Old 19-09-2009, 12:43 PM
Paul K
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Location: Forbes, Australia
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Problem with focus

Hi all, my problem is I can't achieve focus with the QHY8 on my 12" newt,......I haven't managed to capture a photon as yet....I ended up getting some Proline spacers to use for the correct spacing with the MPCC for the QHY8......couldn't get focus....
I had a low profile focuser, so I changed it to a normal focuser...hoping that I could get enough back
focus....still not enough.......have tried using a 50mm extension....and
guess what......too much the other way....jockeyed the primary around a
bit....not enough play in the cell for that...

The 50mm extender that I have would probably work ok, but I can't insert the camera and fittings far enough into extension tube....as there is a ridge that prevents this from happening...Does anyone know of a fitting that I could use????.....I have
reached the end of my tether....so to speak....so frustrating......

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Old 19-09-2009, 03:44 PM
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DavidU (Dave)
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Hi Paul, what I would do in the short term is to replace the primary collimation screws and lock bolts with much longer ones and replace the springs with longer ones. This will give you the ability to get the primary an inch or two towards the secondary. You will then be able to workout the best camera focuser combo that works for you. Then you are probably going to have to move the mirror cell up the tube by the amount you have worked out.Then for visual work you just use an extention tube for your eye pcs.
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Old 19-09-2009, 08:09 PM
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multiweb (Marc)
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Hi Paul, you won't be able to use the MPCC with the spacer into your 50mm extension tube. Get rid of this extension tube then slide your spacer and MPCC into the focuser directly but secure it on the spacer area or even the MPCC body so you have enough back focus. Don't slide it all inside.
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Old 19-09-2009, 08:35 PM
Paul K
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Thanks David and Marc, I will try out as you suggested Marc....the focus is there, just not intercepting it at the right place..lol....ok then...gotta wait until this front clears....bit too cloudy at the moment...

Thank You..
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