C11 Flattener

[MarkS]

I've finally taken the plunge and ordered one of these:
http://www.teleskop-express.de/shop/product_info.php/language/en/info/p3291_Image-Corrector---0-8x-Focal-Reducer-for-Schmidt-Cassegrains.html
Have a look at the spot diagrams at the bottom of the page - very impressive.

Since F8 is a bit slow, I'll be using my Peltier cooled Canon on it - neither the C11 nor the cooled Canon have seen action for a long while!

Mark

[Edit - URL replaced with English language version]

[RobertM]

Will be doing the same when I've sorted out an OAG.  Am also wondering whether it would work with the AP 0.67 reducer which would bring it down to f/5.4 and a quite useful 1500mm f/l.

[The Thing]

Could you not combine the C11 corrector reducer 0.8 thingy with the AP 0.67 if it's just a reducer?

[MarkS]

An interesting idea Robert - it's worth a try ...

Mark

[MarkS]

I hope to do a first test of the flattener tonight.

[MarkS]

Hmm ....  problems!

My existing Canon T-ring did not properly thread onto the T2 extension ring I bought from TS but I thought they were both M42 x 0.75

Maybe I'm wrong.  Does anyone know for sure?

Mark

[Rocket Pooch]

Mark,

M42 and T have different pitches, you probably managed to start getting it on and then it stopped after 3/5 a turn.

Chris

[RobertM]

Had the same problem on Friday. 

I think there are only two flavours of T-threads

M42 Lens mount (Pentax/Zeiss) - M42 x 1mm
T2 lens mount for cameras - M42 x 0.75

The SXV-H9 and, I think most other cameras, have M42 x 1mm whereas most everything else astro uses M42 x 0.75mm.  I think you mist have one of each...

Robert

[Rocket Pooch]

There is only one T-Thread the other is M42.

[mickw]

Does the M42 part connect to the camera as the T bayonet does or does it connect to a lens ?

I'm thinking the bayonet part of the T is a separate component of the adapter and could possibly swapped out ?

[Rocket Pooch]

Hi Mark,

Reading about the flattener it has an M48 on the back, this will need to go down to a T, this is the baby, http://www.teleskop-express.de/shop/product_info.php/info/p3504_TS-Adaptor-from-M48--2--filter-thread--to-T2---low-profile.html

then you will need extension tubes for the right spacing for the reduction.

On my CCD67 similar thing on the back, what I had was a M48 40mm extension this then goes onto the new OAG and then onto the QSI the back focus on the CCD67 is 105mm so, 40mm+5mm (adaptor) + 27mm OAG + 36mm Camera is about right at 108mm.  But what a palava!

Chris

[MarkS]

Reading about the flattener it has an M48 on the back, this will need to go down to a T, this is the baby, http://www.teleskop-express.de/shop/product_info.php/info/p3504_TS-Adaptor-from-M48--2--filter-thread--to-T2---low-profile.html

then you will need extension tubes for the right spacing for the reduction.

That's exactly what I bought - I then also bought a variable extension for fine adjustment:
http://www.teleskop-express.de/shop/product_info.php/info/p2641_TS-Optics---variable-T2-extension-20-5mm-to-30mm.html

BUT my existing Canon T ring will not fit on the back of the T2 variable extension.  And my existing T extension tubes will not fit on the back either.  However the T2 variable extension WILL fit on my existing T extension tubes.  Both my existing T and the new T2 have a thread pitch of 0.75mm - however, it seems that the new T2 bits have a very very slightly larger diameter.

BTW, None of my existing bits (T ring and T extension tubes) fit on the back of the M48 to T2 adaptor, either.

All a bit annoying!

Mark

[mickw]

It may be that no clearance allowance has been made for the anodising.

If sending the lot back is not an option, a fine wire brush (like a suede brush) through the threads may do the trick.

[Rocket Pooch]

That's odd Mark, sounds like its not made properly?

[MarkS]

It may be that no clearance allowance has been made for the anodising.

OK - I've got this working now.  The threads on the new T2 components do look slightly over anodised and I think the first time I tried to screw on a Baader extension tube, it may have cross-threaded.

I've now managed to very carefully screw on a different T ring  - this has now cleaned the thread sufficiently for all my different bits and pieces to work.

Mark