) gives highlights for January. During December, 1999, 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. December was not an especially productive month, with the university shutdown between 24 December and 3 January and with preparations for Christmas distracting us before that. Eaton and Williamson both took vacation in late December. I. HIGHLIGHTS FOR THE PAST MONTH During December, 1999, we said we expected to do the following things [with steps taken then in brackets]: (1) To finish testing the telescope drive enough to support mirror/mechanical tests planned by MSFC in January, [We set up two control programs that allow us to move the telescope in both axes to position it accurately for tests of both repeatability and tracking smoothness. We have used them in tests of the drive tractors and for adjustment of the drive-tractor clamps.] (2) To finish acquiring the parts to make modifications of the oil pads and their pumping/return system. [We had Krebs make three manifolds for distributing the oil into four capillary tubes for the oil pads. These capillary tubes are designed to replace the orifices we use for compensating the oil pads (see the report on our web site for a discussion of this technique). We decided to make this change because with the tubes it will be possible to clean the things without taking the whole telescope apart.] (3) To get a computer permanently into the telescope for motion-control (perhaps not the final one we will use for telescope operations). [We took delivery of six new computers for the astronomy group and have dedicated one of them to control-system tests. To date, we have been taking it out to the telescope each time we do tests, because that means we are using exactly the same software at the telescope as with our simulator in our lab, but we may begin leaving the computer in the telescope this month.] (4) To build a better simulator for development of the software to look at the focal plane. [We built an integrating box with a light in it with 0.35-mm holes to simulate stars and mounted it in a 6-ft light shield with the Panasonic camera at the other end. This setup gives a reasonable simulation of star images that Williamson is using to develop software for controlling the camera and processing the images of star fields.] (5) To finish assembling the secondary-mirror cell, complete with modifications and test its actuators under computer control. [We have made the modifications required to mount zero-point/limit switches in the cell and begun reassembling the cell. (6) To receive and evaluate Harland Epps's report on the spectrograph camera. [This report is expected in early January.] II. ADMINISTRATION During December we met with representatives of MSFC who would conduct certain tests on the optics and mount of the 2-m telescope. These tests include an optical test of the primary mirror with its axis horizontal, presumably to test the operation of the lateral support system, tests of the vibration of the secondary-mirror support structure for vibration with the telescope being driven at various tracking and slewing rates, and tests of repeatability of the pointing (indication slippage of the friction drive). We requested that they also run tests with accelerometers to define all the important natural frequencies in the mount and determine which ones are active when the telescope is being driven. At this meeting MSFC informed us that, contrary to our agreement with you that the optical test would not cost us anything, we would have to pay about $8000 for equipment for the optical test of the primary mirror. Furthermore, obtaining this equipment will delay this test for about 6-8 weeks, that is from the original middle of October, 1999, to March, 2000. It is not clear to us what the rationale for this optical test might be in light of the report on the mirror from Robert Parks that we presented you in August. Busby has contacted Withbroe for guidance in this question, with no response as of the end of December. We have decided in January to look for simpler ways to make such a test, ways that might also be applied in the field in Arizona for helping adjust both the lateral and axial supports. III. MECHANICAL INTEGRATION Tasks 75&95: Assembly of telescope: We have all three of the drive tractors in the telescope and have adjusted them well enough to begin mechanical tracking tests. We have run such tests under computer control in which we drive both motors in a given tractor simultaneously. All six motors move under electrical control with an analogue demand imposed on the amplifier. However, the aformentioned tests under computer control show that the three tractors still require various amounts of further modification. One of the azimuth drive tractors works reasonably well but requires changing two of its guide rollers(about 2 days of work with tests; the new rollers are in hand). The other azimuth tractor requires more extensive attention, specifically changing guide rollers and adjustment of its hanger (about 1 week of work). The altitude tractor has problems with binding in certain positions, which leads to excessive vibration. We have designed and fabricated some modifications to the tractor and its mount to reduce this binding and will test them on the telescope in December (about 1 week of work concurrent with that on the second azimuth tractor). Task 84: Construct wiring harnesses: We finished rebuilding the cables mentioned in last month's report and tested them in the simulator and started using them in the telescope. This task is now about 90% complete with the remaining work being integrating the controls for small systems into the telescope. This is not yet finished because we still need those cables for tests run in the lab on the buiding head and secondary-mirror cell. Tasks 100-104: Modify oil bearings: This task was covered under I.2 above. IV. CONTROL SYSTEM Work on the control system in December 1999 continued to concentrate on the the basic, device-dependent parts for the motion control. Hedrick spent a week at TSU working on these things as well as on some new computers. He cleaned up the device drivers and made them compatible with the newest, considerably changed, versions of the linux kernel, as well as with the older versions we have been using. This work with him has given us a much better understanding of the motion-control board than we had before. Per Task 168, we have used the computer controller to test motions in zenith distance (essentially complete) and azimuth (still requiring considerably more testing) and to detect slippage of the drives in these motions (see also I.1 above). V. SPECTROGRAPH CAMERA Tasks 187-191: See I.6 above. VI. SMALL SYSTEMS Task 235: Add limit switches to secondary-mirror cell: We got holders for limit/home switches for all six motors that move the secondary mirror designed, manufactured, and integrated into the mirror cell. VII. CALIBRATION SYSTEM Tasks xxx: Acquire fibers. We ordered and received two fiber patch cords from Thor Labs that will let us experiment with hooking up various parts of the system for moving light between the calibration sources, telecope, and spectrograph. We also ordered a longer fiber cable that may serve serve to transfer calibration light to the guiding head with delivery expected in January. Tasks 255-257: Assembly/modification of the guiding head: We continued assembling the guiding head, a low priority, iin December, with addition/testing of the cross slide for the calibration-light feed. We added a limit/home switch to the slide for the pickoff imirror (for acquisition&guiding) and designed a holder for a switch for the calibration slide. Tasks 258&259: Design and build the pickoff mirror: Our machinist finished the blanks in December but has been unable to polish them. In january, we expect to polish at least one of these blanks, probably at TSU, get the machinist to drill the holes for a protype fiber feed in one blank, and get our other machinist to construct a flat target for the guide camera having the same position as the reflected focus of the telescope. VIII. HIGHLIGHTS FOR THE NEXT MONTH During January, 2000, we expect (1) to resolve the questions about which tests of the telescope by MSFC are necessary and which they will do, (2) to finish adjusting the azimuth drive tractors, run slippage tests on them, and decide how to correct any slippage detecterd, (3) to continue working on the oil bearings at a low priority, (4) to mechanically center the top end of the telescope (Task 106), which is marginally necessary to prepare for the vibration tests MSFC plans to make, (4) to finish testing the basic motions in aximuth and Zenith distance (Task 168), (5) to decide what computers to use for telescope control and start procuring them (Task 174), (6) to integrate the Panasonic guide camera into the guiding head, test the camera with a target simulating the focal plane of the telescope, and make the first tests of with it in an actual telescope, (7) to conduct mechanical tests of the secondary-mirror cell (Task 239), (8) finally to receive and evaluate Harland Epps's report on the spectrograph camera, and (9) to investigate ways of simplifying the spectrograph/ camera design by changing the folding mirror between the reimaging mirror.