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tyler_jrb

tilted secondary mirror?

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hi ive been doing colimation on my scope today and for some reason when I get the secondary nicely centred and into a perfect cirle when looking through a cheshire. then checking the secondary mirror itself it is very tilted. around 4mm gap on one side and around 7-8mm on the other side of the secondary mount.

Its very annoying as I have tried everything and followed several guides to try sort the problem. I have centred the secondary by re-doing the spider veins. I have adjusted the focuser as this is also off. Imagine a horizontal scope then the focuser seems to be pointing to much towards the floor. Ive tried ajusting the screws on the focuser but that doesn't do a lot and looking at the focuser it has a small gap on one side and will not rack in all the way. Looking through the eyepiece holder towards the secondary although it is central and is a perfect circle, you can see that the mount is tilted, again imagine a horizontal scope then looking down the eyepiece holder/cheshire, it is tilted towards the floor. as shown in pictures.

if anyone has any ideas on how to fix the exessive tilting and the problem with the focuser please let me know.

thanks, tyler.b. :)

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Edited by tyler_jrb

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Tyler.b - I think you need to get the focuser square to the tube so it points directly across the tube. It sounds like you may need to shim it using thin metal sheet (aluminium cans are good) or even steel washers. I would do this even if you need to do some work on the tube to make it fit and or use longer bolts to hold it on. The first step in collimation is to get every thing mechanically square first.

Regards Andrew

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Yes as Andrew says if you square the focuser everything else should line up. I posted a bit of info which may help on your other thread.

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