NGC 3324 RC8 Collimation test

[Andy01]

Clear night, full moon = Testing time!
Still attempting to nail down the collimation of this beasty. I want round stars!

I spent 4 hrs tweaking mirrors and doing star tests using this method (http://www.deepskyinstruments.com/truerc/docs/DSI_Collimation_Procedure_Ver_1.0.p df) -

Best result I've managed to date - there's still a couple of seagulls lurking in one corner but overall it appears to be much, much better than before. :)

Also added another 1mm spacer to the image train in front of the camera which has really helped the coma in the corners.

90 mins Ha (https://www.astrobin.com/full/344168/0/).
Wanted to have a crack at M16 but only got a single sub in before it hid behind the neighbours' tree!

Not perfect, but I'm almost there now! :thumbsup:

As an aside, if someone out there offers a collimating service, TAKE MY MONEY!!! :rofl:

[strongmanmike]

It's a tough gig..people say fast Newts are hard to collimate but RC's are pretty challenging too...you'll get there I am sure :thumbsup:

Full Moon imager...aaand thrill seeker! :P

Mike

[barx1963]

Andy
Anthony (former Bintel manager on Camberwell) runs a telescope repair and servicing operation from his home. He told me he can do RC collimation. His contact is 0411 046802 or anthony@battes.com.au
Cannot attest to the quality of his work, but others I now who had their scopes done at Bintel when he was there told me they were fine.

Malcolm

[Andy01]

Thanks for that Malcolm- I’ve just sent Anthony an email :thumbsup:

[RickS]

Just think how satisfied you'll feel if you struggle through and DIY the collimation, Andy :lol: Data looks good...

[tim.stephens]

I really wish I could be there to help you. I've done this for a few people here in NZ and it is such a difficult thing, even for the experienced. Even worse when you have to describe it in a post or email.

I've collimated successfully the RC8 to the newer truss 12 and 14 inch.

There are plenty of ways to do this but you really need to do daytime collimation first with a cheshire or the TAK scope if you have it, then tweak the primary with a nice bright star centered perfectly on the CCD.

I've tried JUST the night collimation using the DSI technique and CCDI, gone back to check it during the day and it's been way off mechanically.

On the RC8 the daytime collimation has to happen with the primary baffle removed so you can see the full spider and secondary baffle/centre spot, otherwise you are just guessing at the primary and secondary centering. The truss versions are easy because you can easily see and align the focuser with a laser pointing at the secondary centre spot independently of the primary AND you can see the secondary baffles from the cheshire without removing the primary baffle. Brilliant!

I think I mentioned this in another post but another issue is the Primary can become dislodged over time - they have a design flaw in that the primary isn't held snug against the primary baffle but there is a small amount of movement if the retaining ring becomes loose. You get perfect collimation in one part of the sky, slew and then it's gone. Infuriating!

Good luck, let me know if you need any further advice - I'm more than happy to help.

Tim

[Brisbaneskys]

Hi Guy's.

For the people that have been fiddling with the secondary mirror spacing on an 8" RC. :shrug:

This information may be of great value. :thumbsup:

http://astro-foren.de/index.php?thread/11753-neues-gso-8-f-8-rc-ritchey-cr%C3%A9tien-203-1624/&l=2

http://rohr.aiax.de/GSOII_RC_14.jpg

Your :welcome:

[tim.stephens]

Thank you!

[Andy01]

Not sure I have the patience required, but will keep plodding on...



Thanks very much Tim :)



Many thanks :)

[RobC]

Andy I hear mumblings from some of my Astro mates that have RC 8's about throwing them in the WPB. Another friend has an RC12 and gets great images. So there is light at the end of the collimation. Luckily my friend with the RC12 never had to collimate it.

Cheers

Rob

[tim.stephens]

Just to keep you enthusiastic about collimation - these scopes can be fantastic. (One of) the best I've seen thus far is from Chris Gomez:

https://www.astrobin.com/users/cgome004/

Stunning images and great processing. All done with very modest equipment. I don't think he has kids... :-)

If I ever get frustrated with my system, I browse through his astrobin page for inspiration.

[LewisM]

I checked collimation on my VC200L last night with my Tak scope. Without a secondary spot it’s difficult. Only out a hair so I am going to image first then decide if I fiddle.... The VC200L can be even more a nightmare than the RCs but it does hold collimation indefinitely once you nail it.

Glad we both have refractors in case frustration sets in :lol: