As he says, the BL box is greyed out, likely meaning that the driver he uses doesn't support it.

@fewayne:

• the nice image is Hys new Analyze tab. You might have to use recent/nightly builds to get that
• Take a look at the settings. You want 'SEP' star detection, and 'Linear' method with 'full field'. Then, under 'Mechanics', look at 'Initial Step Size' and 'Out Step Multiple'. The algorithm will first do STEP sized steps, then half of that. So it should be small enough that it's in the order of your desired accuracy. I use 20. The step multiplier will give you two things: STEP times multiplier should be large enough that the star gets unsharp, but still small enough that you are within the clear slope of the V curve. In addition, it will do the same overhead as backlash compensation. I.e., use 20 and 5 -> initial step is 100. So it will move 200 out, then 100 in, then continue to move inwards in steps of 20. So for your case, that step should be larger than your backlash. Keep those three points in mind, then it should work nicely...