2" and 1.25" eyepieces

hey guys

Im just wondering whwat the difference is, example a televue ethos eyepice comes in either size barrel so what the advantage or disadvantage in 2" or 1.25"???
cheers

anybody!!!!.....

Long Focal length Wider FOV eyepieces have a wider field stop which would be vignetted by a 1.25" barrel. Hence the advent of 2" barrels and focusers with the advent of Widefield long focal length eyepieces with 2" barrels. The reason the Shorter Focal length wide fields which don't strictly need a 2" barrel often have them as well as a 1.25" barrel is so that those with 2 inch focusers who don't like messing around with 2"-1.25" adapters don't have to. (swapping it in and out when the change eyepieces from a shorter to longer Focal length EP or visa versa) The just leave the adapter in the EP case and use all their EP's in 2 inch mode so its a straight swap with no messing about when they change EP's

ah! I see, thank you

Calibos wrote: Long Focal length Wider FOV eyepieces have a wider field stop which would be vignetted by a 1.25" barrel. Hence the advent of 2" barrels and focusers with the advent of Widefield long focal length eyepieces with 2" barrels. The reason the Shorter Focal length wide fields which don't strictly need a 2" barrel often have them as well as a 1.25" barrel is so that those with 2 inch focusers who don't like messing around with 2"-1.25" adapters don't have to. (swapping it in and out when the change eyepieces from a shorter to longer Focal length EP or visa versa) The just leave the adapter in the EP case and use all their EP's in 2 inch mode so its a straight swap with no messing about when they change EP's

Could this be explained in language suitable for a still wet behind the ears newcomer :huh: :ermm: