As the new owner of Steves 7mm TMB/Burgess I gave it a bit of a test tonight in my 130mm f5 newt looking at luna through sucker holes in the clouds.
Comparing it to a 7mm circle-T ortho I noticed that the B/TMB is sharp, just as sharp as the ortho given that the seeing isnt exactly flash tonight.
There was a little more scattered light as one would expect considering the extra elements in the B/TMB.
As a secondary test, I focused on a streetlight(
) in the next street looking for specs of dirt on the lights lens. Its seems to be a good test subject when looking at sharpness and resolution at higher powers. The B/TMB again was every bit as sharp as the ortho
There is one aspect of this eyepiece that gets a thumbsdown from me.
I find it quite hard to hold the exit pupil while standing and looking into the scope. Eye placement seems to be quite sensitive and adjusting the eyecup up and down I could not find a position that helped much.
Steve mentioned that he thought the fov seemed small and cramped and percieved it to be less than 60 degrees. I didn't think so myself, in fact during my attempts to examine sharpness at the edge of field, I would move my eye to look to the side and immediately suffer blackout at the edge of field
In this scope, standing up and viewing the moon, I can only see the entire field if looking near the centre of fov.
Hopefully I will learn how to view through this eyepiece properly and find that it works better in my 10 incher.
It goes to show that peoples eyes are different to others and that eyepieces that work for some, might not work for others.