Menu

Simulator for Daytime Testing

2022-03-21
2022-03-23
  • Martin Clayden

    Martin Clayden - 2022-03-21

    Apologies if this has been asked before, but is it possible to configure the Sky Simulator for Ascom to test PHD2 and a mount (HEQ5 Pro) in the day time. It would be highly useful if this were possible; to not have to wait for a dark sky would be great!

     
  • han.k

    han.k - 2022-03-21

    Yes you can simulate guiding during daytime.

    Simpliefied operation:

    Set in the sky simulator the image dimensions the same as your normal guide camera.
    In PHD2 select Sky simulator.
    In Sky simulator select your own mount or the mount simulator.

    Select in the sky simulator artifical sky and one of the option for guding errors.

    Start the sky simulator.

    Han

     
  • Martin Clayden

    Martin Clayden - 2022-03-22

    Thanks Han for your prompt and very useful reply

    I've configured Sky Simulator and PHD2 as you suggest; for the simulator "selecting 20" cyclic 5min & 3" seeing in RA & Dec" and the appropriate parameters for my guide camera. This configuration allows calibration in PHD2 to complete successfully and guiding to start.

    Presently I've selected a simulated mount via ASCOM and I've attached a section of the PHD2 log showing corrections being applied in response to simulated guide errors.

    So, all appears good so far - the simulated mount is responding to guide input. What I'm after testing is how my real mount (HEQ5 Pro) responds and behaves. Specifically, can I detect potential stiction in the mount axes? I think so, but I must admit I'm having difficulty getting my head round this :)

    I'd appreciate your comments and input

    Many thanks

    Martin
    PS
    Also, many thanks for your efforts and support to the astro community - I use ASTAP and the Simulator routinely and life would be very hard without these essential tools

     
  • han.k

    han.k - 2022-03-22

    The simulator is for familiarization and testing of software . A sticky mount is unpredictable so difficult to simulate.

    For my HEQ5 mount I use a PHD2 exposure time of 4 or 5 seconds. Secondly I give some unbalance with the balancing weight such that there is some force on the gears. That's all you can do. An other thing I noticed I have to unlock the RA scale but that is probably specific to my mount.

    Looking to your graph, the 6 seconds is fine but I look like the PHD2 reaction is too strong and it is overshooting. Could be sticky as you indicated. You should be able to achieve guiding withing 2 sometimes 1 arcseconds. Offset of 12" are too much . Maybe the RA agr RA hys and Dec are are too aggressive?

    What I can do is adding square disturbance pattern to the simulator. With this you can test PHD2 "step response" reaction, so a sudden change in the guide star position. PHD2 should react with a fast correction with a limited overshoot. But not too fast because it will overshoot and start oscillating.

    With this you can experiment with the RA agr RA hys and Dec agg settings. The current cyclic error is a sinus shaped and the seeing is random.

    Maybe later today or next days, I will compile something.

    Han

     

    Last edit: han.k 2022-03-22
  • han.k

    han.k - 2022-03-22

    Maybe the RA agr RA hys and Dec agg settings are too aggressive?

     
  • han.k

    han.k - 2022-03-22

    I have created but not released yet.
    While testing I can conclude the following:

    RA agr =70 is okay.
    RA hys =10, is way too low. Something like 70 works better.

    I will release this version later. First some more testing.

     
  • han.k

    han.k - 2022-03-22

    Maybe RA hys is too larger.
    I want to study it a little longer. But these are my current settings of my HEQ5:

     
  • han.k

    han.k - 2022-03-23

    I have used the opportunity to improve simulation for PHD2, but I noticed the settings of PHD2 are not so critical. Your problems must be caused by something else. First thing I would try is some unbalance as indicated earlier.

    Han

     

Log in to post a comment.