Hey Ezy
There's not a great deal of difference, to be honest.
They give very similar views.
The E-lux is the eyepiece which Celestron supplies with their 9.25 SCT and has a barrel undercut where the 26mm SkyWatcher Plossl has a straight barrel.
Other than that, very similar. Even in price. I think both sell between $70 and $80.
I'm willing to lower my package deal price, by the way.
All 5 Eps (Skywatcher 6.3mm plossl, 10mm super plossl, GS 15mm plossl, Skywatcher 26mm plossl, Celestron E-lux 25mm plossl) and GSO 2x barlow for $140.
A nice collection for rough and tumble backyard viewing
