Jump to content
  • Join the online East Midlands astronomy club today!

    With active forums, two dark sites and a knowledgeable membership, East Midlands Stargazers has something for everyone.

2" Eyepieces with f6.3 Focal Reducer?


Recommended Posts

Hi Guys

I have recently acquired a Celestron f6.3 focal reducer/flattener.

I am sure that I have seen somewhere that you do not get the full benefit if you use 2" eyepieces.

Would welcome your comments as to the pros and cons of this.

I have many 1.25" eyepieces but just the one 2" which is the Panaview 32mm.



Link to comment
Share on other sites

There will be no advantage using the reducer with 2" eps. The reducer will cause vignetting, losing some of the light cone since the clear aperture of the reducer is smaller than the field stop on some 2" eps.

You may appear to get a slightly wider FOV, but the view is likely to be substantially dimmer and show up more aberrations.

I notice also that you don't really have a scope which lends itself to a reducer well. The Reducer are made to fit to an sct visual back.

The Sky max 150 has an opening suitable only for 1.25" eps.

If you could get it to fit then it should provide a wider field using 1.25" eps without vignetting.

Link to comment
Share on other sites

The reducer will fit the 8" SCT visual back and will nicely widen the views with your 1.25" eps.

The 2" eps will suffer some vignetting due to both the baffle tube on the 8" being only 1.5" diameter and the configuration with the reducer.

I used to have a Meade 10" LX200 SCT, and once tried my 31mm Nagler with the Meade F6.3 focal reducer. Despite the fact the 10" has a full 2" baffle tube, the views were not nice to look at.

Without the reducer and using a full 2" opening with a Peterson Eyeopener the views were fantastic.

Try it and see, but I think the reducer will not enhance the views with 2" eps as you are already pushing the limits using them with a 1.5" baffle tube.

Link to comment
Share on other sites

Guest Tweedledum

hi Graham,


Can echo Pete's comments above with the Peterson eye opener. It is well worth having to get the full 2" apperture. Likewise had 10" Lx200. The focal reducer will also challenge your eyepieces more, f10 is far more forgiving.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.