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Further RC ramblings


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I put the RC on the mount last night and after a lot of fiddling I found the focus point.

Not liking the need for  2 extensions, full travel of the focuser and a bit more , then I remebered I had the reducer fitted in there last year so another night of fiddling required.

I did mutter something about shaving mirrors 😎

 

large.20210216_232619.jpg.a0db1516efda13f227409699d1c3791c.jpg

Edited by Ibbo
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It took me a bit of time for me to comprehend what that photo is showing but it certainly seems like their's plenty of opportunity for bending moments to come into play there!  I assume their is a reason why the focal plane set so far behind the rear of the scope?

Edited by Clive
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38 minutes ago, Clive said:

It took me a bit of time for me to comprehend what that photo is showing but it certainly seems like their's plenty of opportunity for bending moments to come into play there!  I assume their is a reason why the focal plane set so far behind the rear of the scope?

I have no idea seems a bit OTT to me.

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If you can move the mirrors further apart on the colli springs it might help.

For every 1 mm distance increased between the mirrors the focal point distance will shrink by about 25 - 30 mm.

Mind you still have to bear in mind the critical distance between the mirrors.

Its all good fun eh 😁 

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Out of interest how far out is the focal plane without a reducer ?

Say if you wanted to use it visually or take a prime focus DSLR exposure.

 

With the focal plane that far back, you'd think you'd put a Powermate into it ?

 

I thought with this fixed mirror optical design the focal length was consistant (ie unlike say an SCT with a moving primary)

 

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3 hours ago, Bino-viewer said:

Out of interest how far out is the focal plane without a reducer ?

Say if you wanted to use it visually or take a prime focus DSLR exposure.

 

With the focal plane that far back, you'd think you'd put a Powermate into it ?

 

I thought with this fixed mirror optical design the focal length was consistant (ie unlike say an SCT with a moving primary)

 

 

The focal point on my RC is 250mm from the rear of the scope.

This is fixed the only variation needed using the focuser is for different sized camera chips.

 

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Wow......10 inches is a lot of room. 

So what if you wanted to say,  image Mars and wanted to add a 2.5x Powermate ?

Would that be a non starter ?

 

( I do appreciate this is not a planetary imaging scope of course.....)

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Reducer located.

Rain stopped play.

 

 

4 hours ago, Bino-viewer said:

Wow......10 inches is a lot of room. 

So what if you wanted to say,  image Mars and wanted to add a 2.5x Powermate ?

Would that be a non starter ?

 

( I do appreciate this is not a planetary imaging scope of course.....)

 

I did venus with it last year as it was only scope to hand without UV blocking glass in the way.

The C11 did not work very well due to the corrector plate I think or maybe it was just too much FL.

 

UV-IR-IR

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4 hours ago, Bino-viewer said:

Wow......10 inches is a lot of room. 

So what if you wanted to say,  image Mars and wanted to add a 2.5x Powermate ?

Would that be a non starter ?

 

( I do appreciate this is not a planetary imaging scope of course.....)

 

It is not so much once you take off the distance the focuser takes up.

If you need more to say image Mars you have very sturdy extension pieces that screw on between the back of the scope and the focuser.

So Mars through a powermate would be no problem.

 

Edited by Graham
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