Can you add a feature that would use the FWHM focus tool to measure backlash? I've manually done this twice and it it works pretty well.
I set backlash to zero in ASCOM and focus using the multi-star FWHM in the outward position. Then I focus in the inward position using the same AF tool and take the difference of the two focal points as my backlash. I usually do it 3 or 4 times in a row to confirm my results. It seems like a pretty easy tool to add and might help a lot of people starting out that might not fully understand backlash.
Also...do you plan to add a "final inward step" option in the AF settings so we can experiment with the overshoot method of backlash compensation? I don't think I'll use the overshoot method but wouldn't mind trying it.
Automatic Focuser backlash tool
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'+1' posts are welcome in this area of the forums to indicate your support for a particular feature suggestion. Suggestions that get the most +1's will be seriously considered for inclusion in future versions of SharpCap.
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Re: Automatic Focuser backlash tool
Hi,
in 3.3 I'm adding more support for backlash compensation - you can either specify it as happening in ASCOM or let SharpCap take care of it. I think the idea of measuring the amount of backlash would be a natural extension of that functionality - definitely something for the todo list.
SharpCap already tries to approach the best focus position from the same direction as the focus scan ran - basically if you scan in the +ve direction then goto the best position, SharpCap will go back to the minimum scan value and then move from there to the best position. If that isn't sufficient then you can right click on any point of the graph and get the focuser to either move there directly or with a deliberate overshoot and return.
cheers,
Robin
in 3.3 I'm adding more support for backlash compensation - you can either specify it as happening in ASCOM or let SharpCap take care of it. I think the idea of measuring the amount of backlash would be a natural extension of that functionality - definitely something for the todo list.
SharpCap already tries to approach the best focus position from the same direction as the focus scan ran - basically if you scan in the +ve direction then goto the best position, SharpCap will go back to the minimum scan value and then move from there to the best position. If that isn't sufficient then you can right click on any point of the graph and get the focuser to either move there directly or with a deliberate overshoot and return.
cheers,
Robin
Re: Automatic Focuser backlash tool
I should have clarified a bit more. I'm familiar with how AF over goes past the focus point and comes at if from the same direction but some of the other programs have it built into the settings so it will always do it that when even when manually adjusting the focus position or applying a filter offset. I don't think it really matters if you have an accurate backlash setting or a simple refractor with a quality focuser. I think it might apply to reflectors with a lot of slop. It's just something I wanted to play with to understand it better.
I think the overshoot method isn't a big deal but have seen many post about it so I thought I must be missing something.
I think the overshoot method isn't a big deal but have seen many post about it so I thought I must be missing something.