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The various eyepieces have a focal length, the shorter the number, the greater the power or magnification that you get. So a 20mm eyepiece will show objects larger than the 32mm.
To calculate the power divide the focal length of the scope (650mm I think) by the focal length of the eyepiece, so the 32 mm give 650/32= 20x or for the 20 we get 650/20=32.5x
Beware that high power is nor always better and for these types of scope they really struggle at powers much above 100x unless the seeing is very very good.
The Barlow is used to increase the power. If it is a 2x barlow is doubles the power, so using the barlow and the 20mm will give you 65x.
As regards the upside down images, I believe these scopes are set up with elements in the focuser that create an erect image. Normal Newtonions always show images ipside down and reversed. Which eps are giving you upside down images?
Malcolm
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