n.i.n.a autofocus is currently incompatible with focusers without steppers. Can you add code to emulate stepper motors

[Benjamin Schulz]

When faced with a focus motor without stepper, like for example, a jmi focus motor for an sct and a shoestring adapter to usb, n.i.n.a can not use use autofocus.

The application astro photography tool can, in this case, emulate a stepper motor and attempt to autofocus.

This should not be too difficult to implement it in n.i.n.a, I think.

Simply introduce certain timings where the motor is set to run as a “step”.

[Stefan B]

This is about relative focusers right? This is already implemented in the develop branch and is available once the 1.11 nightlies start.

[Benjamin Schulz]

Well, I do not know exactly what you call relative focuser. What I have is this device:

http://www.store.shoestringastronomy.com/User_Manual_FCUSB.pdf

In the configuration, one can set motor speed, pulse frequency and the pulse time. And then an astro software can connect through ascom and issue a pulse.

What I know is that n.i.n.a currently can not use it for autofocus.

Even though the device has an ascom driver and I can command it via astro photography tool, whose autofocus and hfd algorithm unfortunately has entirely different issues that would claim focus when it is still unsharp (regardeless of the motor used): https://aptforum.com/phpbb/viewtopic.php?p=21850#p21850

If I could use my focus motor soon with n.i.n.a I would like to try it out.

[Dale Ghent]

A relative focuser uses DC voltage and timing to drive the motor. Because the motor does not offer any feedback reference like a how stepper motor does. The controller must use a combination of voltage and time to guess how far it has driven the motor since its previous position… which is why it is called relative.

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[Benjamin Schulz]

Well, in the device that I have, one can set motor speed, pulse frequency and the pulse time. but not voltage.

So I do not know if the implementation you made supports my device. It has a 32 bit ascom driver, however.

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[Stefan B]

As long as the driver is compliant to the ascom specifications it will work. From my understanding your ascom driver is reporting as being a relative focuser otherwise it would already work. so once 1.11 is there you should be able to use it

[Victor S]

I also own the FCUSB focuser (driving a JMI Motofocus) and am eagerly awaiting this capability. For my part, I tried using both of the two different ASCOM drivers for FCUSB that are offered on the Shoestring Astronomy website. One of them appears to be 32 bit and so fails when I try to connect to it with the message “An ASCOM driver interop exception occurred…” When I try to connect to the newer FCUSB ASCOM driver, it fails with the message “FCUSB/FCUSB2/FCUSB3 hardware not found. Please make sure it is plugged in.” (the device is plugged in to the USB port). I look forward to trying to use this device with 1.11.

[Marek SK]

have this been resolved, I have similar issue with this focuser driver?

[Dale Ghent]

If the focuser driver cannot find the hardware, that is an issue with the focuser driver, not with NINA.