Hello everyone,
I recently removed my primary mirror to check the centre spot positioning etc as I wasn't sure how accurately it was placed to begin with. Anyway, as it turns out it was off alignment by a few mm. After repositioning it accordingly, and reassembling the scope, I proceded to colimmate it. Everything seemed to go as per normal with the colimmation.
Last night I took the scope out to do some viewing and decided to do a star test (first time for this), and something doesn't seem right. When I defocus one way, i get a white ring around a large black disc, (presumably this is the airy disc i have read all about), but when i defocus the otherway, the star errupts in a huge commet tail and stays that way until i have defocussed enough to actually see the secondary mirror and spider veins. Further more when a star is located off centre of the FOV, it looks more like a comet. When i move the scope to make the star rotate around the centre, the tail rotates to always point towards the edges of the FOV. I know my ep's are very dodgy, as they came with the scope, and the tails were always evident (towards the edges), but not to this extreme. Only the very centre of the FOV is without this effect now. I also get what appears to be a reflection of some kind when a bright object is not in the centre. As I move the scope to put the object in the centre, it and the reflection converge to become one, and the FOV fills with background light. Its hard to explain this bit, but its kind of like when someone shines a torch around, you can see the beam, but when it actually passes over you it shines right in your eyes.
I put the colimation tool back in to check it and it seems ok. Centre Spot on the cross and reflection cross behind original coss. I have no idea what is wrong but viewing like this is not good.
.
Any suggestions would be greatly appreciated.