Whether a given image shift causes you a problem depends on its frequency, the amplitude of the rotational component, how long it lasts, and your own observing pattern. Examples include:
- If you are using low power in casual visual observing, and the shift occurs very slowly, say, over a period of hours (e.g., as one side of a house cools faster than the other side) the shift may not be a problem.
- If you are doing a time exposure at high magnification, a shift of a few seconds of arc during the exposure, or an oscillation back and forth during the exposure, may cause distinct errors in the image.
- If your telescope system has a natural frequency of one cycle per second and a Q of 20 for a particular vibration, touching the scope may cause it to vibrate for more than 20 seconds. You have a problem!
- If the same telescope and mount have been modified to reduce the Q to 2-3, or if the natural frequency has been raised to 10 cycles per second, vibrations may cease quickly enough for you to tolerate.
