254mm blue tube sw + sw coma corrector. Possible?

[alacant]

Hi

I've a blue 10" sw. I can reach focus through the camera by unscrewing the 1.25 eyepiece adapter and screwing t2 camera adapter direct to the male t2 threads which are then exposed. That then needs 10mm of outward focus.

The sw coma corrector is in effect a 2" nosepiece with male t2 camera mounting threads. Is there an adapter that would enable me to get to focus with the coma corrector and camera?

Cheers

 

[andyboy1970]

I had to modify the 2 inch eyepiece adapter by cutting it down to the top of the flange that prevents it being pushed into the drawtube.

I have a blue tube 200p.

Should have said the CC is the same as a 2 inch eyepiece and can take 2 inch filters on the front so not T2.

[Tinker1947]

Getting the Primary Mirror further up the tube without resorting to drilling holes can be acheive ( i think) by increasing the length of the Collimating screws and replacing the springs with a longer type to keep the mirror from flopping about.....I haven't had a need to test this idea though..

[steppenwolf]

I have the same telescope and I got a machine shop to turn up an adaptor that places the coma corrector deep inside the focus tube.

Have a look towards the end of my website page here.

[alacant]

26 minutes ago, andyboy1970 said:

I had to modify the 2 inch eyepiece adapter by cutting it down to the top of the flange that prevents it being pushed into the drawtube.

Ok, I see that that would work. This is what I have:

I cut below the words '2" Eyepiece Adapter", just above the flange. And the to hold the coma corrector? Friction fit wth tape maybe? Would that be enough to hold a dslr?

[Scott]

Different scope, but I changed the collimation bolts and springs on my 200p and now the primary is approx. 1" further up the tube.  Many ways to skin a cat

 

 

[andyboy1970]

24 minutes ago, alacant said:

Ok, I see that that would work. This is what I have:

I cut below the words '2" Eyepiece Adapter", just above the flange. And the to hold the coma corrector? Friction fit wth tape maybe? Would that be enough to hold a dslr?

Thats what I did so it looks more like the middle one in your picture.

I used RTV sealant to secure the CC in place. That allows me to remove the CC with a little effort if I need to in the future.

[astromerlin]

24 minutes ago, alacant said:

Ok, I see that that would work. This is what I have:

I cut below the words '2" Eyepiece Adapter", just above the flange. And the to hold the coma corrector? Friction fit wth tape maybe? Would that be enough to hold a dslr?

 

I wouldn't use tape or friction fit it won't hold and the dslr will end up on the floor.

Get someone to drill and tap M4 holes in the V groove each at 120 degrees and fit M4x4 grub screws.

 

[andyboy1970]

You could drill through the adapter so that the securing grub screw go all the way through to the CC.

[alacant]

Hi again. It looks as if it comes with 2 adapters:

http://www.tecnospica.es/tienda/es/reductores-correctores-y-aplanadores/2697-skywatcher-corrector-de-coma-para-newton.html

The shorter of the two looks promising. Did anyone else get the same adapters? To work?

On another note, it looks as though I've about 7 clockwise turns on the mirror cell screws. They're the knurled ones, yes? If not the above adapter, then maybe a combination  of the cut off 2" eyepiece adapter, a few turns of the mirror cell screws and some glue? I dare not mess with taking the mirror end apart.

Cutting the adapter anyone? Hacksaw?

Cheers

 

[andyboy1970]

Hacksaw.

God only knows what the two adapters are for that come with the CC.

[alacant]

The smaller adapter has male threads which screw into the female on the focusser. It looks like it's an attempt at the minimum distabce you can have for a 2" accessory such as th cc. Very much me TOL but this would seem to confirm:

 

[andyboy1970]

Doesn't fit the older blue tube scopes with original focuser.

 

[alacant]

Hacksaw it is then!

 

[Mr Spock]

I had a 250 blue tube and Baader MPCC. The MPCC stop ring comes off to reveal a M48mm external thread to which you can fit extension tubes. The MPCC then goes deeper into the focusser.