Autofocus errors

I don’t think this is a support ticket so wanted to ask in the forum. I consistently, more often than not, have problems with the autofocus. I get good vcurves when adding a vcurve or setting it up but I consistently get errors along the line of maxim iteration to find start hfd reached and maxim iteration to find near hfd reached while doing a sequence.

I really don’t know what these mean or what I should be looking at tweaking in the settings. Sometimes it will work great and sometimes it just nothing but give errors.

Any clarification on these errors and where to start looking would be greatly appreciated.

Eric Horton

Hi Eric,

in Voyager error is reported in monitor in RED and warning in YELLOW. RED error mean stop of actions. YELLOW means a series of retry will be done or just a warning about something that not goes in the right way but is not blocking. There are other colors but not for what you asked.

HFD not reached is a WARNING, the RoboFire read an HFD value too much different from the one expected and calculated before to send the focuser at request point.

Percentage of HFD allowed can be configured here ( Max HFD Error for Algorithm to find Top, Start and Near Focus:):

How to reduce the warning (after 3 retries the action will be aborted , in the sequence mean no focus):

  • Default value of the previous mentioned parameter is 5%, depends on your system you can go up to 12%. Put directly at 12% not more
  • your focuser have a slippage, check the weight / mechanics and screw up the thing include friction if you have
  • your focuser have a big backlash not included in the RoboFire Settings, set the backlash
  • your focuser have backlash and you have configured in driver but also in RoboFire (only in one place and better soluton is in RoboFire due to the AI support)
  • you have configured backlash in the same direction used for the focus (direction for focus at gravity , backlash direction against gravity)
  • your focuser motor have discrete interval of position with granularity greater than 1, this must be asked to the focuser support. Use this parameter to set the minimum discrete interval Focuser Position Check Tolerance [-/+] : AutoFocus Setup - Voyager Wiki
  • seeing or wind condition, tracking, shape of star from optic do not allow good recognition of stars

The last, true if you done a mistake in first light wizard or have changed optic or added optic elements or changed the focuser or gear of focuser:

  • VCurve in RoboFire settings is not good, redo the first light wizard

I hope this help.

All the best

1 Like

Thank you. I see some areas that can use attention. I will work on that tonight when it gets dark

It took me about an hour but I was able to get a curve initial vcurve and then was able to consistently get the focus to run. Had to change some parameters but finally got it. I appreciate the clarification and assistance.
Eric Horton

Hi Eric,

usually run a vcurve is a question of 5/10 minutes. Thanks for feedback.
Remember you have remote support for this kind of task, We can do togheter.

All the best

Thank you. Seems to be working for now. My skies were not the best last night and that caused my hfd values to be a little higher than normal but it did focus every time it ran. Thanks again for the assistance