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Steve,
2" eyepieces invariably have a much larger eye lens and longer eye relief which makes them a lot easier and more comfortable to use. Kidney beaning and blackout are also rarely an issue with 2" eyepieces. The 27mm Panoptic compared to the 24mm Panoptic is a classic comparison. Only 3mm difference in focal length but the 27mm has a lot more eye relief and is a lot easier to use. The downside is that 2" eyepieces are much larger and heavier so its not a good option for "toy" telescopes.
FWIW Houghy's approach is fine when your visual scope has a long focal length. Houghy uses a 12" LX 200 GPS (not a toy), so medium focal length 2" eyepieces give him high power and the long focal length 2" eyepieces give him low/medium power. His scope has a 3 metre focal length so an eyepiece like the 2" 17mm Nagler T4 gives him 180X. At the low end of the scale, the 41mm TV Panoptic gives 75X with almost a 1 degree TFOV. You then use a 2" barlow with your 2" eyepieces for planetary work. This is also a very good way to go if you own a large DOB with a focal length over 2.5 metres.
Of course its an expensive journey if you head down that road, as EVERYTHING 2" is very expensive (over $400 for an Astronomiks OIII filter for example), but practically and optically it's the right way to go. It doesn't help the guy with a 4" refractor or an 8" dob as the 2" eyepieces are really only suited to low/medium power widefield views, and you need to go a lot shorter in focal length to get high powers.
CS-John B
CS-John B
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