TSU 2-m AUTOMATIC SPECTROSCOPIC TELESCOPE PROJECT


                          Monthly Report for January, 2000


     This monthly report for the TSU 2-m AST project covers the calendar month of 
January, 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--VI) 
covers the status of various tasks in the schedule; and a third part (VII) gives  
highlights for February.  During January, 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.  Undergraduate student Kenneth 
McDavis rejoined us to do a project related to the control system.


                          I. HIGHLIGHTS FOR THE PAST MONTH

     During January, 2000, we said we expected to do the following things [with steps 
taken then in brackets]: (1) To resolve the questions about which tests of the 
telescope by MSFC are necessary and which they will do. [After resolving uncertainties 
caused by different understandings by various NASA officials of the technical readiness 
of MSFC to perform certain tests, we started these tests in January.  Some of the tests 
were scheduled for late January (mechanical tests of repeatibility, vibration, and 
resonances) and the rest for some later date, probably in February (tests of lateral 
mirror supports).  A group from Marshall came up on 26&27 January to run various 
mechanical tests.  They used a laser mounted to the instrument head and focused on a 
TV camera in the secondary-mirror cell to assess vibration of the telescope when driven 
at various rates and in settling down from a slew; they used a theodolite with targets 
on the telescope mount to determine how well the drives repeat (whether they slip 
appreciably); and they put accelerometers on several parts of the mount to measure 
resonances excited by the drives.  For the most part, these tests were successful and 
found no serious problems with the telescope.  The tests with accelerometers, which we 
requested to determine the natural frequencies of the mount, gave roughly what we had 
expected for the quadrapod supporting the secondary mirror.  It found the fundamental 
torsional mode at appx. 16 cps vs 17.2 in our FEA calculations.  A well-defined 
resonance seen at 70 cps may correspond to calculated rocking modes at 52 or 76 cps. 
We expect to get reports from Marshall on these tests, particularly the measurements 
of resonances detected, in February.  The test of the lateral supports is delayed for 
MSFC to order some small pieces of equipment needed to do the test.]  (2) To finish 
adjusting the azimuth drive tractors, run slippage tests on them, and decide how to 
correct any slippage detecterd.  [We have adjusted the three tractors well enough that 
they let us run the telescope through its full range of motions in both axes at all 
the rates we expect to use.  We still have tests planned for rebuilding the tensioning 
mechanisms to eliminate the clamps, which we expect to do before shipping the telescope 
to Arizona.  We have run a series of slippage tests on the tilt axis using a dial 
indicator to tell how well the axis returns to its original position after various 
displacements.  This method is more precise (0.001 inch = 4-5 arcsec) than the roughly 
(+/- 1 arcmin) precision of MSFC's test with the theodolite.  However it suffers, at 
least for the tilt axis, from the fact that we indicate off the drive tractor, which 
itself might deflect somewhat.]  (3) To continue working on the oil bearings at a low 
priority.  [We have ordered certain parts required to rebuild the compensation system 
to make it more robust and expect to modify the bearings when the telescope is 
partially torn down for shipping, with tests of the modifications to be done with the 
bearings supporting the fork.]  (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. [We used a plumb bob hanging vertically from the middle of the 
secondary mirror cell to determine how much the top end is off center (roughly 1/8 in
along tilt axis and 1/2 inch perpendicular to it).  We tensioned the cables stiffening 
the top end for MSFC's mechanical tests and deferred relocating the feet because we 
did not have time to lift and relocate the the top end before those mechanical tests.] 
(5) To finish testing the basic motions in aximuth and Zenith distance (Task 168).  
[These motions seem to be working fairly well as of late January.  We still have to run 
long term tests of the motions to see that they will work for many hours.]
(6) To decide what computers to use for telescope control and start procuring them 
(Task 174).  [We have deferred this task to February after deciding to use one of 
a set of five new computers procured for us by Andre Hedrick for tests and to leave 
it in the telescope during the time of these tests.]  (7) 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.  [Williamson has continued testing this camera, we have integrated it into 
the guiding head, and he has begun testing it there.  We have located a telescope to put 
it in for taking pictures of some actual starfields and have ordered and received an 
adapter to attach it to that telescope.  Williamson has taken the camera, a small camera 
lens, and the frame grabber home to use with his computer to take some pictures of star 
fields for this purpose.] (8) To conduct mechanical tests of the secondary-mirror cell 
(Task 239).  [This task is deferred because the secondary mirror cell was needed to 
check the centering of the top end of the telescope and to mount the TV camera for 
MSFC's mechanical tests.] (9) Finally to receive and evaluate Harland Epps's report on 
the spectrograph camera.  [We received Epps' report on January 5.  Both Eaton and Fekel 
have read the report, and we have mailed a copy to Peter Maymon for him to review.]
(10) To investigate ways of simplifying  the  spectrograph/camera design by changing 
the folding mirror between the reimaging mirror. [We calculated several models with a 
concave mirror used to fold the beam between the two reimaging mirrors.  To our 
knowledge, nobody has investigated this approach before. We were able to eliminate 
the change in focus across an order of the echelle spectrum with a imirror having the 
same curvature as the two reimaging mirrors, but the approach gave more astigmatism, 
at least in the first application.] 



                                 II. ADMINISTRATION

     During February Eaton will make a fact-finding trip to Arizona (Task 34).  He will 
visit Fairborn Observatory to determine what, if anything, needs to be done to prepare 
the site for the 2-m telescope and to talk with Boyd about isome parts of the system.



                           III. MECHANICAL INTEGRATION

Tasks 75&95: Assembly of telescope:  Assembly of the telescope is essentially finished.
There remain, however, a number of acceptance tests required for our certification of 
the telescope as ready for shipiping to Fairborn Observatory, per the criteria we sent 
in November.


                                  IV. CONTROL SYSTEM

     Work on the control system in January 2000 continued to concentrate on the the 
basic, device-dependent parts for the motion control.  Williamson has taken over most of 
this task and is progressing steadily.  We expect to integrate the two parts of the control 
system, namely the calculation of instantaneous positions of targets and the code that 
runs the dirve motors in the lab for realistic simulations of the basic parts of the control 
system in February.

     We have a student, Kenneth McDavis, that is doilg a study of the availability of guide 
stars in random fields around the sky.  (He was supposed to do this last semester but 
drifted away.)  He is printing out about 120 fields from the STScI Palomar atlas and 
derermining the numbers and brightnesses of stars in them.  We will use his results to 
sharpen up our guiding strategy.



                               V. SPECTROGRAPH CAMERA

Tasks 187-191: We have finished the preliminary design of the spectrograph, reviewed it 
internally, and sent it off to Peter Maymon for his review.



                               VI. CALIBRATION SYSTEM

Tasks 255-257: Assembly/modification of the guiding head:  We finished assembling the 
guiding head by adding all the moving parts with appropriate zero-point switches and 
setting up the guide/acquisition camera to look at a special target in place of the 
pickoff mirror.  Williamson has used this setup to test focusing of the guide camera 
and to determine the scale of the camera.  Eaton will discuss the guide camera and its 
control with Boyd in February.  We expect to take the guiding head apart and get the 
aluminum parts anodized in late February.

Tasks 258&259:  Design and build the pickoff mirror:  Our machinist polishing one of the 
blank pickoff mirrors enough to see how to finish doing it.  On 24 January, he and Eaton 
bored holes in this prototype for a fiber feed that we will use in tests of the 
acquisition/guiding system.  We have obtained all the parts necessary to make up a 
prototype of the connector that will lead the fiber through the mirror, and we have 
constructed a jig for putting the thing together.

Tasks 263:  Acquire fibers.  We received a 12-meter fiber patch cord from Thor Labs
that will let us experiment with hooking up the feed between the guiding head in the 
telescope and the instruments (spectrograph & calibration sources) in the control building.
We have since ordered from Thor Labs two 12-m fibers terminated at one end to use to 
experiment with building the adapters that will go in the guiding head (through the holes
in the pickoff mirror.  These cables may, depending on their measured quality, serve 
in the actual scientific instrument.

Tasks 267-269:  Calibration bench:  We (Fekel and Eaton) have designed the calibration 
system for the spectrograph and ordered all of the parts to build it.  It will consist of 
a continuum source projected onto the end of an optical fiber at f/8 with a ThAr line 
source projected onto the fiber with a flip mirror.  These components will be mounted on 
an 18x24-inch optical bench with standard lab mounts, mostly from Ealing.  About half of
the parts are delivered, and most should be in hand by Early March.  We expect to assemble 
the calibration bench in March and April and then use it for tests with the guiding head.


                            VII. HIGHLIGHTS FOR THE NEXT MONTH

During February, 2000, we expect (1) to run MSFC's test of the lateral mirror support system 
(Task 119),  (2) to run further slippage tests on the altitude and azimuth drive tractors, 
(3) to finish adjusting and pinning the top end (Task 106),  (4) to finish testing the basic 
motions in aximuth and Zenith distance (Task 168, extended),  (5) to decide what computers 
to use for telescope control and and control of the CCD in the spectrograph and start 
procuring them (Tasks 147 and 174),  (6) to continue integrating and testing the Panasonic 
guide camera in the acquisition/guiding head, and to make enough observations of stars 
with the camera to assess a limiting magnitude for acquisition and guiding (part of Task 
175),  (7) to conduct mechanical tests of the secondary-mirror cell (Task 239), and (8) to 
decide how to proceed with procurement of the spectrograph camera.