new telescope. need minor help

[Skwerl23]

I am new to this but I think I'm grasping it quite well. Anyhow I have 2 questions.

Fyi. I have an Orion xt8

1. When I culminate the secondary mirror. And I'm setting the angle or rather the three set screws. How tight is too tight. Its hard to tweak these little guys. I got it but I feel like I might be digging into plastic and after a year these screws.would seem useless.

2. I used it for the first time 2 nights ago. And when I used it all stars were fuzzy. But not in the out of focus way. More of a "star flare" way. They had little offshoots. Kind of like the streetlights through a windshield do. Bad thing is I used the scope almost immediately after taking it outside. Would these distortions be caused by mirror temp or dirty eye piece or what? The.mirror wouldn't have been more than ten degrees from outside temp.

Thanks for any help. Please ask any questions if you have em.

[Islander]

The spikes are probably diffraction spikes caused by the secondary spider and quite normal.

If you think that the primary screws are too far in then you can always loosen them off in equal amounts until you're happier with the tension and then recollimate the scope.

[brantuk]

It sounds to me like you have some screws too tight. Maybe the three collimation screws on the secondary, or maybe the three locking screws on the primary. This will cause either mirror to distort and the image will exhibit the views you describe.

The primary locking screws only need to be snicked up finger tight to hold the mirror in place - but not too tight to pinch the mirror. The scondary screws will work easier if you loosen the central screw a quarter turn. Don't undo it completely or the secondary will fall off and hit the primary mirror wrecking both.

Do any adjustments with the tube horizontal to minimise damage if this happens. A good upgrade is to get "Bobs Knobs" which will make secondary collimation much easier. Hope that helps

[Skwerl23]

Ill test primary tightness. I did it by hand but I am known to caveman things.

Also the secondary screws aren't hard to culminate persay. My point is what's to tight is there a more thuroifh video on hoe to align this part of the mirror (not distance but angle) the center screw is impossible to turn when the 3 outer screws are tightened.

Oh I had one last question. How important is precision culmination. Say is 99% good enough?

[Skwerl23]

Collimate* lol

[Skwerl23]

After a few minutes know Google I have a feeling islander.is right about the diffraction from the spider. How do I minimize this?

[Moonshane]

^{don't know what scope you use but it's almost certainly that you did not allow enough time to cool. the secondary adjusters should be just a tas more than finger tight - although finger tight is good enough really.}

^{let it cool more and I suspect your issues will disappear largely.}

[brantuk]

It's hard to measure 100% collimation - but a star test will reveal if it's out. Focus on a star - then defocus "slightly" one way, then the other. At each end you should see the same airy disks perfectly concentric around the star. If they aren't concentric then it's out of collimation.

You will still get 4 diffraction spikes caused by the spider though - even when collimation is bang on - but it shouldn't be "fuzzy". You might have been using too high a magnification. As mentioned above - you should allow 30-60 mins of cooldown time and things should improve as the scope comes to temperature. Also note the sky conditions - if there's a "haze" or cloud in the air then it may look fuzzy.