do i need a 2" diagonal?

I want to get a wide angle eyepiece ( Dave Branigan's Moonfish has given me wide angle fever!)

I can get wide angle pieces for my 1.25" diagonal, but would I be better just getting a 2" diagonal and getting a 2" wide angle eyepiece? Will i get much (or any) more sky into the eyepiece with a 2" over a 1.25?

Hey wide angle fever......sweeping the nation and no known cure :lol:

A 2" eyepiece will usually have a greater apparent field of view then the equivalent 1.25" eyepiece of the same focal length.

Another thing you need to consider is the design of your scope If the eyepiece exceeds the capabilities of your scope to fully illuminate it you will get vinieting towards the edged of the field.

DB

Hi,
High millimeter wide angle eyepieces tend to be 2", low millimeter wide angle eyepeices can be 1.25", so if you want a 26mm wide angle eyepiece it'll probabily be a 2".
Of course this is presuming your scope can take 2" eyepieces. If it cant, then there isnt much you can do with 2" eyepeices.

how do you work out if your scope is suitable for 2" eyepieces? is there a formula to use?

If the opening that accepts the eyepiece is 1.25" wide then a 2" eyepiece barrel isnt going to fit in there, presuming you're not using a 2"-1.25" adapter without knowing it. What scope are you using?

You will need to get a 2" diagonal. i think you have an sct so it will need a diagonal with an sct thread.

But you need to do a bit of research to find out what is the maximum field of view possible for your scope as otherwise you will be spending your hard earned dosh on lenses that will not be fully illuminated.

For example for my 8" SCT with an internal baffell behind the back plate of 1.25" it gives a maximum field of view of about 1.08 degrees so any eyepiece that gives a fov greater then this for me would be a waste of money as the extremities will not be illuminated.

Your 6" scope may be the same deal as mine but unlikely to be greater.

Hope this helps.