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A word of warning
I gave the 7mm a bit of workout tonight at my favourite semi dark sky haunt.
My intention for this eyepiece was for high power dso viewing and it performs quite well for this. 47Tuc was awesome, as was the closeup view of the ring nebula.
With the uhc filter viewing the saturn neb I could see the faint whispy wings in averted vision which gives it its name.
Regarding edge correction, I detected a small amount of star bloat (field curvature?) away from centre (f5 scope). Its certainly much less than I get from the 14mm XL so its not a deal killer for me. I didnt detect any astigmatism (seagulling).
Now for the bad bit. If you use Baader or Celestron filters you might strike a bit of trouble. THe Baader OIII filter doesnt have a very long threaded section and it seems that the TMB/Burgess might have a taper to the thread start at the end of the barrel.
The upshot is that i couldnt get the OIII filter to hang on which for me was something of a dissapointment. However my Lumicon UHC with its longer threaded section hung on fine.
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