Usage of the Schmidt telescope

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Important note: Always save your images to the /data directory, because with the new camera one fits file is around 220MB!
<span style="color:red">Important note:</span> Always save your images to the /data directory, because with the new camera one fits file is around 220MB!

Revision as of 19:32, 17 November 2020

How to start observing

The cooler and the camera of the telescope is always on. If not, contact the support astronomer! There is no filter wheel at the moment.

1. If the telescope is turned off, go to the dome, and switch on the telescope from the control panel. Wait until the oil pressure is appropriate (few tens of a second). Check also the three phases of the electric power (lights with R, S and T, on the control panel). These three light should be on, and the oil pressure should be off.

2. Remove the tube cover. Since the convenient position for removing the tube cover is beyond the software limitations, always use the telescope control panel to move the telescope in this position. Similarly, after removing the tube cover, move the telescope manually (i.e. still using the telescope control panel) to some reasonable horizontal altitude in order to allow the software backends to handle the telescope motions properly.

3. Turn off all the lights and leave the dome.

4. Login to the control computer,, with your own account.

Run eng-schmidt test to see if everything is OK.

rszakats@m9:~$ eng-schmidt test
[  Ok  ] Checking gateway at done. 
[  Ok  ] Checking gateway at done. 
[  Ok  ] Checking MDSNACD bus master at done. 
[  Ok  ] Checking focus motor driver (// done.
[  Ok  ] Checking focus encoder (// done.
[  Ok  ] Checking accelerometer (// done.
[  Ok  ] Checking PSCHTCM server (ALIX)... done.
[ Info ] Checking PSCHTCM status... telescope is busy.
[  Ok  ] Checking dome surveillance camera... done.

5. Start ds9.

Start a screen session. (See Usage of the screen program)

Start the program ccdsh in the screen.

Type status to see if everything is OK.

CCD> status
CCD:      ready # 0 idle
Mount:    ready # 0 idle udec=29.9755 st=342.0044 utau=86.8298 mx=0,0,0,0,0
Dome:     ready # 0 tracking 0x0
Filter:   ready # 0 nothing_to_do
Focuser:  ready # ready
Logger:   ready # 0 idle
Logger:   ready # 0 idle
Logger:   ready # 0 idle
Resolver: ready # 0 idle
Resolver: ready # 0 idle
Resolver: ready # 0 idle
Command:  ready # 0 idle
Command:  ready # 0 idle
Command:  ready # 0 idle
Command:  ready # 0 idle
Keyword:  ready # 0 idle
Keyword:  ready # 0 idle

6. Check the camera temperature: get temperature It should be around -50. Never try to change the camera temperature from ccdsh!

7. Open the dome, and set it to automatic:

set dome slit open

set dome auto on

The mount shuld be tracking the sky, but you can type set mount track on if it was off. The command get dome slit can be used to track the status. Wait until the slit door is fully opened. If the dome is in home position, and there are some lights in the dome area (see the notes at the end), you can clearly see the slit door via the webcamera (see also the notes).

8. Start observing. The telescope can be slewed to any position using the slew command of ccdsh. Individual images can be taken using the acquire command (for testing purposes, for example). Complex series of images can be created via the command sequence. There are many commands in ccdsh that makes the observations convenient (object name resolves using databases such as Simbad or MPC, definitions of favourite and frequently observed objects, visibility calculations and visibility graphs, and so on). Here we refer the full documentation of CCDSH (in English). Please use the command status regularly, both after and before complex operations and/or long image sequences to check if every subsystem operates properly. Wait until the operations complete: if the status of some of the subsystems (e.g. mount, etc.) is busy (displayed in yellow), you might have to wait a little bit until the operations are completed and the telescope system becomes ready to use.

If you have a script, type source myscript in ccdsh. The ccdsh will interpret the script and start to execute it line by line.

9. Important note: Always save your images to the /data directory, because with the new camera one fits file is around 220MB!

How to finish observations

1. Make sure that the telescope subsystems completed their work. Never start shutting down the system before any of the controls is in a busy state.

2. Close the dome slit door (locally from the telescope control panel in the dome area or remotely, using the appropriate ccdsh command), e.g. set dome slit close.

3. You may want to move the dome to its home position. The normal home position of the dome is at azimuth=70 (the slit door looks west-southwest). It is not essential, but recommended. You can use the appropriate ccdsh commands as well:

set mount track off

set dome auto off

set dome azimuth=70 , then wait until the dome moves to its home position (see also the status command).

4. Exit from the ccdsh program.

5. Go to the dome. Put on the tube cover.

6. Move the telescope to a vertical postition. Switch off the telescope.


  • The orders of the procedures in lists above are not so strict, so the observer may alter the order depending on the actual needs. For instance, ccdsh can be started before switching on the telescope. In this case, the status command will report errors for the mount, dome and focuser, but immediately if the telescope is switched on, the status messages also change to ready. Of course, there are obvious dependencies: one cannot switch on the telescope until the main electricity switches are off, or the tube cover cannot be removed (or, more precisely, the telescope cannot be slewed to this position) until the telescope is switched off and so on.
  • Never try to control the telescope movements simultaneously from the telescope control panel in the dome area and from the ccdsh software. If the mount and dome status is ready for both units and the dome status is idle (and not tracking) it is safe to control the telescope from the panel as well. But either the mount and dome are busy or the telescope is started to slew from the control panel, never try to use the another type of control. Note that this is true even if some kind of errors are encountered. If the telescope seems to be stuck or moved to some highly unexpected position, first check the status messages and report these. After, ensure that the controls are released from ccdsh, i.e. check the <codoe>status, and make all of the systems ready by saying set dome auto off, set mount stop and set dome stop. If both the dome and mount are ready, one can go to the control panel and solve the problem manually.
  • The observer can also use the ccdsh commands set dome light 0 on and set dome light 0 off to switch on and off the flat lights in the dome. The light 0 is the fainter one (that is used routinely for taking dome flats) and the light 1 is the brighter one. By switching on the latter one, the dome slit can be seen clearly if the dome is rotated to azimuth=70.
  • The state of the telescope, dome position, the image of the all-sky camera (including the marks of the telescope pointing) and the dome area web camera can be tracked real-time from this location: This web address is temporary, and might be changed in the future. If the brighter dome flat light is on (see above) and the dome is at the home position (azimuth=70), the slit door can clearly be seen via the web camera.
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