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Originally Posted by janoskiss
But wait there's more! I just received an older style tiny little 10.5mm TV Plossl from Chris (33South) and was looking at Saturn with it the other night. I compared it with the 9 & 12mm HD orthos, and the TV seemed to have the best contrast. The moons of Saturn stood out more clearly (esp. one very close to the planet) in the plossl than in either ortho. I'll have to do more testing to confirm this but I might have a new winner for contrast and maybe transmission too.
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Steve,
The difference in magnification and exit pupil between these 3 eyepieces is too great to prove much in terms of light transmission, contrast and sharpness. When comparing eyepieces, particularly as the focal length gets shorter, they need to be the same focal length or at worst within 1mm of each other, particularly when testing on targets on the threshhold of visibility. The reason is that visible limiting magnitude changes as magnification and exit pupil changes. In other words the 10.5mm focal length of the TV plossl could be "the sweet spot" at which those targets are best viewed in your scope.
The differences between these two eyepieces and the 5 element Japanese Manufactured plossls from Celestron, Meade, Parks and Orion in the USA and Antares in Canada is marginal at best. Also include the Tak LE's for that matter, which again are a 5 element plossl. They are all outstanding and so close in performance its not funny. If anything the TV plossls give a slightly warmer tone than the others IMO, which is something you may or may not like.
CS-John B