Can a Pentax XW 10 mm with a good Barlow perform as well as a Pentax XW 5mm?
Is a the 5mm just a 10mm with a built a built in Barlow?
I have a Televue 2x 1.25" Barlow and a 2x Powermate.
I also already have the 7mm XW, so 10mm with a Barlow/ Powermate would give 5mm and 3.5mm in a tidy package.
Mainly, these would be used with refractors - a 120ED f/7.5 and a 110ED f/7