I will second Floyd's vote on some poor eyepieces from Russel. The 18mm widefield has virtually no eye relief which was advertised by Russel as having much more. The 19mm is better in this regard but both of these designs suffer in a fast dob.
I've used the 7mm Seibert in my fast dob with success on the planets but I can't comment on the longer focal length models. I also agree with Floyd regarding the dim,poorly performing 7mm type 1 nagler, My Seibert 7mm outperformed it on DSOs!
I've used the 7mm Seibert in my fast dob with success on the planets but I can't comment on the longer focal length models. I also agree with Floyd regarding the dim,poorly performing 7mm type 1 nagler, My Seibert 7mm outperformed it on DSOs!