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Unreliable Homefind with OK3


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#1 w0mbat

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Posted 03 January 2014 - 07:03 AM

Hi all,

I have the standard OK3 focuser that came with my N10 astrograph. I am finding that the Homefind routine only works sometimes. I have used the focus control in Autoslew and also ACC. Both software routines do the same thing. I press the Homefind button and the focuser slews all the way inwards and then keeps running. The position indication number in whichever software I am using keeps changing but the focuser is no longer moving. It appears to have reached its inwards limit.

Occasionally it does work and reverses out 2mm and resets the display to that value as expected.

I am concerned that the motor continuing to run while the focuser is not moving may damage the mechanism.

Surely the focuser has limit switches at the end of its travel?? If so it looks like they only work sometimes or else the focuser stops moving before it reaches the inwards limit.

The only thing I can think of to try is to increase the shaft pressure with the adjusting screw but I am not willing to do that yet in case I am missing something else.

Any ideas?

Regards,

Ian


ASA DDM60Pro, ASA N10 Astrograph, Orion ED102T CF Refractor, Canon 60Da DSLR, Sirius 2.3 Metre Observatory, WIN10 Pro 64bit.


#2 nakbrooks

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Posted 03 January 2014 - 01:28 PM

I have the ASA secondary mirror focuser on my Cass 400 but experienced the same problem at first (using ACC). Turned out that the default settings had it focusing far too fast. ASA did a remote control session and adjusted all the (undocumented) settings and it works fine now.

No point in me giving you my settings as I assume they are OTA and focuser specific. Suggest you ask ASA for a remote session.

Nigel
Nigel Brooks
Stratis Observatory, Hautes Pyrénées, France.
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#3 gmalits

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Posted 03 January 2014 - 04:02 PM

Hello Ian,

 

yes there is an endswitch inside!

 

i had the same problem with my OK3 an it turned out, that the whole focuser was not properly centered on its base and the barrel streaks the base, so the barrel could not reach the inner end position, therefore the motor keeps on turning and turning ....

 

what did i do:

i unmounted the focuser - 3 Hexscrews - 120° at the base - an mounted it back centered  .... ready

 

after that, fresh collimation of the N10 is needed.

 

don't touch the pressure screw, only in case you can't get reproducible focus positions.....


Edited by gmalits, 03 January 2014 - 04:15 PM.

regards, Gerald
---------------------------------

DDM85S / 10N-OK3 f3.6


#4 w0mbat

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Posted 04 January 2014 - 06:34 AM

Thanks for the suggestions Nigel and Gerald. I have visually checked the focuser barrel and it appears to be centred. I think I will contact ASA support directly and see what they suggest.

Ian


ASA DDM60Pro, ASA N10 Astrograph, Orion ED102T CF Refractor, Canon 60Da DSLR, Sirius 2.3 Metre Observatory, WIN10 Pro 64bit.


#5 Konihlav

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Posted 09 January 2014 - 09:02 AM

Ian,

 

I had similar "problem" first night out... it turned out I had to just slightly tighten the pressure screw... my problem was - focuser was pulled completely out (at 30mm) and with camera mounted (under a load) it was not able to pull in to zero (or 3mm) position as there was not enough pressure.

 

My OK3 standard seems to be centered well and the pressure screw was the only thing I had to touch ever on it...

 

Pavel



#6 w0mbat

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Posted 26 February 2014 - 09:13 AM

I reported this issue to ASA support and they have told me they believe that "there is a problem with transferring the settings from the software to the controller box". They are working on a solution which is expected soon.

Ian


ASA DDM60Pro, ASA N10 Astrograph, Orion ED102T CF Refractor, Canon 60Da DSLR, Sirius 2.3 Metre Observatory, WIN10 Pro 64bit.





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