From: Russet McMillan Subject: 3.5m Night Log 20000323 Date: Fri, 24 Mar 2000 06:18:43 -0700 (MST) THURSDAY MARCH 23, 2000 APACHE POINT OBSERVATORY OBSERVING LOG ACTUAL ASTRONOMER OBSERVER(S) INSTRUMENT DATE START FINISH Gillespie Morgan, McMillan, SPIcam, 3/23-24 01:30 05:08 Loomis guider INST SCHEDULED WEATH EQUIP OBS DAY NOTUSED I/RS/DN START FINISH D B D B D B USE D B EN01/S 19:11 05:08 0 0 0 0 2.7 7.2 0 0 0 (note: times listed include instrument change time) ACTIVITY LOG Observing Specialist: McMillan The night started out partly cloudy and gradually improved. Seeing measurements were horrible with DIMM, especially in the evening -- but when SPIcam and the guider were in use during second half, some images were smaller than an arcsecond. Opening was delayed in the evening because the telescope's top end was still off, waiting for some adhesives to dry. New Heidenhain encoders were attached to the secondary as motion monitors. Tests of secondary motion with the top end off the telescope confirmed the same things we've seen in the guider data; small moves show significant errors, especially when reversing direction from previous moves. All three actuators show some trouble with small moves, but the C actuator is the worst by far. At 22:30, the top end was replaced on the telescope and we did some further tests of the secondary behavior using the new encoders, including a transverse encoder to measure sag. Some disturbing trends were noted, especially in the behavior of actuator C at different altitudes. While we made tests at various altitudes, we also watched the primary LVDTs. These were showing considerably more motion than normal. Although they usually recovered by the end of a slew, there were examples where it took many tens of seconds to return to the correct position. Problems were more noticeable at low altitudes, where axis A was especially troubled. During the later pointing model, it was apparent that A, B, and C tended to have trouble moving from low altitude to higher altitudes, while the transverse LVDT showed difficulties when starting from a high altitude and moving down. The dome was opened at 01:30, but no actual images were taken until about 03:00. Once the secondary motion tests were done, we did a quick tip/tilt sequence with SPIcam to establish collimation, and followed this by a pointing model using the correct values for the guider instrument block. All instruments should now have correct instrument blocks, and we expect to see a large improvement in pointing with GRIM and tracking with DIS. At 04:30, we tried switching to the Shack-Hartmann for some tests to establish the rotation of the instrument relative to the telescope, but there was an intermittent communication problem which prevented moving from "mirror" to "reference" mode and back. Jeff Morgan found a loose connector which probably accounted for the problem, but the delay was enough to prevent us from getting and S-H images before twilight. We worked into twilight taking pinhole images with SPIcam to establish sources of scattered light. OBSERVER COMMENTS FOCUS LOG MARCH 23 2000 Wind Time Inst Focus Az El #Temp Dir MPH filt FWHM " 03:25 SPIcam -20(50) 156 74 0.6/0.9 318 9 none 0.94 #First temp is air, second temp is telescope. WEATHER MARCH 23 2000 Wind Time Temp F Dewp F MPH Direction Dust Sky Precip. 16:01 36 24 9 350 (N) 753 ptly cldy none 17:01 36 26 1 276 (W) 806 ptly cldy none 18:01 32 24 5 327 (NNW) 859 ptly cldy none 19:01 32 21 11 20 (NNE) 808 ptly cldy none 20:01 36 7 14 12 (NNE) 573 ptly cldy none 21:01 37 2 6 33 (NNE) 729 ptly cldy none 22:01 35 12 4 355 (N) 729 mstly clr none 23:01 34 19 8 359 (N) 834 mstly clr none 00:01 38 17 10 339 (NNW) 897 mstly clr none 01:01 37 18 14 318 (NW) 772 mstly clr none 02:01 37 18 11 325 (NW) 778 clear none 03:01 34 22 9 330 (NNW) 921 clear none 04:01 35 22 8 273 (W) 999 clear none 05:01 34 21 12 302 (WNW) 831 clear none 06:01 35 16 11 303 (WNW) 859 clear none note: the wind was coming from the azimuth listed. The convention used is north=0 degrees, east=90 degrees. The dust count is particles > 1 micron per 0.1 cu. ft. TELESCOPE STATUS Primary, secondary, and tertiary mirrors in place and collimated. Primary support system operational. Mirror ventilation system in place. Telescope drives operational. Current Remark version: 2.55b5. Current guide software version: GIm Ctrlv3.0b27. Current TCC version is 2.2.2. - Russet McMillan