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I need your help here boys...

Caz

By Caz
in Discussions - Scopes / Whole setups

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Caz

Caz

Posted
Posted

..and girls :D

Collimation again... No groaning please, it may come second nature to some, but to me, its a pain in the "rear" (Modded)! :hmph:

I’ve resisted the need to sort your expertise on this, but I can no longer ignore the fact that I can’t, for some reason, get my collimation sorted!! I’ve successfully collimated it loads of times in the past, why should this time be any blumming different, its really starting to annoy the hell out of me now.

I’m not entirely sure how anyone can help, because at the end of the day, I’ve got to do it myself, there’s a clear sky out there, and I can’t use it!

Anyways, here’s the situation as it stands. The other day I decided to check the collimation, because the previous night the stars looked a little, eeek, not as pin point as they should. So, I thought all it needs is a little tweak to knock it back into alignment, but, no matter how much I tweaked, I couldn’t see the 3 mirror clips, so I tried adjusting the secondary mirror, by turning the center screw clockwise, now I can’t seem to get the secondary central, how do you even tell when its central?…. I’ve tweaked, twisted, turned every possible tweakable bolt, nut and screw on it, and it’s not right.

I’m losing my patience, I don’t even want to go near the scope, because when I do, I get very irritated, and convince myself yet again, its not going to play ball. I’ve even adjusted the primary to see if that makes a difference. Basically, I’ve buggered it up.

What have I done wrong? Anyone? Please?

Caz :D

ps... if anyone points me in the direction of Andy Shotglass, I'm going to spontaneously combust... :D

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iancandler

iancandler

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Ok if you have a set of columation tools its fairly easy.. first of you need to center that secondry.. so with low tack masking tape.. tape a coloured A4 sheet across the tube below the secondry. ( masks off the mirror and makes things less confusing) put your sight tube into the focuser and fiddle with it until its just a fraction larger than the image of the secondry.. adjust secondry until central.. Now dont touch it again..take out the sight tube and paper (carefully so as not to pull off any paint) aim towards a light source and insert the columation eyepiece..now just tweak the primary till everything lines up.. take it out and do final tweaks on a bright star...

I prefer using sight tubes to lasers.. I just dont seem to be able to get the same consistency and accuracy with lasers..

I'm not a pro at columating but have done it a few times now, and this is just what works best for me.. all the best..

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The Warthog

The Warthog

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no matter how much I tweaked, I couldn’t see the 3 mirror clips, so I tried adjusting the secondary mirror, by turning the center screw clockwise, now I can’t seem to get the secondary central, how do you even tell when its central?…. I’ve tweaked, twisted, turned every possible tweakable bolt, nut and screw on it, and it’s not right.

On my Meade, I couldn't see the mirror clips when the mirror was central, but I could move my head just a little and see that the mirror clips were all just off the edge of the secondary by about the same amount. It worked for me.

As much as possible, try to move only two of the three adjusting screws to move either the secondary or the primary. I choose the two that are most nearly left-right and up-down. Then I only have to use the third screw if I run out of adjustment on one of the others.

If you start to get frantic about it, stop, do something else for the evening, and have another go at it tomorrow. Go back to first principles, centre the primary in the secondary first, as best you can, then move the primary so the image of the cross hairs in the primary lines up with the real crosshairs in the collimator. I kow it's possible to get frantic about it, because I found myself hyperventilating once when it just wouldn't work for me.

You've done it before, remember, you can do it again.

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Ambermile

Ambermile

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I know, I know, but I use a single beam 5mw red laser on the big scope (wonderful, made it myself from a gunsight). Getting the secondary lined up with the focuser is the important first step. There's no reason why you cannot mark the centre with a permanent marker - you won't see that bit in the EP anyway. This will help immensely if, for exazmple, your primary clips are not visible like WH's.

Anyway, once the secondary is in line with the focuser it really is rather simple to get the primary right. Do you want my old 1.25" laser?

Arthur

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dabsond

dabsond

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I had the same problem when I installed a new focuser on my 130 newt. Is your primary center marked? If not, that's first thing to do. Have you changed the configuration of the scope, moved distances of focuser or installed new spider? If you can't see the clips, make sure focuser is at complete inward travel. This will increase the the amount of mirror you see. Start by using just your eye through the focuser tube. If you can get a good view of the primary from there then move on to a collimation cap and check again. The idea is line it up just using your eye or cap then move on to a laser or chesire. I suggest you use a chesire first. Final tweaking with a laser comes last. If you do plan on using a laser make sure it is collimated. Place it in the focuser and twist. If the dot moves around on the primary it is out of adjustment. I always use the laser with the tube level and focuser at the 12 o'clock (on top) position. Most laser collimators are back end heavy and do not perfectly fit the focuser tube. This little room for wiggle will throw the whole process off.

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Caz

Caz

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Firstly, can I thank those who have replied, I don't feel so alone on this problem now... :D

so with low tack masking tape.. tape a coloured A4 sheet across the tube below the secondry. ( masks off the mirror and makes things less confusing) put your sight tube into the focuser and fiddle with it until its just a fraction larger than the image of the secondry.. adjust secondry until central..

That sounds like a plan Ian... 8)

On my Meade, I couldn't see the mirror clips when the mirror was central, but I could move my head just a little and see that the mirror clips were all just off the edge of the secondary by about the same amount. It worked for me.

Each time I've collimated the scope WH, I've always been able to see the mirror clips...

try to move only two of the three adjusting screws to move either the secondary or the primary.

That maybe one of the problems, I've moved all three in frustration

If you start to get frantic about it, stop, do something else for the evening

I've been tatting on and off now for 3 days... :D

Is your primary center marked? If not, that's first thing to do.

Yes, its marked....

Caz, could it be that the focuser is either more in or out than when you last did the collimation? That might affect the angle that you are looking at it from as your eye will be closer to / further away from the mirrors.

Oh!... The focusser was out more than last time, that would explain why I couldn't see the clips... :D

Anyway, once the secondary is in line with the focuser it really is rather simple to get the primary right. Do you want my old 1.25" laser?

If my next attempts fail Arthur, expect a pm regarding that 'laser'

Thanks all, off to try again, with hopefully some success....

Caz

Ps... Jamie, I was expecting a *beep* in the place of rear,(Modded) :D:( :( I apologise for my obsenity... :D

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Caz

Caz

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Its ok now Steve, I've done it, the fact that the focusser wasn't fully in, explained why I wasn't fully seeing the clips... :D It could be tweaked a little more, but for now, I'm happy, and its all down to the help from you chaps....

Isn't it always the way, its the simplest of solutions that fix the problem, couldn't see the woods for the trees at one point...

Caz

(one happy :D)

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Caz

Caz

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Ps... Jamie, I was expecting a *beep* in the place of rear, (Modded) :D :D :(

Took ya long enough to notice. (and here was me thinking that i would never get the chance) :D

:D

First and only chance Jamie... Cuz I'm an :D any other time!!

Caz

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Caz

Caz

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So.....when collimating always keep the focuser in the same place, ie fully in or fully out. Is that correct ?

Glad your sorted now Caz

Yep, I put the focusser fully in, it made the world of difference to seeing those 3 pesky clips!!

Caz :D

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