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Focusing a Lunt LS35T


Mikey0368

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I'm trying to image with an LS35T that I have on loan but I'm not quite getting there. The camera I'm using is a ZWO ASI224MC, although I have an ASI294MC I could try as well if that would be worth it.

The draw tube is in as far as it will go and it feels like it just need to go in a little bit further to get to focus. Is there anyone here with experience of that scope?

Here's what I got this morning......

Sun_115743_lapl5_ap5190-1a.jpg

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I don't have one myself. Does saguaro's suggestion on cloudynights for the Lunt 50 work?:

Quote

Try this: unscrew the eyepiece holder from the blocking filter diagonal to expose the male T threads on the diagonal. Screw a 5mm or 10mm T thread spacer into the camera and then screw that onto the T threads. This should give you the extra in-distance you need to achieve focus. 

https://www.cloudynights.com/topic/681443-cant-focus-my-lunt-ls50-using-zwo-asi178/

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Edited by Luke
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  • 1 year later...

Did you ever get this working? I recently acquired an ls35t . Visual is great, but I can't get either my asi120mc or a 1.25" webcam to focus. Tried the Barlow lens trick and still no joy.

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 Just for clarity:
 
Where the focuser can't move any further inwards then you have to remove something from the image train.
Not the solar diagonal with blocking filter!

A Barlow or GPC may help by pushing the image outwards enough to reach the camera sensor.
Sometime an all threaded spacer can replace an existing extension. Or a component with a physical length.
By connecting components without adding optical path length.

The ZWO cameras have internal threads to allow them to be joined directly to an instrument or component.
Without using a normal eyepiece receptacle/clamp or nosepiece.

Conversely: When the focuser is fully out and still won't provide sharp focus then you have to add a spacer to the image train.
A Barlow or GPC will NOT help. Only make matters much worse.

My Lunt 60MT needs an extension to reach outward focus with a ZWO '174 camera. Visually it is fine.
The focuser is at full stretch outwards and still not reaching outward focus without additions.
So, yet again, there is no coincidence of eyepiece and camera focus.
 

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