Date: Sat, 14 Nov 1998 06:10:15 -0700 From: long@apo.nmsu.edu (Dan Long) Subject: 2.5m obslog 981113 FRIDAY NOVEMBER 13, 1998 APACHE POINT OBSERVATORY SDSS 2.5m OBSERVING LOG Tonight, for the first time, we used the TCC to slew and track the 2.5m telescope! While not an unqualified success, it was a significant step forward. See the rather lengthy log for details. Thanks to Charlie Briegel for staying up nearly all night working on the MCP software. There was a slight delay in opening due to high humidity. We opened at about 19:00. When I went down to open I found quite a bit of liquid which had sprayed out of the top of the air trap on the ground loop. It had stopped when I checked it and otherwise it seemed to be working. I also found the valves connecting the Neslab to the ground loop shut off. As they need to be open for the Neslab to dump heat, I opened them. The telescope was parked on the equator at the meridian, and a scan was started. The images were strongly comatic at the primary settings from the last night of the dark run a couple weeks ago. setmir 0 -1.3 5.7 305 80 galil 4700 -3550 300 -10350 1050 1050 It was decided to home the primary and return to the values Pat had found before the start of the October dark run. The output of that command follows. Note that very little position error was found. :XQ#STATUS : 0000004700, -0000003550, 0000000300, -0000010350, 0000001050, 0000001050 current position 0000004700, -0000003550, 0000000300, -0000010350, 0000001050, 0000001050 target position 0000000000, 0000000000, 0000000000, 0000000000, 0000000000, 0000000000 position error 00065537, 00065537, 00065537, 00065537, 00065537, 00000001 status word 1, 1, 1, 1 M1 supports (0 retracted, 1 normal, 2 extended) 00002, 00002 M1 proximity sensors OK XQ#HOME : 0006.2, 0006.2, 0006.2, 0004.7, 0010.6, 0010.6 max sec to find reverse limit switch at high speed 0030.1, 0030.1, 0030.1, 0030.1, 0030.1, 0030.1 max sec to find home switch transition 0000.4, 0000.4, 0000.4, 0000.4, 0001.5, 0001.5 sec to move out of limit switch again 046, 001.7 microsteps, sec to find full step 000000000, 000000000, 000000000, 000000000, -000000050, -000000049 position error -0000120000, -0000120000, -0000120000, -0000090000, -0000050000, -0000050000 current position 06 00000050, 00000256, 01.40 # axes, microsteps/full step, param word, software version -0000120000, -0000120000, -0000120000, -0000090000, -0000050000, -0000050000 reverse limits 0000120000, 0000120000, 0000120000, 0000090000, 0000050000, 0000050000 forward limits 0000050000, 0000050000, 0000050000, 0000050000, 0000012000, 0000012000 speed 0000500000, 0000500000, 0000500000, 0000500000, 0000120000, 0000120000 accel 0000000000, 0000000000, 0000000000, 0000000000, 0000000000, 0000000000 encoder resolution (ticks/step) 01.10 version of M1-specific additions OK The primary was then put at the following position, and several cycles of setmir and down were issued. setmir 0 -26.3 10.7 1675 350 galil 6350 -4650 -250 -5700 44400 44400 These values virtually eliminated coma, so apparently the truss pinning was not the source of the changes seen on the last night of the October dark run. Most of the rest of the night was spent getting the TCC - MCP interface so that track commands from the TCC would slew the telescope. The bottom line is we got the telescope to track! Things are still a bit fragile, and there are some rate errors, but not a bad first attempt. In particular, we took staring frames at the equator and meridian, as well as about 15 degrees from zenith, and in the east. There appeared to be some mistracking, most notably in the rotator. It looked as though there was a fixed offset from the proper rate. That is, the faster the rotator was tracking, the better the images looked. We even got arbitrary driftscan direction to work to some degree. We never got good images in all dewars, but could get it so a particular one looked nice. There was a puzzling object rotation required to make things work, of 213 degrees. Since the instrument block ( a fake construct based on the DIS instrument block ) had a zero rot_inst_ang, and the actual camera wanted to be at 90 ( mount ), one would have thought the object rotation would have been +/-90 degrees, but I am probably just missing something. There were several curious types of failure when trying to track. On many occasions an axis would fail to respond because an amplifier tripped part way through a slew. We also found you couldn't issue another track command while the telescope was already tracking, even if it was in mount coordinates. The same went for trying to send a rotate command while tracking. The response would be 0 0 F Modu="mov_TrapSlew"; Text="Telescope is moving too fast. Stop the telescope, then try your slew again." Also, after only a few minutes of tracking, and sometimes much more quickly, status would die with the following message. 0 0 F Modu="msg_FormatStatusAxePos"; Text="format failed; position is probably invalid" A couple of examples of garbage getting through without crashing status are listed below. This isn't proper information, but I don't think status should bomb just because it recieved garbage input. It should complain, but soldier on, and if possible display the offending entry. 0 0 I SpiderInstAng= 23.465178, -0.009952, 4417755036.99000 0 0 I SpiderGImAng= -155.564922, -0.009952, 4417755037.00000 0 0 I TCCStatus="SSS--S","NNY"; TCCPos= 26.88, 71.79, 185.15,NaN,NaN; AxePos= 20.88, 71.79, 185.14,NaN,NaN 0 0 I SpiderInstAng= 23.440292, -0.009957, 4417755039.49000 0 0 I SpiderGImAng= -155.589802, -0.009952, 4417755039.50000 0 0 I TCCStatus="SSS--S","NNY"; TCCPos= 26.85, 71.79, 185.13,NaN,NaN; AxePos=-951.58, 71.79, 185.13,NaN,NaN 0 0 I SpiderInstAng= 23.415394, -0.009961, 4417755041.99000 0 0 I SpiderGImAng= -155.614700, -0.009957, 4417755042.00000 0 0 I TCCStatus="SSS--S","NNY"; TCCPos= 26.83, 71.80, 185.11,NaN,NaN; AxePos= 22.48, 71.80, 185.11,NaN,NaN 0 0 I TCCStatus="SSH--S","NNN"; TCCPos= 80.00, 70.00,NaN,NaN,NaN; AxePos=6671.78, 70.00, 229.55,NaN,NaN 0 0 I TCCStatus="SSH--S","NNN"; TCCPos= 80.00, 70.00,NaN,NaN,NaN; AxePos= 47.32, 70.00, 229.55,NaN,NaN 0 0 I TCCStatus="SSH--S","NNN"; TCCPos= 80.00, 70.00,NaN,NaN,NaN; AxePos=6672.29, 70.00, 229.55,NaN,NaN 0 0 F Modu="msg_FormatStatusAxePos"; Text="format failed; position is probably invalid" One last thing about telrun, is an apparent change in the behavior of "up-arrow". In the interpreter, one can only up-arrow to the previous command, and no further back. At the $ prompt one can still go several commands back. Dan