Date: Mon, 9 Nov 1998 06:21:59 -0700 (MST)
From: Russet McMillan
Subject: 3.5m Night Log 981108
                         SUNDAY NOVEMBER 8, 1998
                         APACHE POINT OBSERVATORY
                              OBSERVING  LOG
                                                          ACTUAL
ASTRONOMER      OBSERVER(S)        INSTRUMENT   DATE   START FINISH
Turner           Gloria              SPIcam     11/8   18:31 19:21
Hereld            Bell               GrIm2     11/8-9  19:21 00:10
York            Mallouris            SPIcam     11/9   00:10 05:04
 INST        SCHEDULED      OBS      WEATH     EQUIP   DAY   NOTUSED
I/RS/DN    START FINISH   D    B    D    B    D    B   USE   D    B
PU01/S     18:31 19:21   0.8   -    0    -    0    -    0    -    0
UC07/R     19:21 00:10   2.4  2.4   0    0    0    0    0    0    0
UC11/R     00:10 05:04    0   1.6   0   3.3   0    0    0    0    0
(note: times listed include instrument change time)
                               ACTIVITY LOG
(* means a trouble report has been issued or appended to)
1st half observing specialist: Karen Gloria
The telescope was opened at 16:00 MST.  I purged the primary mirror
support system with dry nitrogen this afternoon, assuming that the
oscillations reported last night were due to water condensation
somewhere in the support system.  So far tonight we've seen one
possible trailed image, which is an improvement on last night.
The weather looked very unpromising at sunset!  The sky was clouding
up, but it cleared off completely at the start of PU01.  I observed
for PU01 and Eric Bell observed for UC07 from Durham in the UK.  There
were no problems to report, other than the bias level in GrIm2's
quadrants wandering about.  Eric noted that the background level in K'
has been about twice as high this fall as it was last spring.  We
mused on possibilities for this (water vapor?  dust on the primary?).
He's promised to take a close look at his data from this year to see
if he can pin down when the background level went up.
2nd half observing specialist: Russet McMillan
The second half started off well enough, with only a few puffs of
occasional clouds.  The seeing was very poor when we focused, but we
saw no twitches in the PMSS over an hour and a half.  Last night we
had seen some background variation in SPIcam which I thought might be
due to scattered moonlight.  Karen pointed out that the tube which was
rigged up a few weeks ago to feed dry nitrogen to SPIcam might allow a
light leak, so I removed the tube and taped over the hole.
Unfortunately, we didn't have an opportunity to test for light leaks,
because clouds moved in and set up camp.  I closed at 01:45 due to
clouds.  Since the cloud system was too small to see on satellite or
radar images, I kept hoping that it would go away.  However, by the
time the clouds cleared up, the wind gusts and humidity also began to
flirt with the limits.
                             OBSERVER COMMENTS
Eric Bell:
Tonight was good overall, with a tiny amount of light cloud at times, and
seeing that ranged from 0.9 to 1.4 or so arcsec, typically 1.0-1.1 arcsec.
GRIM II worked reasonably well, considering its troubles of late.  The
bias drifted in the two usual stripes, but also the two right hand
quadrants drifted by around 50-100 ADU.  This should be able to be
corrected for, but it introduces uncertainty in a programme with typical
surface brightnesses in the brighter regions of some of our sample of
only 20-30 counts.
Another thing that I noted is the high sky brightness again, typically
around 19-20K per 9.8 sec image.  This exceeds the usual values from
before the summer of around 9-12K per 9.8 sec image.  I'll look into how
it has varied recently in our data, and get in touch again.
Thank Karen for me for her help tonight!
                                 FOCUS LOG
                              NOVEMBER 8 1998
						 Wind
Time   Inst       Focus      Az  El   #Temp    Dir  MPH  filt  FWHM "
18:20  SPIcam  -150(6035)    97  67  3.5/4.2   221  20    r'    1.2
18:25  guider 50618(6029)    96  67  3.7/4.2   214  23    R     1.4
19:30  GrIm2   - 50(6328)   180  59  4.4/4.1   224  18  f/5 K'  1.1
00:20  SPIcam  -125(6051)   167  57  3.5/3.5   236  23    g'    1.5
#First temp is air, second temp is telescope.
                                  WEATHER
                              NOVEMBER 8 1998
                               Wind
     Time   Temp F Dewp F  MPH  Direction    Dust      Sky      Precip.
     16:01    44    27     20   247  (WSW)            clear      none
     17:01    40    30     20   231  (SW)           ptly cldy    none
     18:01    39    30     19   208  (SSW)          mstly cldy   none
     19:01    40    29     19   229  (SW)             clear      none
     20:01    40    31     19   216  (SW)             clear      none
     21:01    40    30     27   222  (SW)         scat. clouds   none
     22:01    39    28     18   251  (WSW)        scat. clouds   none
     23:01    40    27     20   248  (WSW)        scat. clouds   none
     00:01    38    29     18   252  (WSW)        scat. clouds   none
     01:01    38    30     21   241  (WSW)          ptly cldy    none
     02:01    37    32     28   225  (SW)          mstly cldy    none
     03:01    37    27     24   251  (WSW)         mstly cldy    none
     04:01    34    33     19   256  (WSW)          ptly cldy    none
     05:01    34    31     24   227  (SW)          mstly clear   none
     06:01    34    29     31   230  (SW)          mstly 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: 2.42a.
Current guide software version: GIm Ctrlv3.0b15.
- Karen Gloria, Russet McMillan