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jadcx

Focus problem with SX mini-wheel kit

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Hi

I’ve recently got some shiny new kit, and last night was the first clear skies here when I had the opportunity to try it all out.  This is not my first time observing, so I’m well prepared for unexpected issues, but it is my first time ccd imaging.  There was lots of learning, including; cable management needs to be better, I (still) never have the right USB cable, and the focus tube needs some mechanical refining to address slippage.  But the problem I’m not sure how to solve is one of focus.

I bought the SW Trius 814 kit (Trius 814, mini usb filter wheel with OAG, and Lodestar X2) and naively thought that perhaps if it was sold together it would all work together.  And maybe it does, I’m not immune to stupidity :)

I could achieve focus with the 814 relatively easily, and even captured a test image and solved it in Ekos, all very heart warming.  But I couldn’t then get focus with the Lodestar X2 (attached to the integrated OAG in the mini wheel) without pulling the focus tube out considerably further (approx. 50-80mm I didn’t measure).  This obviously isn’t ideal.  Am I missing something?

The setup is:

ED80 -> Field flattener -> filterwheel with OAG ->  Trius 814  with the Lodestar attaches directly to the OAG.

All advice appreciated, and please don’t imagine that I won’t have missed something ‘obvious’ :) 

 

Thanks

 

Justin

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Hi, it all sounds correct to me, thre SX kit is designed to all work together and the lodestar should focus within the range of the movement of the OAG stem...have you got a picture of the SX kit all set up as you had it last night...sometimes a picture can show much more than trying to explain.. :)

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Did you try to adjust the focus on the OAG itself, by sliding the stem up and locking in place... sorry to ask the obvious.. :)

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No, I don’t have a picture but I *thought* I was trying to focus by moving the Lodestar up and down on the prism post.

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1 hour ago, jadcx said:

No, I don’t have a picture but I *thought* I was trying to focus by moving the Lodestar up and down on the prism post.

Yes that is correct, the whole prism assembly slides up and down, with guide camera attached and then there is a lock screw to lock in place.. :) I’m just wondering if it something to do with the field flattener as the focus point will be different..but it would also be different for the camera, so not so sure now.. 

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I have the same kit and it works fine.  You have the 2 adjusters, the bottom (longer) one is to position the prism relative to your filters.  You need this as close as you can to the edge of the filter but clear so it doesn't cast shadows.  You then need to adjust focus by undoing the shorter top screw and sliding the camera only up and down.

If you are having to move it out that far it sounds like you have the post too far out so your prism isn't sitting close enough to the filters.  Below is an image from SX and this is how you need it to look, and it should then focus fine.

miniwheel1a.jpg.83b4c709455d132403547678352be4e4.jpg

 

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Thanks, I’ll have another look and compare the SX image.

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Had some clear skies last night and so finally got outside to look at this again - short version; problem solved, and yes, I feel like an idiot!  I hadn't removed the significantly sized spacer fitted to the front of the Trius.

It was one of those moments where I saw it immediately yesterday and can't for the life of me work how how i didn't see it before :) 

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2 hours ago, jadcx said:

Had some clear skies last night and so finally got outside to look at this again - short version; problem solved, and yes, I feel like an idiot!  I hadn't removed the significantly sized spacer fitted to the front of the Trius.

It was one of those moments where I saw it immediately yesterday and can't for the life of me work how how i didn't see it before :) 

Great stuff, glad you got it sorted.

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On 12/28/2017 at 15:13, RayD said:

Great stuff, glad you got it sorted.

 

On 12/28/2017 at 12:54, jadcx said:

Had some clear skies last night and so finally got outside to look at this again - short version; problem solved, and yes, I feel like an idiot!  I hadn't removed the significantly sized spacer fitted to the front of the Trius.

It was one of those moments where I saw it immediately yesterday and can't for the life of me work how how i didn't see it before :) 

Thank you so much for posting your fix! I just purchased a SXH694 and the Lodestar 2 with the mini filter wheel and couldn’t figure out how to get both in focus! I had the spacer on as well! ?

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On 16/01/2018 at 05:53, Starship3010 said:

 

Thank you so much for posting your fix! I just purchased a SXH694 and the Lodestar 2 with the mini filter wheel and couldn’t figure out how to get both in focus! I had the spacer on as well! ?

I'm fairly sure that my 'solution' falls way short of a fix - just 'doing it properly', but either way, I'm happy it helped.

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