Glitching frames on JS but not PsychoPy & Rating scale error

  1. You could have your begin routine code include the following:
hand.setAutoDraw(false);

(where hand is your clock hand object) and then in your each frame code, in the same code that sets the orientation

hand.setAutoDraw(true);

That should ensure that it only appears on the screen after the orientation has been computed.

  1. See here: