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0. Filling the dewar
wheel tank over to telescope
insert "probe" into hole in bottom of dewar
hold it with strap so that it is inserted all the way (wear
gloves)
turn on LN2 flow with red handle on tank top (full blast
when vertical)
when dewar is full, liquid spurts out
tube will be frozen; let it thaw in place; wheel tank back
to corner
of platform
1. Login to the data acquisition computer (tambora)
login info is on the white board
left-click; under Telescope Control start up xtcs and xmis
under Data Acquisition start up ccdcom; drag window to
right panel
-> type ccdcom to start
on the left panel, lower-left corner, click on IRAF and ds9
icons
in both the IRAF and ccdcom windows, cd to
/data/tambora/obs13m/
make a main directory there (e.g., kay) for data
in kay, make subdirectories for each night (e.g., n1, n2,
etc.)
Each night:
-> cd into appropriate directory in both IRAF
and ccdcom windows
-> set file prefix for the night's data with
"fp" (e.g., fp n1)
in ccdcom
2. ccdcom basics
UNIX: you can cd and ls in ccdcom; all other unix commands
must be
prefaced with "!" (shell
escape)
two steps needed for an exposure: set-up command and
"go"
set-up: for biases: "bias"
for flats: "flat (exp
time) (image title)"
for objects: "object (exp
time) (image title)"
for focus run: "focus (exp
time) (image title)"
expose: "go <#>" where # is number of
exposures (default = 1)
altering an exposure:
Ctrl-C -> pause
go -> resume exposure
rc -> read-out CCD and save image
cl -> abort exposure, don't save
image, clear CCD
et -> change exposure time
alter image number: fn <#>
-> can set file number back to zap undesired image(s)
-> ccdcom will prompt you before overwriting an
existing image
-> can delete image(s) (be careful!) in iraf
with "imdel
command if you don't want ccdocm to
ask you about overwriting
3. Bias images
possible light leak; may need to apply black tape to dewar
where it
attaches to filter wheel; ask Bob Barr about it
to be safe, make sure it's dark in the dome
in ccdcom, type "bias" then "go 15" (15
is good; do at least 10)
4. Dome flats
open mirror cover and instrument hatch
power up telescope
-> turn on tv monitor on top of console
-> turn console power to on
-> press start (kachunk)
dome should be at "home" position (azimuth = 51
deg)
-> you know dome is home if shutter can be
opened
slew telescope to HA = +01 19 11
dec = -12 10 30
turn on flat field lamp (on telescope pier); turn off dome
lights
some exposure guides with templeton (3/06): and can be adjusted for other detectors
HA: dimmer at full, exposure = 3 sec
R: dimmer pointed at screw at 6:00, exposure
= 2 sec
I: dimmer at mark on plate at ~ 5:00, exp =
2-3 sec
take a flat; check counts in image (want ~ 25K - 30K
counts/pix)
-> adjust exposure if necessary (not dimmer,
unless you saturated)
take at 5-10 flats in each filter (can say "go 9"
after exposure is set)
when done, turn off FF lamp, return telescope to zenith,
close
instrument hatch and mirror cover
5. Opening up for the night: go through Startup Checklist
might want to reset dome encoder before moving dome; with
dome at
home position, go to xtcs window, setup, Set Dome
Az Encoder
Dome Home Position is 51 deg.
6. Twilight sky flats -- do you really want to do them? If so,
a good guide can be found at http://www.noao.edu/0.9m/Tel_Op.html
scroll down to Appendix J (sky flats); read it before you
start
if doing narrow-band filters (H-alpha) start with these,
then U, B, etc.
remember: telescope tracking ON; jog the telescope position
WEST
between every exposure
~20K - ~40K cts/pix ok
7. Check pointing (in twilight)
get Yale bright star catalog from bookshelf
look for star with RA ~ current (or near-future) LST, dec ~
30 deg,
V ~ 6 (don't want one that's too bright)
get accurate coords from simbad
move telescope there
take 1 sec exposure
figure out offset needed to center star; in ds9, image is
inverted
(N down, E right); image scale is 0.5 arcsec/pix
(templeton)
when star is centered, enter coords in xtcs window
in setup, Set RA/Dec Encoders
optional: move guide probe to "center" (keep
voltage low) mark spot
on guider TV where (centered) star is; move probe
to "origin"
8. Focus telescope -- at bright star field (if there are other stars there)
use "imexam" in iraf to see how brights other
stars in field are;
figure out good exposure time for them
do focus run
-> how good is current focus?
-> move focus IN a ways, then OUT to starting
focus value
-> set-up focus run in ccdcom; type
"go"
-> when prompt returns: run focus OUT 5 units
jog telescope in dec ~30" SOUTH
type "go"
repeat total of 7-9 times
-> after last "go" type "rc"
to read out
-> display image in iraf
determine focus
-> first focus position is at top of sequence of
star images
-> use imexam to check profile, measure FWHM
-> if not sure, do for all filters (I think
UBVRI & HA are parfocal)
-> move telescope focus IN past correct focus,
the OUT back to it
9. Observing objects (with guiding)
move telescope to object
-> if encoders are set, 2000 coords should
center target (maybe test
this hypothesis with a standard star)
-> can always move guide proble to origin, look
for something you
recognize on the guider tv, and bump
the telescope to center
target if necessary
set up guider
-> in xmis window, go to Guider Preset, and set
units to arcsec
-> move probe to x=1200, y=1200; one needs to be
proble will shadow CCD image;
look for a star
-> can turn up guider voltage (to ~ 4V) &
increase gain (shift-Z)
-> if no star there, try changing y position in
+/- 300 unit steps
-> better yet, figure out how to use
Thorstensen's guide star tool!
guide
-> move box to star with arrows; "5"
on keypad toggles between
fast/slow
-> make sure no star in background ellipse
-> start guiding with "s"
-> quit guiding with "q"
expose
-> check the filter!
-> check guide probe position!
before moving telescope
-> quit guiding
-> turn guider voltage all the way down
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2006-26-04