Date: Mon, 3 May 1999 07:34:47 -0600 From: long@apo.nmsu.edu (Dan Long) Subject: 2.5m obslog 990502 ( MJD 51301 ) SUNDAY MAY 2, 1999 APACHE POINT OBSERVATORY SDSS 2.5m OBSERVING LOG The telescope was opened at about 20:00. After trouble with the altitude fiducial barcode reader, and with the GPS clock, we finally got on the sky at about 01:30. We got a total of four data points on Vega, and three on Procyon. Details are below. When I went to set the altitude fiducial tonight, I would never get a crossing, no matter which one I crossed, and no matter which direction. I noticed that the barcode reader did not have a ready light, which was always on in the past. Wiggling cables did not help. When the power supply was checked, the two 1 amp fuses inside were blown. After a fruitless search for the odd sized fuse, Matt Newcomb rigged up something that would use the normal size fuse. When we went to apply power ( after having disconnected all cables from the box ), and the fuses blew instantly. We decided to try using the Az barcode power supply to do both Az and Alt one at a time. The azimuth fiducial was set, then the cables were swapped so that the altitude reader was connected to the Az power supply. When powered up the ready light on the reader never came on, and never triggered a read when fiducials were crossed. A check of the power supply showed it getting warmer than it did with the Azimuth reader connected to it, so we disconnected altitude and reconnected Az and the azimuth reader still functioned properly. At this point we turned to Charlie Briegel, and he helped us modify the MCP so that any time an altitude fiducial was crossed it was called #2 ( the 15 degree valid fiducial ). Since the Heidenhain was still registering each fiducial, it was simply a matter of convincing the MCP that when the 15 deg fiducial was crossed, it was OK for us to hit "F" and set it. This was completed by about 00:30, and we thought we were finally ready to get started. I slewed to Vega, then noticed the TCC complaining about the inability to resynch its clock. This had happened earlier in the night, but Craig had traced it to some commo problem related to the GPS receiver getting into a strange state when odd control characters come down the line. At some point after this it stopped finding satellites, and it took a very long time to get going again. In the mean time it managed to send the TCC a time that was off by something like 30 seconds. With the other GPS out getting an upgrade, it is a bit worrysome that the remaining one seems to be acting up. After something like an hour it corrected itself and we ran the rest of the night, without further time complaints. We ( Pat Waddell, Bob Nichol, Matt Newcomb, and I ) managed to get starlight from Vega down 4 fibers. We also repeated three of the fibers on Procyon. Below is a list Bob Nichol sent me of the fiber positions we used tonight. FFAST FIELD K ----------------------------------------------------------------------- name ID RA DEC x(mm) y(mm) A 11014983 GUIDE 229.7228625 -0.107868 -60.2640152025 -23.4529150921 B 11017890 GUIDE 230.2655475 0.329789 57.7592533267 71.7244995065 C 11017817 GUIDE 230.2435755 0.668087 53.0140559153 145.398150495 D 11014602 GUIDE 229.653363 -0.821959 -75.467707212 -178.942727397 E 11018529 GUIDE 230.392371 1.140229 85.4633526642 248.361274855 F 11013673 GUIDE 229.4871255 -1.354281 -111.81458517 -295.275668412 G 11023706 GUIDE 231.323688 0.485062 288.567956973 105.743546872 H 11012657 GUIDE 229.2921075 1.150633 -154.261239557 250.753120517 I 11009720 GUIDE 228.764211 0.509003 -269.311071784 110.925809525 A -.2771375 -0.107868 B 0.2655475 0.329789 C 0.2435755 0.668087 D -.346637 -0.821959 E 0.392371 1.140229 F -.5128745 -1.354281 G 1.323688 0.485062 H -0.7078925 +1.150633 I -1.235789 +0.50900 First we used Vega 279.2221, 38.7822 fk5=1999.5 ( all coords 1999.5 ) then Procyon 297.6896, 8.8669 A offset -.2771, -.1079 deg RA/Dec Starting coords Obj offset required to center Vega: 279.4992, 38.8901 .0847, .0034 deg RA/Dec Proc: 297.9667, 8.9748 .0049, .0030 deg RA/Dec B offset .2655, .3298 deg RA/Dec Starting coords Obj offset required to center Vega: 278.9566, 38.4584 -.0693,-.0026 deg RA/Dec Proc: 297.4241, 8.5371 -.0020, .0030 deg RA/Dec C offset .2436, .6681 deg RA/Dec Starting coords Obj offset required to center Vega: 278.9785, 38.1141 -.0630, .0035 deg RA/Dec Proc: 297.4460, 8.1988 -.0010, .0030 deg RA/Dec E offset .3924, 1.1402 deg RA/Dec Starting coords Obj offset required to center Vega: 278.8297, 37.6420 -.1045, .0043 deg RA/Dec We were running into bright twilight by the point Procyon was on C. So we only got three on Procyon. The telescope was closed up shortly before 06:00. Dan