calling all newtinian collimation gurus

[soggybongo]

went and bought a cheshire collimator as pictured below as i did not trust my lasor collimator and was stupid enough to buy it in the first place, cleaned both primary and secondary mirrors using this tutorial

then collimated them with astrobaby's tutorial. http://www.astro-baby.com/collimation/astro%20babys%20collimation%20guide.htm

hows it look with your trained eye??????

[Tinker1947]

Try a star test, that's the best way, looks ok to me by the way..

[Catweazel]

Looks good enough to me, but like Tinker says, try a star test if you want perfect collimation

[LukeSkywatcher]

Looks good enough for visual observing. Its off slightly but the eye wont detect that.

[soggybongo]

Thats one question i meant to ask, when star testing do i just slightly de-focus or rack quite a way out. The reason for asking is i carried out a star tested last night and defocued from what looked like a pipoint (in focus) star to say a 2cm size star and got the pinched mirror pic on astro baby's website, but if i very slightly defocus i can see the rings around the star showing perfect collimation.

i removed the primary thinking i had tightened the clips down to far but the are loose, when i say loose i can easily place a playing card between the mirror and clip. The clips are made of a very soft rubber so have a little give in them

[soggybongo]

Looks good enough for visual observing. Its off slightly but the eye wont detect that.

when you say it's off slightly, can you explain where mate?

i'm new to this

[Starlight 1]

It look like its set for a fast tube 4.7 /5 may be.

[soggybongo]

The scope is an LXD75 N-6AT (f/5) used more for photography than visual. aint ideal i know but i just want to get the best out of it.

[Gomtuu]

Don't chuck your laser away - you can use it with a Barlow to fine tune your collimation, even if it's a poor one.

Mine's a fast scope (F5) and looks like this down the collimator (the Cheshire looks identical to mine btw) :

I only did this a couple of days ago, and like you I wasn't sure if I'd got it right, so I posted the picture.

[soggybongo]

Don't chuck your laser away - you can use it with a Barlow to fine tune your collimation, even if it's a poor one.

Mine's a fast scope (F5) and looks like this down the collimator (the Cheshire looks identical to mine btw) :

I only did this a couple of days ago, and like you I wasn't sure if I'd got it right, so I posted the picture.

your pic look similar to mine, the north/ south line of the crosshair(blurred one) is slightly offset to the left compaired to the vivid thin black line within the center spot, so it looks as if the thin line is spot on but the blurred line is off if you get me???

[Gomtuu]

I know what you mean. I was very confused as to which crosshair image to use initially. I suspect it should be the blurred one, but the damn thing came with no instructions!

[LukeSkywatcher]

when you say it's off slightly, can you explain where mate?

i'm new to this

I wish i could but i am not expert. Its not something i worry about too much. It just looks off centre to me.

I'm sure more experienced folk here will set you right.

I will say this though:

Too many people get too hung up on collimation and really think it is a HUGE problem. It really isnt that big of an issue unless you are seriously into astrophotography. Then it needs to be 100% spot on. For visual observing...................it really does not come into play. Unless your scope has taken a big fall or knock then the collimation should be pretty sweet from the retailer (not always though).

Your collimation to me looks fine for visual.

For uuber perfection when you look down the scope, this is what you want to see:

It doesnt matter if the crosshairs are offset from the 12,3,6,9 position (as shown here).........................once everything converges DEAD centre.

The main thing is that if you are happy with the views......................thats all that counts. "Seeing" will mess up the views a lot here in the UK and Ireland. You have to learn that and know its not down to bad collimation.

Paul.

[LukeSkywatcher]

your pic look similar to mine, the north/ south line of the crosshair(blurred one) is slightly offset to the left compaired to the vivid thin black line within the center spot, so it looks as if the thin line is spot on but the blurred line is off if you get me???

That to me looks just about perfect.

[Catweazel]

Looking at Paul's picture he posted of the perfectly collimated scope, I have found that it's almost impossible to see all 4 mirror clips through a cheshire! What you see will never look like that picture; you would be mucking about for ever trying to get there. Maybe an expert could train you to do it? but really, it's not worth worrying about; even for AP it wouldn't need to look that neat

[umadog]

If your secondary is too small then you won't be able to see all the clips. Not everything should be concentric, however: http://www.cloudynights.com/item.php?item_id=2677