Suggestions on Nina auto focus

[Phillip]

Dear Developer:

When using Nina for autofocus, we found that there are some ways to make users complete this action faster.

The biggest problem of Nina’s auto focus is the backlash measurement. The backlash measurement results are usually not accurate enough and need to be tested repeatedly. If we can use a new way of focusing, we can effectively improve our efficiency.

The steps are as follows:

1. Move the focuser out of the focus position according to the steps and initial steps set by the user.
2. Move to a certain direction according to the step size set by the user until the HFR becomes smaller and smaller, and get the minimum value (focused position).
3. Continue to move in this direction until out of focus, and accurately calculate FHR during focusing.
4. Reverse movement, according to the step size set by the user, until the HFR matches the previously measured by Nina to reach the measured HFR at the time of focused.

If the initial direction is wrong, we will find that the value of HFR continues to increase, and the trend of decreasing cannot be obtained. At this time, reverse movement is enabled, and N times the user set step length is used as the length of movement.

In this way, the problem caused by backlash can be completely ignored.

Best hope!

[Stefan B]

backlash measurement tool is deprecated and removed. Deemed not reliable enough. The better alternative now is the overshoot method, which does not require a precise backlash compensation value.