Help to mod Mak Newt to achieve focus with flip mirror

[dcubed]

HI I have just started using a 200mm Skywatcher Maksutov Newtonian and have had to ditch my trusty flip mirror so can no longer quickly switch form eyepiece viewing to imaging.. 

I am not so keen to get the drill out until I know exactly what I am doing!.  With my old 10 inch ancient scope I move the focuser and spider and it worked fine.  I have a feeling of dread about attempting the same thing on  the new scope as its  still looks prestine. 

Is the simplist mod to raise the primary mirror.  I I need somehere between 5 and 10mm to achieve focus.  I have attached some pcitures!

You can see the 50mm tube extender I am using to achieve focus.  This is just a bit smaller than the flip mirror. 
I am also a little concerned about clearance and obstructing the path to the CCD.  The question is do I just live with this or is it worth butchering the scope to give me back my flip mirror whcih I enjoy!

[Ricochet]

Could you gain the extra in focus with a lower profile focuser? If you got one that fits the same mounting holes there wouldn't be any drilling needed. 

[michael.h.f.wilkinson]

Shortening the distance between the primary and secondary, in order to create the back-focus you need is OK in a regular Newtonian, but in a Mak-Newt you need to maintain the correct distance between the corrector and the primary as well. Raising the primary will not do that (although 5mm might not be a big deal). I wonder if a lower profile focuser wouldn't be the better solution

[Alien 13]

I am wondering if one of these would provide a shorter light path without any major modifications.

https://www.firstlightoptics.com/baader-planetarium/baader-q-turret.html

Alan

[dcubed]

Great suggestions.  I think i might go with a high quality low profile Crayford focuser. 
But might just see if I can bring it in by winding in the primary mirror to see if I can get it in. 

I get the point about not disturbing the secondary / correction plate and the margin I have toplay with wont be big!

I also like the idea of the turret but am unsure if these can be engineered well enought for 2 inch camera loads.

[John]

I didn't know that Skywatcher made a 200mm mak-newtonian. The stock one is 190mm I seem to recall. Is yours a "special" ?

 

 

[dcubed]

i dont think soit just says 200mm on the OTA!

[John]

22 minutes ago, dcubed said:

i dont think soit just says 200mm on the OTA!

Looks like a conventional 200mm F/5 newtonian to me 

[michael8554]

As Michael HFW says the primary to secondary distance is crucial to the coma performance.

But are you imaging out to the edges of the field?

If not 5mm of mirror movement might not impact on the area you're using.

Why not try it, counting the screw turns so you can get back to normal ?

Michael 

[Ricochet]

19 minutes ago, John said:

Looks like a conventional 200mm F/5 newtonian to me 

It does, but there are no secondary spider adjustment thumbscrews and there's a schott glass logo stamped on the side.

[John]

Just now, Ricochet said:

It does, but there are no secondary spider adjustment thumbscrews and there's a schott glass logo stamped on the side.

Yes I noticed that. Confusing isnt' it ?

I guess a photo down the tube would confirm the design 100%.

Maybe a 190mm Mak-newt optical set has been re-housed in a conventional newt tube ?