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XOPTIC
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Xoptic is the program which accepts a socket connection from otcom or
videoplay and displays the video images and parameters which are sent
to it.  Originally intended to run on a Sparc2 at the same time as the
CCD control program, it tries to be as efficient as possible and is
written at the Xlib level.  The socket communications is set up to be
non-blocking (so that otcom can never hang waiting for the display)
and uses a handshake to tell otcom when xoptic is ready to accept a
frame.

Xoptic has a lot of controls which are non-obvious because I didn't
want to use up a lot of display real estate with more intuitive
graphical cues, and in keeping with its lightweight nature, will only
accept a limited number of X events per iteration.  Nevertheless it
can be quite adaptable to the user.

<< see xoptic.gif >>

There are three windows across the top.  The left shows the incoming
video frames.  There are always four, corresponding to the four CCD
guide regions.  Even a guide star is not being read out in a region,
the amplifier is still providing a readout and the noise is displayed
by xoptic.  The normal zoom factor for xoptic is 4, i.e. four screen
pixels correspond to one (binned) CCD pixel.  There is a scale of
arcseconds shown in the lower part of this image, which should be
correct if the tel_config file is correct (otcom) or SECPIX?
parameters in the FITS header (videoplay).  Pixels greater than 255*255
are displayed as bright green.

The middle image is the "radar" display.  The left images show the
guide stars in their guide boxes, but the guide boxes can move all
over the CCD if the telescope guiding is not good.  This radar display
shows the center of each star on the CCD relative to the starting
point, and can move quite far compared to the star images in the guide
boxes.  Clicking the left button on this window will recenter the dots
relative to their position at that moment.

The right image is a leaky average of the incoming video.  The leak
time can be adjusted using the "Leak" button below (the left mouse
button decreases the number, the right button increases, and the
middle button sets it to 0 which means don't update the display).  The
leaky average can be rezeroed using the "ZeroAve" button below.

Below the image windows is the "stretch bar".  This is a logarithmic
graph from 20 to 65535.  When the display is autoscaling you will see
a green bar fluctating back and forth with numbers at either end
labelled.  This is the threshold and saturation for the display.  If
you click the left button on the stretch bar you will fix the
threshold value at that value and the saturation whereever it happened
to be.  If you click the right button you will set the saturation
value.  Putting the saturation below the threshold is OK even though
the green bar goes wrong -- it just inverts the color map.

The botton half of the display has some buttons in the middle and two
strip charts on the left and right.  The "Bin" button displays the
current bin factor and the "dt:" button the frame time (they used to
permit you to control it, and may do it again someday).  The "Palette"
button cycles through a B/W, inverse B/W, and rainbow palette.  The
"Auto" button indicates whether autoscaling is on.  Left button
decreases the contrast, right button increases.

The left strip chart shows the seeing FWHM as a function of time.  The
image for which this is being displayed is controlled by the "Img"
button, left button decreases, right button increases, orientation of
0-3 is the usual.  Zero FWHM is at the bottom, the left button
decreases the number of ledger lines (decreases the FWHM at the top of
the scale), and the right button increases the number of ledger lines
(increases the FWHM at the top of the scale).  The middle button
cycles through a display in units of arcsec, arcsec and pixels, and
pixels.

The FWHM samples are shown in green and by default are smoothed with
other samples.  If you want to see the raw samples, the "AveFWHM"
button toggles between raw and smoothed.  There are also occasional
little red ticks which are the FWHM being calculated for the leaky
average, every leak time.  They generally track the green points but
are slightly higher, as you might expect.

The strip chart on the right shows the magnitude of the selected star
as a function of time.  As always, left button decreases the number of
ledger lines (full scale is fewer magnitudes), and right button
increases the number (full scale is more magnitudes).  Clicking the
middle button near the top of the window pushes the scale downwards
(moves the scale to lower magnitudes) and clicking the middle button
near the bottom of the window pushes the scale upwards (moves the
scale to higher magnitudes).

When run from otcom, the magnitudes are based on a zero point provided
in the configuration file filters.def, and should be reasonably
accurate, although no account is taken of airmass.  Clouds are
dramatically apparent.  When run from videoplay, the magnitude
zeropoint is simply taken to be 25, although in principle it could be
obtained from the FITS header entry "PHOTOZP" written by otcom.

The bottom line lists several numbers, in a slightly different
format depending on the size of the window.  In the small size the
labels are: 

  Integration time
  # Frame number
  ( frames_dropped frame_time )
  FW: FWHM of the selected star (unbinned pixels)
  rms: rms motion of recent radar positions (unbinned pixels)
  sky: sky level
  max: maximum pixel