SC and Focuser calibration anomaly

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Oberon510
Posts: 79
Joined: Wed Apr 21, 2021 5:15 pm

SC and Focuser calibration anomaly

#1

Post by Oberon510 »

Hi,

I have a recent issue with SC and Feathertouch Focuslynx being out of sync. I am on SC (64) 4.1.12128 and Windows 11 with Feathertouch FTX40 focuser

Steps to produce.
1. Wind the focuser all the way in and use Focuslynx to sync to 0 position. Exit Focuslynx.
2. Start SC and check focus position is 0 - correct.
3. Type in 48590 in SC focuser position and the focuser goes out.
4. Stop SC and start Focuslynx and the position is shown as 51890 (about 3000 difference)

1. Do step 1 above
2. Tell Focuslynx to go to 48590
3. Start SC, connect to camera and check focuser position in SC and it is 51890.

Any thoughts on why there is a disconnect between Focuslynx and SC focuser position counter as it was not this way previously?

Thanks,
Ken
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SC_Focuser.rtf
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Oberon510
Posts: 79
Joined: Wed Apr 21, 2021 5:15 pm

Re: SC and Focuser calibration anomaly

#2

Post by Oberon510 »

Update on the second repeatability step.
1. Do step 1 above
2. Tell Focuslynx to go to 48590
3. Start SC, connect to camera and check focuser position in SC and it is 45417 (not 51890).

Thanks,
Ken
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admin
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Re: SC and Focuser calibration anomaly

#3

Post by admin »

Hi Ken,

the only reason that SharpCap would deliberately show a different value to the raw focuser value is if you have turned on backlash compensation in the SharpCap focuser settings. If that setting is turned on, SharpCap will be trying to compensate for the backlash adjustment size you have set, and make the value appear as if there is no backlash in the system. Basically, with this switched on, the difference between the two could be up to the size of the backlash setting, depending on recent movements of the focuser.

So, I would suggest checking your SharpCap hardware settigns to see if you have turned on backlash compensation and if so, what amount of backlash is it trying to compensate for. If it is turned on, try turnign it off and see if the values then agree.

cheers,

Robin
Oberon510
Posts: 79
Joined: Wed Apr 21, 2021 5:15 pm

Re: SC and Focuser calibration anomaly

#4

Post by Oberon510 »

Thanks Robin,

I got a reply from Optec that they have an option to change the position readout from steps, to mm to microns which I didn't know. I must have moused over the position field and it changed the readout to something other than steps.

Ken
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Re: SC and Focuser calibration anomaly

#5

Post by admin »

Hi Ken,

thanks for reporting back - that wasn't something I had expected at all, so good of you to share, just in case someone else hits the same problem!

cheers,

Robin
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