I need some serious help collinating a GSO RC

[allan gould]

After Astrofest I did something in a series of silliness and I need some help.
The primary mirror of my 10"GSO RC was filthy and so I decided to clean it. While I was at it I decided to clean the secondary as well.
No problems - two clean mirrors back in the tube.
I thought it would not be a problem re-collimating it but here is where my world imploded and I wound up with a totally messed up scope.
Total miss alignment. Bought a cheshire eyepiece but I just made things worse.
When collimated its a beautiful scope - so how do I get back to both mirrors being collimated and what hardwear/laser equipment would people recommend?
Thanks for any advice.
Allan

[RickS]

Hi Allan,

I used to collimate the one I had with a Tak collimating scope then fine tuned it with star testing and Al's Collimation Aid. Not sure if that's going to be sufficient if your starting point is too far out but you're certainly welcome to borrow the Tak scope...

Cheers,
Rick.

[jwoody]

Gday Allan
You will probably need the Tak collimating scope to get back on track.
I have one if you want to come around (I am in Ormeau) and we can get it sorted.

Jeremy

[allan gould]

Thanks for the offers guys, I've had another attempt with a Cheshire eyepiece and it looks centrally even and it's no longer drastically mis-aligned. Since I have no experience with the Tak collimating scope I might have to take up one of your generous offers. But before I do so I will rig up with my camera and see if I can collimate using the DSI collimating procedure and Al's collimation guide on real stars.
It's gratifying to know there is a plan B if I need it.
Thanks so much for the offers.

[byronpaul]

Allan,

aside from collimation, you need to ensure you get the mirror distances spot on else you'll have major curvature.

No sure of the exact distances of an RC10 as I have an RC8, but others will know. Else PM LucasB as he ripped his RC10 down plenty of times and know's the answer.

You'll want to platesolve an image to verify the result. Here's a link with some info, and there are plenty more online

https://www.cloudynights.com/topic/423163-precise-rc-mirror-spacing/

I have a Tak scope, but prefer to use a Howie Glatter Laser Collimator with Concentric rings.

Good luck.

Paul

[Marke]

Allan for what its worth I can tell you what i do .
First wind the primary all the way back to the stops so it isn't tillted.
Assuming you have a centre spotted secondary and a focuser tilt plate.
I use a barlowed laser and adjust the tilt plate till the beam hits dead centre on the secondary spot , rotating and adjusting till it stays centred .
Then I adjust the secondary til the return beam hits dead centre of the laser , So now you are physically aligned.
Then all you need to do is ONLY adjust the primary at night on a defocued star till its concentric and you should be good to go .

[multiweb]

Sounds like a plan. Can you adjust the primary on these scopes?

[Marke]

Yes Mark thats really the main way to collimate , get it mechanically alligned then collimate with the primary . It has push pull screws on the back.

[multiweb]

Cool - too easy.