autoguiding problems with meridian flip

Discussion in 'Image Capture' started by RFA, Jan 9, 2020.

  1. RFA

    RFA Standard User

    Joined:
    Oct 6, 2018
    Messages:
    21
    Location:
    Orciatico, (PI) Italy
    Hello colleagues, in my remote observatory 1150 km far from where I live, I am using MaximDL Pro with a Mesu-200 mount with SiTech-II controller; the observatory is controlled by software RICERCA which allows automated observations.
    Instrument: ASA 12" Newton, CCD camera with OAG Starlight guiding camera.
    When RICERCA (RIC) starts the observation it initiates in Maxim the calibration, after that starts guiding. The guiding works ok within +/-0,5 arcsec. After meridian flip guiding is much worse and oscillates within +/-5 arcsec. The guide star is not lost.
    Aggressivity 6 / 8 adjusted
    I am asking for hint and suggestion, where I can search for the reason for this strange behavior.
    Thanks in advance, rfa
     
  2. Sreilly

    Sreilly Cyanogen Customer

    Joined:
    Oct 10, 2014
    Messages:
    236
    One thing that comes to mind is scope balance and wire wrap. I'm not familiar with your equipment but I balance my system so that it's slightly heavy to the east. That keeps the mount's gears engaged to take up any backlash. Wire wrap can be a real issue. I use a flexible wire mesh warp on my cables to keep them in small bundles and I removed my clutch knobs as they could be catching/snag points and instead just used the allen head bolts that fit flush. Wire management doesn't have to be pretty but it has to be right and using a wire wrap that stays pliable in your observatory's environment is important.

    Is mirror flop a possibility? Have you checked the gear mesh on both axis? Rotator backlash? Just check it over periodically. How much of a temperature change do you see between seasons?
     
  3. RFA

    RFA Standard User

    Joined:
    Oct 6, 2018
    Messages:
    21
    Location:
    Orciatico, (PI) Italy
    Hello Sreilly,
    thank you for your reply. I forgot to give more details: The Mesu-200 mount is a friction driven mount, there is no gear, no backslash. Since the holding torque is very limited, the scope has to be very good balanced including cables. To the scope are going only two cables 3x0.75mm² 230V high flexible cable and one USB industrial high flexible cable - that all. All what I have tested - there is most preferably no influence by that.
    But many thanks for your hint.
    rfa
     

Share This Page