Panic stations

[blinky1983]

I had my scope out for 3 hrs cooling so i can rule out that.. I was trying to focus on a star and just as I started moving the focus till the star was pin point it missed it and started to de focus totally missing the pinpoint moment. I have had my primary out for a clean and as always was very careful doing it, Is there a chance I have put the mirror back in the wrong way? What i do see when as close to apin point star is a small tail coming off to one side almost like a small comet... I collimated the scope using my cheshire and the ring is center to the cross hair...

I really cant use the scope knowing that I cant focus properly. Looking at orion and the 4 or 5 stars in the middle of the orion neb was out of focus... AAAAARRRRRRRRGGGGGGGG!!!!!!!!!!

[magic612]

Is it possible you have a pinched primary from the mirror clips? There should not be any tension on the mirror at all. The clips should be slightly above the mirror itself - they are only there to keep the mirror from falling out of the tube should it get turned over completely.

[blinky1983]

is it permanent damage or just acase of loosen it??

[umadog]

Having the ring in the centre of the cross hairs minimises what is known as the focuser axial alignment error. You also need to adjust the primary: the primary axial alignment error. If you don't do this you will get the effect you describe. Follow these instructions: John Reed Home Page Collimation - Cheshire

Pinching the mirror can distort the Airy disk a little but is unlikely to create a comet tail (in my experience). Loosening the mirror clips will return the mirror to normal. No permanent damage.

[blinky1983]

lost me mate lol

[umadog]

I just mean that it sounds like your telescope isn't collimated. From your description of how you've used the sight-tube, it sounds like you've only partially collimated the instrument. The small tail you describe could be due to the primary not being correctly adjusted. Having the centre spot in the cross hairs doesn't tell you whether or not the primary is correctly aligned.

[todd8137]

did you put all the rubber washers back in correct?how old is the scope mines nearly two years the mirror as never been cleaned unds pinched just loosen the 3 clips of a bit is, the mirror under the ep in the right place

[blinky1983]

my secondary mirrior is fine, I washed my primary due to a cake falling into thev ota and got cream on the optics lol, so i just washed, and clipped it back in. what i did not do was mark the mirror so i cold remember which way it was before i put it back in, the collimation was miles off but jst re collimated it till everything was ok ie 6 mirror clips visable on the secondary and the ring centred to my cheshre I has yet still to loosen off the mirror clips to see if that is the problem and will prob get that done tonight..

[umadog]

It doesn't matter if the mirror is rotated: you can put it back whatever way you like. From the description you've just posted it sounds like you've used the sight-tube portion of the combination tool but not the Cheshire portion. The Cheshire is for adjusting the primary and this is likely what's causing your problem.

[ChrisThePuma]

I washed my primary due to a cake falling into thev ota and got cream on the optics

Sorry I had to laugh at this

I hope you get things sorted out soon though.

(what happened to the cake? Did you still eat it?)