OSA EXPO notes
Operational Checks for ExPO
0) Visual check in GHRIL that it is ok to move rotator.
[Consult with ExPo team. If necessary move manually in engineering
mode from within GHRIL].
1) Start the default TCS. Make sure GHRIL rotator
power is on.
2) Set up for ExPo
3) Do the usual telescope checks. Once telescope in is computer mode
ROT SKY 300.5
Then do the normal tracking test. Note that the GHRIL rotator
will follow the elevation (you can see this from within GHRIL).
Note that the values shown for Rotator Mount PA are measured in
Leave telescope tracking
4) Switch autoguider control to ExPo
Move the autoguider selector switch (in control room
above lpss85) to position marked [ExPo].
5) Start the observing system on taurus.
Any convenient configuration (e.g. that for standard Cass
instrument with ACAM).
6) Check TCS Staus page for ExPo
Start a web browser. Enter the URL
Should see page like
LAST=21 9 15.184
Azimuth and Altitude are shown in degrees and should
correspond to that shown on TCS info display. LAST is
(Local Apparent) Sidereal Time and should correspond to
that on Info display
Press RELOAD in the browser.Check that the sidereal time
If values don't correspond or don't update, check that TCS and
observing system are running. Then see troubleshooting section
A) TCS status page for ExPo does not update or does not
show values corresponding to those on
i) First check you typed the URL correctly. THen Check that
TCS and observing system are running. Start them if necessary.
ii) Check drama connection from observing system to TCS.
In the pink window
If the TCS info page does not change, drama communications
have failed: perform recovery procedure (a) below.
iii) Check parameter noticeboard. In observing system
pink window get sidereal time using command
ParameterNoticeBoardLister -item TCS.last
Check against TCS info display. Repeat command
and check it has changed (updated every second).
If this does not update, shutdown and restart the
observing system.Then repeat checks from (ii)
iv) Check that the tomcat webserver is running.
You should see the tomcat welcome page. If not
then tomcat is down. Cotact computing group or
reboot taurus using the shut a/c. Restart the
observing system and start checks from (ii).
a) Remaking drama connection to TCS
(i) Simplest way is to shutdown observing system,
shutdown TCS, start TCS and start observing
(ii) To save time one can restart Drama task (TELD)
on TCS. Log into TCS alpha as normal, type
In observing system pink window
If TCS Info page changes, have recovered connection.
TELESCOPE OPERATOR NOTES
For startup, see the DE notes above.
To start applying guiding corrections
AUTO ON 50 50
to stop applying corrections
Expo does not use a derotator, hence field rotates.
I suggest using the ALT-AZ mode of the handset. However
even in this mode direction of corrections will change
ExPo does not have a separate autoguider camera. Instead
it analyses images of the star being observed in the centre
of the field and sends correction packets to TCS.
The ExPo windows PC in GHRIL opens through it's COM2 port
a connection to portserver10 (in the control desk underneath lpss85)
port 1. From there a cable (labelled ExPo) runs to the switch
which must be set at position labelled EXPO.
On the TCS encoders page (PAGE ENC) the latest autoguider
packet recived is shown at the bottom. A typical packet
0050.00 0050.00 0001.01
The last decimal place will change between 1 and 0 when
TCS is receiving updates.
Note that the ExPo PC GUI shows a red light for the port
connection even when it is connected.
In case of problems check
(i) switch is in correct position
(ii) ExPo is sending corrections (have to enable guiding)
(iii) Power cycle portserver10
It seems to be a reproducible problem that when the ExPo
PC is rebooted the portserver does not drop the connection
and so ExPo cannot reconnect. So after PC reboot
(i) Check portserver state using device manager
Right click My Computer.
Choose properties -> Hardware -> Device Manager
Locate Multi-port serial adapters, expand if necessary
Choose portserver10, right click and choose
properties -> advanced
(ii) If connection not shown as connected, power cycle the
At time of writing [Oct 2010] portserver10 is (regrettably) shared
with CANARY, so ExPo and CANARY cannot be used at the same time. In
case of problems it would be worth checking that CANARY guiding is
The rotator is used to maintain corrector plate aligned
with tertiary mirror. The mount pa ranges from 240 deg at
zenith to 320 deg at elevation of 10 degrees.
When the rotator limit cam (as used for INTEGRAL) is
fixed at the 180 deg mark on the rotator plate, it can
never be reached in normal ExPo operation, but does
prevent over rotation and so protects the instrument
It is useful to have a copy of the ExPo PC desktop for
target acquisition. On a convenient linux system
vncviewer -viewonly expo
Note that for this to work, the expo_remote user must
be logged on at the ExPo PC in GHRIL.