I've cocked up, 1st time collimation

[kniclander]

It might not be anyhting to do with collimation - the barlow will push the focal point outwards - try manually drawing the eyepiece back and if the image gets sharp then that's the problem.

[puregeordie]

It might not be anyhting to do with collimation - the barlow will push the focal point outwards - try manually drawing the eyepiece back and if the image gets sharp then that's the problem.

Before I starting doing any adjustments, I never used to have to goto extremes of moving the focuser outwards even with the barlow, So I'm not so sure of a solution.

I remeber that when collimation is achieved it says (astro babys guide) that to move the focuser out to the extreme when collimating and I think that's what's happened. I don't think you need the focuser out to its extreme when doing this. So might try re-collimating with the focuer only half way out. If you know what I mean.

cheers.

[kniclander]

it is also possible that you've moved the primary too far up the tube in the collimation process which would also push the focal point outwards but i would think that is unlikely. where the focusser is during the collimation process shouldn't matter to the result - it's just that usually you would collimate the secondary with the focusser just far enough in/out to see all of the mirror clips.

[pel]

I bought a laser collimator but found the end-cap method more reliable and easier.

[Freff]

I'm not sure if it's been mentioned, but when collimating keep the scope horizontal when adjusting the secondary with any tools.

Drop one and big sadness could arise.

[pel]

I think Kniclander's suggestion sounds right. Did the location of the primary mirror change significantly during collimation?

[tms48]

You should find that when you use the cheshire to re-collimate the secondary and primary your problems will be solved. I even used the cheshire to initialy centre the secondary. Using coloured cards as shown in Astro Babys guide does makes everything much easier. I did not have the focusser fully out when centering the secondary just enough to let me see the edge of the secondary forming a ring against the coloured card. It will be a lot more accurate when using the cheshire because of the cross wires that can be centered on the primarary donut ring rather than just your eye. Try posting a photograph of what you have so help can be given if needed.

[puregeordie]

Thanks Lads, I'll try and move the primary as suggested and report back. Pain in the bum this like.

Always adjust with the scope horizontal,.. anybodys backs ache when doing this?....... I'll carry on with me knitting!!

Cheers.

[Ford295]

See below for one of my posts on this subject.

My thoughts being very new to all this and liking gadgets and gizmos is this. I have a Skywatcher 200P and thought that things were not right from the off. I brought a laser collamater from Scopes and Skies and when I checked the secondary mirror seemed out. I adjusted it and then set everything to fire back through the target on the collamater and everything looked good to go. When I took it outside to wonder at the mysteries of the universe I could have have the same effect by squinting at the sky. A bit more reading lead me to check the collamation of the laser and it was way out, it was orbiting around the primary mirror like mad. I then went about setting up the laser to be accurate on every point and check the scope again.

In the end I went back to Skies and Scopes (just down the road) and asked them to set it up as is should be and after a bit of tweaking and adjusting it was perfectly setup (thanks Dave).

When I checked the laser at home with my newly set up scope everything lined up perfectly. I now only use mine to carry out the routine alignements from me having to move it around every time I want to view anything.

Moral of the story is, don't assume factory setting are perfect.

Don't blindly trust the laser and ask for help if you need it.

[Siriusmeg]

I feel your pain!! My first attempts at collimating have been nothing short of disaster too. Just about to email my local astro-soc to have them look at it which is a bit embarassing to say the least. But I do feel that having a real person show me will be far better than the best webpage. I used astro-baby's guide and like the fool that I am managed not to read the bit that said just use the cap to line up the mirror clips - with the whole collimator in only 2 were ever visible... I am very encouraged to read that it should be easy to fix by someone with sense!

[onmehedson]

This collimation thing frightens me, I havent attempted it, why isnt there a service and someone can come and do it for me?

I wouldnt worry to much Sanmatt, I also have the 150pl and it only needed collimating twice in the 2 years I have had it. One slight tweak in the first few weeks and another minor adjustment over a year later.

[puregeordie]

Hey people, Who needs a Cheshire or a laser when all you need is an end cap with a hole innit!! its dead easy man.

Finally got it sorted after finding out that the secondary mirror had been adjusted way to much. Loosen'd the fine adjust screws right back and screwed the secondary mirror back up and re-aligned the adjust screws for it, tweacked the primary a little to and looked good. Star tested and also looked really good.

What I found now is that the higher magnification gives a more centered and crisp look than a lower magnification which is rather odd as you would think its the other way round but I'm not complaining about that, could just be my eyes or viewing conditions or something but hey how all done.

Anyways thought I'd bag a few planets before I did the dishes and put the bairn in the shower, this was around 8pm last night. Bloodey ell I was so awe-inspired I didn't get back in the house until over an hour later!

Satrun looked great and could even see details (I think) could see the rings clearly through and make out a few moons around it which looked like it was at around 9o'clock inverted so a few of them must of been at around 3 o'clock, looking at it.

Moved onto mars and I'm sure again I could see the polar cap and some details but not 100% Also found that mars looked better highly magnified than lower magnified.

quickly moved to Venus and could only see half of it due to the crest. blumming amazed.

Time was getting on so had to get back to the dishes.

Really enjoyed it, and again thanks for you help.

Cheers, Si.

[puregeordie]

Forgot to mention I winged to my council about a street light near my back (around 40 meteres away) even though it wasn't really a major headache but a guy came out and had a look and hummed and har'd and he said he would be in touch.

A few weeks later I got an email saying that they would fit a shield on it for me to make my viewing better.

What a result. ****-on!!

cheers.

[pajr777]

Glad you've got it resolved....

[puregeordie]

Glad you've got it resolved....

Ta.