2 inch or 1.25 inch eyepiece?

[mblann1960]

First let me say hi...I'm brand new here and very new to astronomy. Just recently aquired the Celestron Nexstar 130 SLT ( having even used it yet...). I've noticed that this scope will take 2 inch or 1.25 inch eye pieces. Wouldn't it be better to just purchase 2 inch eye pieces? What's the difference? other than the size....I want to get a barlow lens, but am wondering would it be better to get a 2 inch one?

Any help would be great!

I'm really excited about getting into this new hobby!

Mark

[RikM]

Hi Mark, welcome to SGL.

All a 2" eyepiece does is allow to allow a wider field of view but this doesn't necessarily mean that a 2" will always give a wider field of view. It depends on optical design. If you particularly want a super wide field of view at low magnification you will have more options in a 2" fitting. For shorter focal lengths it isn't necessary to use so much glass so these tend to be 1.25". There is no inherent difference in the quality of the view between barrel sizes.

Like many people, I have a single 2" widefield low power eyepiece and then rest of my lenses are 1.25". They all have 68° - 70° apparent field of view. This just means the image circle you see is the same size with each eyepiece, only the magnification changes.

[mblann1960]

Thanks for the info RikM

I guess what got me thinking of this was I saw a 2 inch Barlow lens, and thought...so do I get this? or the 1.25 Barlow? Lots to learn for sure!

Again, Thanks!

[rwilkey]

Hi Mark, and welcome to SGL.  To be honest, I don't think a 2" Barlow will benefit you, the reason I am saying this is because one usually buys a 2" eyepiece for wide, low power views, in other words you wouldn't want to Barlow this as otherwise it defeats the object of using a low power eyepiece in the first place.  I bought the 2" ED Barlow once and never used it, so have just sold it.  Use your money to get a good 1.25" Barlow like the Orion 2x Shorty Plus or something, as you will only use a Barlow with 1.25" eyepieces.