Hi,
You won't necessrily need all eight I think. Hyperion EPs have a detachable front Barlow element group which then increases the focal length. For instance a 8mm EP becomes a 21.8 mm EP, albeit with a 2" barrel instead of the 1 1/4" which was removed with the front group.
Then you can buy Fine Tuning Rings which fit between the front group with its 1 1/4" barrel, and the main body of the EP with its 2" barrel. These FTRs further modify the focal length and can be bought in 2 sizes, 14 mm and 28 mm. The attachment shows the effect, as these FTRs can be used singly or together. So one lense can be made to have 5 selectable focal lengths. A 13 mm Hyperion can function as that, also 8.1 mm, 9.2 mm, 10.8 mm, and 22.9 mm.
http://www.baader-planetarium.de/sek...verview_en.pdf
The exception to all this is the 24 mm Hyperion which has a different design.
I am about to purchase a pair of these FTRs myself. Reviews seem to indicate they do not degrade the image noticably.
Cheers