Created 04/09/09 by Gabor F
HTML and editing 06/22/09 by Ted G
Using The Tres Guider
1: STARTING UP THE GUIDER
Login to tres-guider.sao.arizona.edu as tres using ssh.
(or through vnc use the tres-guider.sao.arizona.edu:2 connection)
Cd to the /home/tres/guidebin directory
Run the command ./tresguide start
similarly, to stop or restart an already running code:
at this point three windows should appear:
Tresbox : the user GUI Tresbox
Guider Control : more an engineering control Guidercontrol
Guidegui : a special DS9 to display images Guidegui
A message in the window "detector server not connected"
indicates that the guider was likely not powered up or
the fiber optic link between the guider PC and the camera
electronics box is not connected properly.
WINDOW DESCRIPTIONS: 1 - TRESBOX
Guide row (top):
Start/Stop buttons start/stop the guiding, e.g. when the software
is determining the centroid of guide images and sending corrections
to the tip/tilt mirror. The leftmost button is the status indicator.
View row (middle):
Select which of the three DS9 panels to update real time. The readout
of the two upper guide-boxes are shorter than the full image, so to
get the fastest readout during guiding select "Boxes", obviously for
finding your guidestar use the "Full Image" or "All Images" options.
Exposure Times (bottom):
Use to set the exposure times for the guider boxes and the full
image. You also can pre-define a short and a long default value (the
window comes up with 0.2 and 1.0 sec) and just by pushing the "Set"
button to the right of given value you can make that active. This way
it is easy to switch between a shorter and longer exposure. You can
freely edit the values, but hit "Enter" after modifying the value to
make the change.
Fiber row (up):
Here you may select the fiber you are using for the observations,
and it will display on the full image (lower DS9 panel) a green circle
according to the position of the selected fiber. Also, it will specify
which region of the full image to display in the upper left DS9 panel.
The other DS9 panel (upper right) reads a 100x100 pixel box centered on
the other green region marker of the full image. You can click on it
and grab this one by the mouse (or after clicking on it using the arrow
keys) and freely move it around. When you select a guide star you drop
this second green marker on top of it.
Guide at Offset Position (up-mid left):
If you like to center your target not by making it disappear on the
slit-hole, but rather while you can see it, this button will offset
the green circle fiber marker by the amount specified by the
"RA Offset" and "Dec Offset" values
RA Offset - Dec Offset (up-mid right):
Use this to offset the fiber centroid markers. Since it is using the
tip-tilt mirror to move the target off the slit-hole, specify something
like 3-4 arcsec and only in one direction
Guide on target, Guide on star (up-mid right):
You can select which guider panel to use to determine the centroid
of a star and calculate guiding error.
After offsetting the fiber marker you can select "guide on target" to
fine-center your object or/and to keep it there while you are looking
for a guide star or setting up on a guide star.
Without offset you still can guide on your target, because whenever
it leaves the slit-hole and appears on the guider image it will be
off the center, and so the guider will try to pull it back. Of course,
it than will disappear in the hole, but that is what you want.
If you centered your target on the slit-hole by making it disappear
and you manually centered your guide star in the upper right DS9 panel,
you can just simply select the "Guide on star" - however, for this
centering of the guide star there are better ways:
Transfer Box button (up-mid left):
Once you are centered on the target (either by making it disappear
in the slit-hole and guiding on it that way; or by offsetting the
fiber marker and guiding on the visible star) you can just roughly
center the second green marker circle on the guide star. Just make sure
the guide star is fully visible in the upper right DS9 panel.
At this point "Transfer Box" will calculate the distance between the
centroid of your target (or the slit hole, if there is no offset) and
the guide star, and will adjust the guider marker green circle so that
the guide star will be centered in the upper right DS9 panel. At this
point you can switch from guiding on the target to guideing on a star
by clicking the "Guide on star" button.
Guide at Fiber Position" button (up-mid left):
If you applied an offset to center your target while that is fully
visible, by clicking this button you can take out this offset and move
the target over the fiber, make it disappear in the slit-hole.
By doing so the guider will experience some oscillation which should
dampen in a few guider cycle.
Tip Tilt" row (middle):
The two values show where the tip-tilt mirror is within its motion range.
50 means the middle (50%), and the numbers turn yellow outside of the
10-90 percent range to warn that the tip-tilt mirror should be re-centered
("Recenter" button). For this guiding has to be stopped, and after
recentering the telescope should be moved to take out the accumulated
guider error. After the guide star is close to the center of the guide
filed the guiding can be simply re-started, without setting up the guide
Noname row in the middle:
Sequence number for the guider frames. "Save" will start saving the
guider images, which will be stored in a directory. At the beginning
of each science expousre this temporary directory is cleaned. Guider
frames accumulate here during the science exposure and at the end of
that, after readout of the spectrum all the guider frames are averaged
and saved with the data. These frames can be used to evaluate the guider
performance. The files are stored as hidden files, so filename starts
with a . - but it has the same sequence number and file name as the
spectrum. The g2 prefix means it is the average of the object panel, the
g3 prefix is for the guide star panel.
Focus row (low-mid):
Here you can focus the guide camera. The guider has to be focused at the
slit mask before it can be used. By illuminating the focal plane (push
the "LED" button) and using 0.5 sec exposure times you can see the slit
plate and the tiny holes in it. Select the medium fiber and update the
box images only, and set the target exposure time to 0.5 sec, all the
others to 0, to make it faster readout. Than after "Home"-ing the guider
optics it should be a sharp image of the slit-hole. If not, specify a
small amount of movement (1-2 degrees) in the box next to the "amount"
label and press the "+" or "-" buttons to maake a change in the focus.
Evaluate the image and find the best focus. After focusing turn off the
illumination by clicking on the "LED" button again.
############## WINDOW DESCRIPTION: 2 - Guidercontrol ########################
############## WINDOW DESCRIPTION: 3 - Guidegui DS9 #########################