Can't focus with focal reducer

[toyos]

Just bought a 12" lx200gps. A bit overwhelmed by the focal length and tried to use the 6.3 reducer, but couldn't get focus at all, not even close. Is this normal?

[[1ponders]]

No it's not normal. Can you focus on the same object without the FR?

[toyos]

Without the FR, yes I can. Maybe I placed the FR at the wrong place?? :lol: I'm sort of new to SCT.

[[1ponders]]

What are you looking at and how far away is it? I'm assuming you are testing this out on a terrestrial object.

What eyepieces are you using? Are you using a star diagonal in the optical train?

[toyos]

No, I was testing it on DSO's. The ep is 13mm TV Ethos with a 2" diagonal.

I'll try it again later. I don't think there's anything abnormal about the scope.

[Matty P]

Hi Toyos,

How are you connecting the FR to the scope?

[toyos]

I attached it to the diagonal towards the scope.

[Matty P]

Is this how you connected the FR to your SCT? Did you attach the FR to the rear cell of the SCT?

SCT --> FR --> 2" Visual back --> Diagonal --> EP

[[1ponders]]

Try focusing on a Terrestrial object first to check. Once you have it focused remove the FR and then refocus noting the direction you have to turn your focuser and the number of turns. This should be fairly constant. Now when you do DSOs you can focus without the reducer, pop the reducer in and then refocus knowing which way and how many turns you need to make, roughly.

BTW The focal reducer works best and at the correct reduction when the imaging plane (they are meant to be used with cameras) is about 105mm from the inner shoulder of the FR. Check to see what sort of distance you have from FR to eyepiece lens using the Diagonal. Also you may find that you can't use the Ethos effectively with the FR. Try a cheaper eyepiece with a smaller field of view.

[toyos]

sct - visual back - fr - diagonal - ep

[toyos]

Thanks for the advice Paul. I'll try it again as soon as the sky clears up.:windy:

[alan meehan]

hi toyos
i had the sameproblem with my fr on my sct i,am pretty sure as paul has said they only work well on cameras not visual,you could try removing the diagonal and try that .the only way i got mine to focus was to do this and place the fr on the t adapter of the camera bringing the fr closer to focus as i no luck visualy
alan

[Roger Davis]

Hey Toyos,

Your order of assembly should be, as Matt said:

First your Scope
then FOCAL REDUCER
then Visual Back
then accessories.

[marki]

I have a crayford on the back of the scope and mount the focal reducers behind that e.g.

Tube -> crayford -> FR -> Visual back or T adaptor-> diagonal/eyepiece or camera.

I have no problems with either F3.3 or F6.3 FR on LX200.