From: Russet McMillan Subject: 3.5m Night Log 20060614 Date: Thu, 15 Jun 2006 06:13:22 -0600 (MDT) Apache Point Observatory 3.5m Telescope Night Log Wednesday, June 14, 2006 ACTUAL ASTRONOMER OBSERVER(S) INSTRUMENT START FINISH -------------------------------------------------------------------- M.Klaene R.McMillan S-H, DIS 01:30 05:20 INST SCHED(TWILIGHT) WEATH EQUIP OBS DAY NOT USED I/ROW/DN START FINISH D B D B D B USE D B ---------------------------------------------------------------------- EN01/O 21:16 04:51 2.0 2.2 0 0 0 3.4 0 0 0 note: scheduled times listed include instrument change time ------------- ACTIVITY LOG -------------- Observing Specialist: R.McMillan Clouds over the basin at sunset were producing virga that seemed to be getting very close to our altitude. I decided it would be best to stay closed for a bit, since the first tasks I had to work on were easier with a closed dome anyway. I confirmed some of Jack's work yesterday with the new blue grating for DIS. Although it was originally installed as instructed, the orientation that Jack put it in gave the expected signal levels. A direct comparison of the old blue low (300 l/mm) grating versus the new blue medium (400 l/mm) grating with the same slit and exposure time showed slightly higher peak counts with the new grating even though the dispersion was higher. This is exactly what we ought to be seeing, so I concluded that the current orientation must be correct. I realized the anomalous zero-step measurements that Jack got last night were due to the ICC having the wrong dispersion for the new grating; it couldn't place the requested wavelength in the center if it didn't know the dispersion. Craig updated the configuration data, and the new zerostep for the new grating was 300, exactly what it should be. This (and the as-predicted resolution) confirms that we are in the correct order of the spectrum. Craig and Russell will be working in the next few days to get the software to accept the new proposed grating names (see http://www.astro.princeton.edu/APO/apo35-general/msg.964.html) In the middle of the work on the gratings, I noticed an error message that the TCC's VAX clock couldn't be calibrated. When I checked, the 2.5m was having the same problem. I called Fritz, and he talked me through moving some cables from one GPS clock to the other; everything seemed fine after that. Fortunately, neither telescope had been on the sky before the problem was noticed. After 01:00, I felt the precipitation threat was gone, but there were some troublesome clouds around. I decided to open anyway and do what I could through the clouds. I rechecked the altitude tracking, since I was especially interested in high southern transits where we've seen some trouble in the past. Conditions were not ideal, with a stiff southeast wind, poor seeing, and varying clouds doing bizarre things to the image. Nevertheless I think I could tell that tracking is as good or better with the new drive. Almost all the image motion I saw was wind forcing or PMSS motion. I did make a small adjustment to the altitude PE.RATE, because I imagined it reduced backtalk between the altitude and PMSS. That may have been illusory, but the new value is reasonable and well within the range we've used in the past. Next I measured collimation, which in practice meant sitting around waiting for clouds to clear and seeing to settle. I got three usable images out of a set of 15, and confirmed that the collimation is fine. While some more clouds passed through, I hunted down log data for some slews that appeared suspicious on the dataq and sent the timestamps to Mark to investigate in more detail. During a mostly-clear patch, I observed some stars with DIS to compare the new blue medium grating with the old blue low grating. Conditions were not good enough for proper throughput measurements, but I did confirm that the new grating gave similar peak counts to the old grating (meaning throughput about 1.3 times as good as the old one, allowing for the higher dispersion). I also found that the stellar spectrum was slightly tilted on the chip in the opposite direction from the spectral lines, meaning the dispersion is not orthogonal to the slit. This merits further work to improve the rotation of the grating. I finished up with a pointing model which went into twilight, then got cut off when the guider crashed halfway through. The sky was mostly clear at that point, so I decided instead of power-cycling the guider, I would do a couple more quick spectra with DIS in hopes that they could be used for throughput measurements. Halfway through THIS, the DIS slitviewer crashed. I took it as a sign that it was time to quit. ------- FAILURE LOG ------- PROG INST FAILURE MODE TIME (SEDFNVOG) TI/SHU START FINISH DESCRIPTION ----------------------------------------------------------------------- ---------------- FOCUS LOG --------------- Air/Truss Wind Time Instrument Focus Az El Temp-C Dir MPH filt FWHM --------------------------------------------------------------------- ------------- WEATHER LOG ---------------- Wind Precip.or Time Temp F Dewp F MPH Direction Dust Sky Conditions ------------------------------------------------------------------ 16:01 78 34 18 242 (WSW) 1490 ptly cldy none 17:01 79 35 15 237 (WSW) 1605 ptly cldy none 18:01 75 31 18 198 (SSW) 1351 ptly cldy none 19:01 75 31 18 227 (SW) 1284 ptly cldy none 20:01 70 27 17 210 (SSW) 1421 ptly cldy none 21:01 69 26 13 194 (SSW) 1513 ptly cldy none 22:01 68 25 13 180 (S) 1633 ptly cldy none 23:01 69 27 14 187 (S) 1385 ptly cldy none 00:01 69 27 14 164 (SSE) 1446 ptly cldy none 01:01 64 35 14 141 (SE) 1538 ptly cldy none 02:01 65 29 23 180 (S) 1452 ptly cldy none 03:01 65 27 15 177 (S) 1813 ptly cldy none 04:01 62 30 23 174 (S) 1510 ptly cldy none 05:01 63 28 25 192 (SSW) 1605 mstly clr none 06:01 62 28 22 185 (S) 1610 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 > 1u per 0.1 cubic feet. TELESCOPE STATUS Telescope drives operational. Current TCC version: 2.8.4 Current TUI version: TUI 1.2