Guider Acquisition Failures
===========================

If the telescope fails to acquire a target, this checklist should help
diagnose the problem. To follow this recipe, have easily available the
APF Telescope 1, 2 and 3 desktop. You will also need the APF
Instrument 1 and 3 desktop. On at least one desktop, have a free
xterminal running as user on mainz.

The schematic outline:

#. check for clouds in the web camera
#. slew to bright (2< V < 4) star
#. wait for the telescope to track
#. check mirror covers are open
#. check that the dome shutter is open enough to see star
#. check hatch is open
#. check that the ADC is working
#. check that the guider is at the right focus (4.85)
#. make sure guide camera is exposing
#. check the telescope pointing and home the telescope


Check the sky camera for clouds. Patchy clouds can make acquisition
tricky.

Acquire a star
--------------

Try to acquire a bright star. The easiest way is to use the Skychart
on the APF Telescope 2 desktop. Click on a star at a high elevation,
around 70 or so degrees, and is bright, magnitude 2-6.  If possible,
have it away from any current clouds.

Telescope Tracking and Mirror Cover open
----------------------------------------

Once the APF Telescope GUI reports that the telescope is tracking,
check for the star in the guider. Double check that the mirror covers
are open. The small tab at the bottom right of the APF Telescope GUI
should show a row blue light next to the word Open.

Is the Dome Shutter Open?
-------------------------

If no star still appears and it is clear, check that the shutters are
open. Use the Dome GUI on APF Telescope 1. Click on the Shutters tab
and read the values of the current position of the shutters. Make sure
that the shutters are in a position that allows the star to be
seen. Place the front shutter at 30 degrees and the rear at 120. The
easiest way to do this is with the command ``shutters -f 30 -r 120``
in an xterminal on mainz.

Is Hatch Open, is ADC Working and is the Guider Focused?
--------------------------------------------------------

Next, move to the APF Instrument 1 desktop. Find the APF spectrograph
motor control GUI. Check if the Hatch is open. If the Hatch is closed,
click on the word ``Closed``, select ``Open`` and place the green
arrow or play button.

Check to see if the ADC is in the correct position. The ADC
should be showing an angle that is the zenith distance of the
star. The zenith distance is simply 90 minus the star's elevation.

Below the ADC is the control for the Guider focus. That value should
be 4.85.

If either the guider or the ADC show a red cross instead of a green
check mark, they may not be actually servoing to the correct
position. This easiest way to fix this is to issue the commands in the
xterminal on mainz. For the ADC, ``modify -s apfmot adcmod=pos`` and
for the guider, ``modify -s apfmot guidefocmod=pos``.

Turn on the Guider
------------------

The camera needs to be enabled. In the xterminal window, type ``modify
-s eosgcam genable=true``

Make sure the guider is exposing. On the APF Instrument 3 desktop,
check that the Camera state is Exposing. If the camera is not
Exposing, click the word Enabled and select the Start Camera
option. Then click the green arrow or play button. The command
``modify -s eosgcam gexpose=true`` also will work.

Check Telescope Pointing and Home
---------------------------------

If none of the above works, that means that there is a clear light
path to the guider. The next thing to check is the telescope pointing.
On the APF Telescope 2 desktop, check TelescopeInterface Offset
Control Tab. Make sure that all of the offsets are 0.

To home the telescope, either click the Home button on the
TelescopeInterface or use the command ``slew --home``. After homing the
telescope, park the telescope with the Park buttong or ``slew --park``.