Date: Fri, 10 Apr 1998 06:03:43 -0600 (MDT)
From: Karen Gloria
Subject: 3.5-m obslog 980409
                          THURSDAY APRIL 9, 1998
                         APACHE POINT OBSERVATORY
                              OBSERVING  LOG
                                                          ACTUAL
ASTRONOMER      OBSERVER(S)        INSTRUMENT   DATE   START FINISH
Stubbs     Diercks, Morgan, Stubbs   SPIcam    4/9-10  20:54 00:28
Turner            Gloria              DIS       4/10   00:28 01:23
Szkody            Hoard               DIS       4/10   01:23 05:15
 INST        SCHEDULED      OBS      WEATH     EQUIP   DAY   NOTUSED
I/RS/DN    START FINISH   D    B    D    B    D    B   USE   D    B
EN01/R     20:54 00:28    -   2.6   -    0    -   1.0   0    -    0
PU01/S     00:28 01:23    -   0.9   -    0    -    0    0    -    0
UW01/R     01:23 05:15    -   3.9   -    0    -    0    0    -    0
(note: times listed include instrument change time)
                               ACTIVITY LOG
(* means a trouble report has been issued or appended to)
The telescope was opened at 18:30 MDT.  I waited until sunset to open
so that the changes in seeing could be monitored during the
engineering time.  The observing schedule was rearranged from the
published version.  EN01 and PU01 traded places.  There was some
trouble with the primary mirror support at the beginning of the night.
I had to intervene, but it pretty much corrected itself, although I
don't understand how.
The observers were Chris Stubbs, Jeff Morgan and Alan Diercks for
EN01, more image quality and guiding tests.
I observed for PU01 and Don Hoard observed for UW01.
I have incomplete focus data - I was busy looking into the PMS
problem.
			     OBSERVER COMMENTS
Stubbs et al. (EN01) - "We encountered a new and interesting
"incident" this evening.  Focus frames showed very peculiar image
quality vs. focus: Although there was a waist in the beam, images were
terrible.
Karen tracked this down to low air pressure in the primary support
system, which she overcame.  The peculiar aspects of this are that
pointing remained essentially constant, and that focus was even close
to the nominal value.  This makes us wonder how we can tell when the
primary is not supplied with adequate air pressure...
Tonight there was essentially no wind. Once the air supply problem was
fixed, we had really superb image quality (0.76 arcsec in R at zenith
for multiple frames).
We checked a number of image quality issues- tested FWHM vs airmass
and passband, and repeated throughput measurements on the polar test
field.
We also checked the degree to which SPIcam and the guider retain a
constant focus relationship vs. rotator angle.
There does seem to be residual aberration (coma?) in the
images. Whether this is due to collimation and/or primary support is
not clear. Also, the images show a consistent anomaly as you run
through focus, with non-monotonic image parameters (FWHM, peak, etc)."
Hoard (UW01) - "An excellent night all around (weather, seeing,
hardware/software behavior), until about an hour before closing when
cirrus developed (had to switch back to the brighter of my 2 CVs).  A
good end to a productive 3 night run."
                                 FOCUS LOG
                               APRIL 9 1997
                  Best   Telescope           Wind            Seeing
Time   Inst      Focus    Az  El   #Temp    Dir MPH  filter  FWHM "
22:15  SPIcam            259  72  4.4/4.6   193  3     R      0.8
00:50  DIS   -150(6172)  319  46  5.0/3.7   207  2     r      1.3
#The first temp is air, the second is truss, both in degrees Celsius
                                 WEATHER
                              APRIL 9 1997
                                   Wind
    Time  Temp F  Dewp. F  MPH.	  Dir.       Dust     Sky       Precip.
     16:01    48    11     11   307  (NW)     617    clear       none
     17:01    44     9     15   292  (WNW)    721    clear       none
     18:01    44     9     12   297  (WNW)    728    clear       none
     19:01    42     9      0   283  (WNW)    840    clear       none
     20:01    39     8      5   358  (N)      769    clear       none
     21:01    40     8      6   276  (W)     1027    clear       none
     22:01    40     7      4   184  (S)     1028    clear       none
     23:01    41     7      6   207  (SSW)   1025    clear       none
     00:01    40     7      2   193  (SSW)   1135    clear       none
     01:01    40     7      1   213  (SSW)   1061    clear       none
     02:01    41     5      0    62  (ENE)   1298    clear       none
     03:01    41     9      1   268  (W)     1269    clear       none
     04:01    40     8      5   280  (W)     1201    cirrus      none
     05:01    39    11      4   281  (W)     1104    cirrus      none
     06:01    41    12      2   264  (W)     1188    cirrus      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: 2.39.
Current guide software version: GIm Ctrlv3.0b11.
-Karen