Collimating a SkyWatcher 8" Dob

[Stu Ward]

Bought a Laser Collimator today to give the Dob its first service

Things i noticed

When placing the Collimator in the 1.25", there was still a bit of slack and when tightened up it could still shift. So i placed it in what i thought was a good position.

Adjusting the Secondary to get the laser in the donut.

The 3 Allen key bolts were so tight they would not loosen.
So i brought the laser into the donut by adjusting the 4 vein knob, is this OK ? The laser was on the edge of the donut, try as i might, i could not get it bang in the middle


Adjusting the Primary

Very Straight forward and no obvious issues. After it was done the secondary was still lined up fine


If i have done anything wrong please let me know

[multiweb]

You'll need to get those 3 bolts loose so you can tilt the secondary.

[Stu Ward]

OK so i got em undone and had another go

What really worries me is the slack that is between the 1.25 fitting and the Collimator.

How do you know if you are aligning properly ?

[Vanda]

Which one did you buy Stu? Slack is not good. (hopefully someone may have a solution for you)

[Stu Ward]

I bought the $59 GSO Laser Collimator from Andrews Communications

[JethroB76]

You might need to wrap the collimator in something (contact?) to make it fit the focuser better.
And if you loosened the spider vanes at all you'll need to tighten them back up.

[erick]

Yep, the stuff you used to put on the school books - well we did in my day! "Contact". Try one wrap and see if that takes up the gap between the collimator and the 1.25" adapter. If that doesn't work, try two wraps. I have found one wrap of a GSO collimator was sufficient. You want it nice and snug, but you don't want the contact on only one side - ie. not half a turn or 1.5 turns.

[Stu Ward]

Thanks Eric

So it must be a common problem ???

Now where do i find "Contact" !

Stu

[wavelandscott]

Most any News agent will likely carry it (or other place that has school supplies)...It is a big item (at least in Roseville, NSW) for the primary school teachers who insist that all workbooks and similar are covere in it!

I developed quite a skill in covering things in it.

Cheers,

[erick]

Image doesn't capture it all, but you can see a wrap around the barrel of this Cheshire. Yes, I know, flowers - I pinched a piece from my wife who had been doing the insides of the kitchen drawers!

[bmitchell82]

eric, im getting worried about IIS's, more and more floral decor is showing up, First Steve (kinetic) with his floral scooter mount, now you with your Floral contact. lord don't let me tred this path! hehehe

[Stu Ward]

Thanks for the contact tip guys, worked a treat and is now rock steady.

Got my Collimation all sorted, but now its cloudy and raining !!!!:rolleyes:

[erick]

Perhaps a few of these on the primary? :D

[erick]

Onya Stu! Easy solution.

[bmitchell82]

good lord eric. i think its nearly driving me to change my avatar! :S

[Vanda]

I hope you dont change your avatar Brendan! Its one of my "constants" in IIS. You contribute heaps of knowledge to the forums. As a bonus you have that "mad young scientist" look which matches well with your engineering and astronomical skills!!
My avatar is our Jack Russell Bonnie Boo - thats what I wake up to if I doze off on the couch! You can see what she's thinking - "slacking off again bub - how about a game?"

[bmitchell82]

damn, i have become a knowledge bearing piece of furniture... daym! now im definately going to have to change the avatar.... don't worry itll have the same mad scientist flava! hehehe

[GraemeT]

There was a post some time ago about some self adhesive stuff that looked like carbon fibre from Supercheap Auto. I can't find the thread again, perhaps someone can recall the name of it? It had a metallic base, I think.
Cheers
Graeme

[erick]

That was me again :ashamed:

http://www.iceinspace.com.au/forum/showthread.php?p=595704

I have just updated the thread with one more post and photos of the result.

I should really replace my contact with the Trimbrite stuff. But I don't really need to. I now use Antares Twist lock adapters:-

http://www.iceinspace.com.au/forum/showthread.php?t=50200

They pull up nice and tight on any 1/25" barrel and centre it well.