What kit for Canon 550D on a Skywatcher 250PX

[Grunthos]

I've just bought a new dobo, a Skywatcher 250PX.

Appreciate that it's not perfect for astrophotography but I;d like to have a stab at connecting up my Canon 550D to the dobo to shoot the likes of the moon etc.

I have an existing T adaptor for the Canon which I've successfully used on my Celestron 6SE.

Can't seem to find a way of connecting it to the Crayford focuser on the 250PX (Dual fit 1.25"/2" focuser that comes with the scope).

What am I doing wrong?

Do I need a different T-adapter for the Skywatcher and makybe an extension tube?

Please tell me I don't need a new focuser or expensive adaptations...

[Stephen]

You shouldn't need anything extra. (A picture of the focuser would really help here.)

Can you unscrew the 1.25" barrel to reveal a t-thread?

[Grunthos]

Sorted.

What I hadn't appreciated was that the 1.25" part of the focuser is in two parts which screw apart.

(Didn't appreciate that in the semi dark last night with cold fingers and a fading torch!)

Have now unscewed them and the DSLR fits fine.

Many thanks Kh3ldar.

[spaceboy]

It will be interesting to hear if you can get the DSLR to come to focus ??

[Tinker1947]

FLO do a 2" adapter that screws in to the T-Mount, if you haven't brought a T-Mount there's this all in one bit of kit..

First Light Optics - Max DSLR Camera Adaptor

[Tinker1947]

It will be interesting to hear if you can get the DSLR to come to focus ??

I have a 10" reflector and use a Nikon with a T-mount and 2" adapter, the focuser is about a 1/4" out of the focusing unit when focused..

[Grunthos]

It will be interesting to hear if you can get the DSLR to come to focus ??

I thought "plug and play" (or should that be screw and view?) was too good to be true!

I'll keep you posted...

PS I'm considering buying these extensions. Would that make any difference if there is an issue with focussing?

[Tinker1947]

I have never used extension tubes, never had the need....

[Stephen]

I thought "plug and play" (or should that be screw and view?) was too good to be true!

I'll keep you posted...

PS I'm considering buying these extensions. Would that make any difference if there is an issue with focussing?

Some times it works, some times it doesn't

You won't want extensions. The typical problem with focusing a DSLR on a newt comes from not enough inwards focus.

[Grunthos]

The typical problem with focusing a DSLR on a newt comes from not enough inwards focus.

Which brings us nicely back to my original post - "Please tell me I don't need a new focuser or expensive adaptations" (e.g Low Profile Crayford Focuser?)

Guess I'll just have to suck it and see next time I break out the glass (hee hee).

[Stephen]

Which brings us nicely back to my original post - "Please tell me I don't need a new focuser or expensive adaptations" (e.g Low Profile Crayford Focuser?)

Guess I'll just have to suck it and see next time I break out the glass (hee hee).

and as I said, some work, some don't

It tends to depend a lot on age of scope - you've got the kit already and you now have found the t-thread. Give it a go and let us know

[RikM]

I am very interested to hear if it works as well. The 250PDS has a different focuser to the 250PX. The PDS also has a shorter tube to give more back focus depth especially for AP.

[spaceboy]

Hang on... you have a flex tube. At a complete guess ??? I would say if you do have any inward focusing problems could you just not extend the scope fully ? If you measure and mark each extension tube so that the length is equal, collimate and then see if you can get focus. You probably will achieve focus with your scope with out the 2" adapter in but just on the off chance you can't this may be a way around it ??? Never having used a flex dob others may be able to better advise.

[Grunthos]

Give it a go and let us know

OK, had a very quick dash outside to check things out.

Initial test suggets the my 250PX (Flex tube Sybscan GOTO) seems to be able to focus (on Jupiter anyway) with a Canon 550D (using a Canon EOS T mount).

Was able to move throught the focus sweet spot no problem.

I can now die a happy man

[spaceboy]

Glad to hear all went OK but you may find a webcam gives better results on planets than DSLR's.