Autofocus Troubleshooting

The most common problem is incorrect Telescope Focal Ratio and/or Focuser Step Size values in the Autofocus Settings dialog. Please refer to the instructions in the Command Reference for information on setting these values correctly.

The built-in SharpStar autofocus only works with stepper motor or servo motor based focusers that have absolute position control. This includes JMI SmartFocus, Optec TCF-S, TI RoboFocus, and RC Optical Systems.

Relative position focusers, such as DC motor focusers like the Meade 1206, are not as repeatable; you cannot simply dial it back to the same position. For these types of focusers, we recommend using FocusMax, a free autofocus utility that is compatible with MaxIm DL. You can download it from

If the built-in autofocus fails, it is usually because the Telescope Focal Ratio, Focuser Step Size, or Target Half Flux is set incorrectly.

If coarse focusing fails, the focal ratio or focuser step size are very wrong.

Watch the autofocus log during fine focusing. It should move approximately 1.5 half-flux units on each step, except near focus. If it is moving in larger steps than this, increase the Focuser Step Size. If it is moving in smaller steps, decrease the number.

If the focuser passes through focus and keeps on going forever, check that the Target Half Flux is at least two pixels higher than the minimum value seen in the log. If this is not the case, the software will never detect that it has passed best focus.

We strongly recommend that you follow the step-by-step procedure in the Autofocus Tutorial. This will help you set up the parameters correctly.