Shoestring Astronomy Support

I purchased a USB Focus Motor Controller hoping to use it for autofocus via the widely used N.I.N.A. imaging platform. I encountered issues loading the FSUSB ASCOM driver (which are described below in case anyone is interested). I did find a couple of workarounds but in both cases have the following problem: N.I.N.A. sees a "Max. increment" and "Max. step" of 1000. This means that total range of travel is limited to 1000 units which is far too small for autofocus where something like 50000 would be more appropriate. When the FSUSB ASCOM driver is connected the ASCOM Device Hub that is part of the standard ASCOM platform distribution it also shows static properties of Maximum Increment: and Maximum Step: as being 1000. I don't know if these are specified in the driver or are ASCOM defaults when no values are specified but is there a way to have them increased? I've tried adding new keys in the ASCOM Profile Explorer but that doesn't help.

Problems and workarounds loading the FSUSB ASCOM Driver in N.I.N.A.
Attempting to load the FSUSB ASCOM driver with 64-bit N.I.N.A. results in a COM Class error which typically happens for 32-bit drivers. It also fails in SharpCap. The driver will load in the depreciated 32-bit N.I.N.A. but with the range limitation of 1000 described above. To load the FSUSB ASCOM Driver 64-bit N.I.N.A. first connect it to the ASCOM Device Hub and then connect N.I.N.A. to the Device Hub Focuser. This again has the same range limitation. There is another possibile workaround described here https://techtalk.gfi.com/32bit-object-6 ... vironment/ which I haven't tried. In 2013 there was some discussion of a combination 32/64-bit driver FSUSBCombo which I downloaded. It also failed to load under 64-bit N.I.N.A. giving a BadImageFormatException.

Unfortunately my skills and tools to write or update these drivers has eroded since I first published these. I would be more than happy to work with someone that has the ability to create a modernized version.

Depending on how many of these units you sell, I wonder whether it might be worthwhile hiring an ASCOM developer and making the driver available at a cost. As there is no other native autofocus solution available Televue telescopes and I would certainly be willing to pay a reasonable price for one. The cost of a Televue Focusmate + USB Focus Motor Controller is $319. One possible alternative I have found is the ESATTO 2" focuser plus a custom adapter at a total cost of around $940 so there is a fair bit of leeway here. I'm not sure how much weight the ESATTO adds.

I'll try a post on the ASCOM developers group and see what happens.

Doug,

Put me down for a "me too" on this exact issue but with Sharpcap rather than NINA. I've been using your driver & control box for years with great success, but when trying to use the autofocus feature in Sharpcap I've run into this same step & increment size issue as well. I've been told by Sharpcap's author that the driver is place to fix it.

I've built a friction coupling and don't need specified Max limits. Any others needing help with this out there? Any luck with the Developers Group?