Using a barlow/powermate on an LS50

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JochenM
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Using a barlow/powermate on an LS50

Post by JochenM » Mon Jan 06, 2020 12:57 pm

Hi everyone. Happy Monday!

Does anyone here have any experience using a barlow/powermate on a Lunt LS50? In my last two sessions I've been trying to get my Televue Powermate 2.5x to work (in combination with a ZWO ASI 178); but I can't achieve focus (running out of inwards travel on the focuser).

I've tried adding some extension tubes (a total of 30mm between the blocking filter and the barlow) to move the camera further back and the image seems to get marginally closer to focus; but nowhere near enough. Would it be worth trying to add more space (I would need to buy some larger extenders) or am I simply wasting my time because it's not possible to do this with an LS50 (which is fine, very happy with it as a full disk imager)?

Thanks in advance for any insight.

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Re: Using a barlow/powermate on an LS50

Post by krakatoa1883 » Tue Jan 07, 2020 12:39 pm

Yes, it is possible to use a 2.5x Powermate with the Lunt 50 scope, however it will move the focus point very far from the original position. Note that the original focuser of the Lunt provides only a very limited focus range thus using spacers is unavoidable.
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Re: Using a barlow/powermate on an LS50

Post by Merlin66 » Tue Jan 07, 2020 9:34 pm

Can't speak for the Lunt 50, but there's generally no issues using Powermates ....I regularly use the x2.5 PM (with the T thread camera adaptor)
Remember the back focus spacing of the PM doesn't affect the magnification.
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Re: Using a barlow/powermate on an LS50

Post by JochenM » Thu Jan 16, 2020 12:22 pm

Problem solved. Seems I was needlessly overcomplicating things. I'll document it here in case anyone else with the same issue ever ends up in this thread. The solution ended up being as simple as:

1) Unscrew the lens cell from the powermate's extension tube.

2) Get an adapter that gives you a possibility to screw a camera (T2 thread) directly on the lens (I just got the one from Televue themselves as in the image below).

Image

3) Screw the camera directly on top (no additional spacing needed) and enjoy your higher magnification.

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Re: Using a barlow/powermate on an LS50

Post by marktownley » Thu Jan 16, 2020 8:54 pm

Thanks for the info on the fix!
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