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Focuser trouble when NINA starts

Stefan Berg Nighttime Imaging 'N' Astronomy (N.I.N.A. / NINA) Focuser
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ValeryL avatar
ValeryL avatar

Hello,

I’m new to NINA (was using ASIAIR before), I was able to connect and set everything and to perform two nights of imaging.

Here is my issue, the last two times I turned all my equipment on, my focus was lost (I mean stars wereway out of focus, only polaris appeared as a really big circle). I figured it when trying to polar align using TPPA, it could not plate solve of course.

When I was using ASIAIR (since then I did not touch the focuser or the scope) my focus was almost perfect on the next day as expected.

The second time it happened, the focuser started beeping when it was turned on, but it was not at limit (it was arround 32000 step, max is 60 000), so i disconected it and reconnected, it did not beep this time, but as for the first time, focus was lost. Also I don’t think I was in the mechanical limits of my focus in/out movement.

The two previous nights of imaging before it occured gave me good sub exposures, in focus. The sequence I used had a trigger on autofocus (if 10% HFR increase).

I tried my best to understand the issue, I checked on multiple ressources but could not find a similar situation.

Some people have issue with beeping focuser but they all said because step value was incorrectly set a 0 which is not my case.

Some stated that autofocuser screw on the focuser shaft were loose, but as I said I did not touch/change my autofocuser set up, and autofocus runs are OK.

Temperature was kind of the same from the end of the previous night to the begining of the next one, and also focus difference was too much.

I’ll check which driver I used because some people state that switching from native to ASCOM or the other way arround helped.

Now that I wrote this post I’m also thinking that it’s possible that my trigger autofocus was in a parent container of the one with the trained flats exposure. But if an autofocus was triggered with the flip/flat panel closed, the autofocus would have failed after two or three exposure (no HFR difference because no stars) and focus should be a little of but not as much as I experienced…

Also, when i calculated the filter offsets, I accepted the values but did not check the relative values, might this be the issue? the filter offset worked well during imaging sessions.

Well that’s all I can think about, any ideas would be appreciated !

andrea tasselli avatar
andrea tasselli avatar
You don't say much 'bout the equipment you use so I'm inferring that you are using a FW and mono/OSC camera. If it is so then the default position of a FW may be the reason you are way out of focus since the last time you used the scope. As for the beeping no idea why it does what it does but in general that might be an issue with its calibration so check it out.
ValeryL avatar
ValeryL avatar

andrea tasselli · Sep 3, 2025, 01:28 PM

You don't say much 'bout the equipment you use so I'm inferring that you are using a FW and mono/OSC camera. If it is so then the default position of a FW may be the reason you are way out of focus since the last time you used the scope. As for the beeping no idea why it does what it does but in general that might be an issue with its calibration so check it out.

Hello,

Sorry about the missing equipment description :

Minicam8 (monochrome with integrated filter wheel), my filters are :

Dark/lum/R/G/B/S/H/O

Default position fot the FW, well I did not know it existed, is it the position at connection? Where to change it?

About EAF calibration, what do you mean? is it within NINA of directly in the ASCOM driver window?

Thanks

andrea tasselli avatar
andrea tasselli avatar
The ASCOM driver defines the filters and their relative position in the wheel (assuming standard wheel behavior here). NINA, without fail, will start with the filter in the 1 position and not really sure you can change that. My FW ASCOM driver wouldn't let me do that, for example. You calibrate your EAF (again, YMMV as I have most likely a different hardware) mostly through the supplied software that comes with the EAF, which is to say it defines the range in steps units between the lowest safe position to the highest safe position of your focuser range.
ValeryL avatar
ValeryL avatar

ValeryL · Sep 3, 2025, 01:51 PM

andrea tasselli · Sep 3, 2025, 01:28 PM

You don't say much 'bout the equipment you use so I'm inferring that you are using a FW and mono/OSC camera. If it is so then the default position of a FW may be the reason you are way out of focus since the last time you used the scope. As for the beeping no idea why it does what it does but in general that might be an issue with its calibration so check it out.

Hello,

Sorry about the missing equipment description :

Minicam8 (monochrome with integrated filter wheel), my filters are :

Dark/lum/R/G/B/S/H/O

Default position fot the FW, well I did not know it existed, is it the position at connection? Where to change it?

About EAF calibration, what do you mean? is it within NINA of directly in the ASCOM driver window?

Thanks

Hi,

Update, yesterday the focuser did not beep at connexion, and focus was almost good.

I compared focuser step position with previous session logs, and it was the same.

One think i noticed, is that indeed first filter was the dark one, and filter offsets were set like this :

Dark O

Lumi 29 000

R 29 something

G 29 something

(because of course did not calculate filter offset for dark filter)

So could be that, at NINA start, when it came back to filter 1 : Dark. it tried to apply the offset difference between last used filter and Dark (so ~ 29000 steps difference..)

Anyway, I changed my offsets for relatives values (0 for luminance) and also 0 for the dark filter. I also took note of the focuser position for next start of NINA.

Geert Vanhauwaert avatar
Geert Vanhauwaert avatar

Hello

Could it be that the first time it tries to focus with the dark filter? if it does not find any stars may be it runs away…

I have no issues with N.I.N.A. and focussers, they normally wake up at the same place where they left the night before.

ValeryL avatar
ValeryL avatar

hi,

My Lum filter was set as the one for autofocus run.

But still, my filter in position 1 is the dark filter, and when I start NINA and connect the filter wheel it is the dark filter that is active.

Further more, when I calculated my filter focus offset, i did not include the Dark filter in the process and I did not check “relative values”.

So might be that when I reconnected the wheel and took a first frame (for alignement) NINA applied and offset between Dark and Lum filter of 29000 steps…

That’s my best guess for now.

I changed my offsets to relative values with 0 on lum & dark, I did a test and this seems to have fixed the issue..

I’ll confirm after tonight as it seems I’ll have clear nights this week end :)

Thanks for your message,

Clear skies

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