Add preset focuser positions

[Niccolò Coli]

Suggesting to add a preset focuser position llinked to profile

[Ruediger]

This function is absolutely needed, because without you are not able to move the focusers to an initial position, from where you can start an successful AF run.

Without you always need another program or manual interaction. This stored focuser positions must be accessible from within sequence, or at least at beginning of a sequence. This could be an option for AF option in sequence. e.g. “Move to position xyz at beginning of sequence”

‌

[Stanley Dimant]

Why do you need to move the focuser to an initial position? When you boot up the system the focuser normally stores its last position, which should be close to your focus point already. The only scenario where this would make any sense is if you move the focuser to 0 every time you stop imaging. But we cannot guarantee that.

When you manually crank the focuser position without adjusting the position in firmware, the focuser boots, it tries to move to position X through NINA and rams itself against the drawtube or to the boundaries, causing potential mechanical damage to the focuser and electronics.

Since mechanical and electrical positions are independent with focusers due to unknown external influences, moving the focuser to an absolute position on start could lead to catastrophic failure of the equipment.

‌

[Ruediger]

Hi Stanley, this is not valid for my focusers. All three focusers have a sensor system and calibrate absolute perfect to a repeatable zero position by 0.001mm. So positions are absolutely repeatable and absolute precise. Since I have take down the tubes after imaging, all focusers move back to zero park position.

‌

[Stanley Dimant]

For the vast majority of users I’d argue this is not the case however, adding such an option can cause trouble. Maybe in the Sequencer rework there will be a move to absolute focuser position item people can use in their sequences.

[Ruediger]

A workaround via sequence could be to rewrite the sequencer in a way you can integrate scripts at any point. Also to connect/disconnect equipment. Then I could directly access the focuser via script: Disconnect focuser, set position via script and re-connect it.

‌

[Stanley Dimant]

A major sequencer rework is in planning/work for 1.11.

[Ruediger]

Great. That's real good news!

Thank you!

[Dale Ghent]

This was something that I had intended to submit to 1.10 some months ago, but time ran out. It would be quite useful as my CFZ is somewhere around step 25,300 on one telescope and 29,500 on my other. Given that I have a mobile setup, I basically start out each time with the focuser racked all the way in at step 0, as necessitated for transport and storage. Right now I just manually command the focuser to move to that step # as a part of my process of starting up for the evening before kicking off any sequence.

I envisioned this as being both a global and per-filter setting under Options > Equipment > Focuser, where one can set a step number and a percentage. The logic would consider these settings before any AF operation, where the focuser’s step position should be within + or - the specified percentage of the specified step # and move the focuser to the specified position if it were outside of that defined range before starting the AF operation.

[Ruediger]

Hi Dale, Hi Stanley,

Dale, I totally agree to what you state. I am also of the opinion this feature request should not be dropped. Other functions are also potentially dangerous. I don't know any focuser which gets damaged when exceeding zero point. Also the people should know what there are doing. Sending an ALT AZ command which collides with the pier is by far much more dangerous than a focus move.

Therefore I still vote for implementing this feature request. Thank you!

[Stefan B]

This will be part of 1.11 as part of the new sequencer. There you can set up a startup sequence item to move the focuser to a specific position. Furthermore when this startup is used as a template it will be preloaded on startup. The first iteration of this new sequencer will soon be available through nightly builds, therefore marking this as resolved.