== Making a pointing model using SHOC ==
1. If operating remotely, close all autoguider software first, then close any SiTech software that might be running on lesedi-nuc, as it's too slow to do this exercise via VNC. Ssh -Y into 1ms1 from a machine in Cape Town'''running Ubuntu 16.04.''' Bad things happen if running by sshing from any other version of Ubuntu (though we can't explain why).
2. Open all the usual SiTech software and ready the telescope for observing, then in /home/observer/bin open the programme that connects to SHOC and run astrometry:
sudo ./RunAstrometry
3. '''The SHOC browser should (s) must be closed''', but there's no need to turn the camera off. In the SiTechCamera GUI, select the Latest Image tab, enter an exposure time and click "TakeImage". Check that the image loads (the image scaling can't be adjusted, so if you can't see any stars, make sure you're pointing at stars and tracking, the telescope is focused and that the exposure time is sensible for a 1m). Watch the output in the terminal you used to start SiTechCamera for status info.
4. Make sure that SHOC's rotator is tracking, and on "Config Page 1" of the rotator GUI the boxes are ticked beside "Track PA" and "If PA is out of range, Track PA+-180". On the "Tertiary mirror" tab of the SiTech TCP Focuser GUI, ensure that the tertiary mirror is at the correct angle ("Current Position" = "Final Position (Right Fork)". Make sure the dome is set to "follow scope".
5. In SiTechExe GUI:<br>
6. In the Script window: <br>
Select the Plate Solve Stuff tab, and enter the number of calibration points you want to include in the model (use 150 for a thorough model, or just 40 to get started. N.B it is possible to adjust the size of the zone of avoidance around the zenith (currently set to 5°) in SiTechExe/Config/Change Config!/Mount Params - "Cal Points Pole Distance (degs)), the exposure time (depends on sky conditions, but typically ≤8s), SHOC binning (1) and the delay between the telescope settling and the image being taken (7s is reasonable - note that the dome needs to settle in this time) and make sure "Wait for rotator" is ticked to stop the image being taken while the rotator is getting into position.
Click "Make PointXP Run". The model will start gathering points with the telescope pointing South(if starting from the park position in the East), so you can either rotate the dome to the South before running the script, or press "Play", then "Pause" while the dome catches up with the telescope - you can check the dome position in the "Dome" tab of the Dome Control GUI(make sure it's set to track the telescope). This is the only time during the script that you would need to pause on account of the dome. Note that the way to resume the script is to click "Unpause", not "Play".
The script then moves the telescope from calibration point to calibration point in numerical order, taking an image with SHOC, using Astrometry.net to match the image to a catalogue, determining the position of the telescope, then moving on the telescope to the next point. Things to watch (lots!):<br>
* The Script window, Plate Solve Stuff tab gives a running commentary of events, showing how far it has progressed through the script displayed on the right-hand side, and what is happening (slewing, waiting, counting down the preset delay, saving image, etc). <br>
* The terminal window from which you launched SiTechCamera - it gives a running commentary of what the camera is doing (exposing, transferring data, getting status, etc). <br>* The Astrometry window has a dialogue box showing whether it is currently idle , or busy trying to match coordinates to an image. It then gives the results for each successful calibration (plate scale, rotation angle, number of extracted and matched stars, and how long it took to crunch). If the rotation angle is more that a few arcminutes, check that parallacting parallactic angle tracking is ticked on the rotator tab. <br>
* On Skyview: for each successful calibration, a yellow mark will appear inside each red (numbered) calibration point. Click "Refresh" periodically to keep the two aligned as time passes.
* On SiTechExe: the central "PointXP" button keeps a count of the number of successful calibration points, and the RMS and Peak of the model as it builds.
* The SiTechCamera GUI displays each image. If points are failing to calibrate, check whether there are stars in the images.
7. If an image fails to calibrate, you can return to that point when the script has finished running. Left click on the failed calibration point in the Skyview window. It'll create a pop up saying e.g. "This is future cal point #86" , click on that, then in the blue pop up window that followfollows, click "GoTo". Click "Do a single photo-init" in the Script window. It will take an image with the same camera parameters as were run in the script, unless you first e.g. adjust the exposure time, then click "Save PointXP Script Settings". If the image is solved successfully, a pop up window with a few options will appear - click on "Load cal star" then "OK".
8. To examine and edit the parameters of the resultant resulting pointing model, left-click on the SiTechExe GUI "PointXP" button to open the PointXP window. Note that this does not update while the script is running, so you'll need to close and reopen the window to register new points. A typical pointing model for Lesedi has RMS≤2", Peak≤7". Points can be deleted by clicking on them in the display (deleted points turn red) or toggling "true" and "false" on the "CalPoints" tab, where you can also sort the list of points by e.g. error to match the points on the plot. Phi corresponds to azimuth, theta to altitude. The sensitivity parameter should be low, certainly <300.
9. '''Save the model''' by clicking "Save Text Calibration File" on the Main PXP tab of the PointXP6 window. The naming convention is '''YYYYMMDD_SHOC_Right_NorthUp_150points.PXP''' for a 150 point model made with SHOC on the right-hand rotator tracking the parallactic angle. If you intend to use the model, '''also save it as AutoLoadRight.PXP''' (overwrite existing file) so that it is loaded automatically when selecting the SHOC port. The model file selected for each port is set on the Tertiary Mirror tab of the SiTech TCP Focuser GUI (currently /usr/share/SiTech/SiTechExe/AutoLoadRight.PXP - if you change this, remember to click "SAVE Settings" on the Configuration tab).
10. Close the Script, PointXP6 and Astrometry windows, the SiTechCamera GUI and CTRL-C in the terminal to stop running the astrometry programme. If going back to normal operations, stop all SiTech software and reopen from lesedi-nuc, then do a "sudo systemctl restart lesedi" from 1ms1 and restart the autoguider software.
== Troubleshooting ==