[koputai (Jason)]

Hi Folks,
I've read in Texereau that the longest eyepiece you should use is f x 7mm, so for my f6 8" that means 42mm. That being said, you can have a 42mm ortho (45 ish degrees) giving a TFOV of around 90 arcseconds, or a Panoptic (41mm) giving TFOV of 140 arcseconds. If the limitation is based on light beams in the scope, is it possible that a wide field 42mm eyepiece would be vigneted or suffer some other catastrophic uselessness?
Seeing as Texereaux was last revised in 1984, is there more modern thinking on what the widest view should be from a Newtonian?

Thanks,
Jason.