Quote:
Originally Posted by Orionrules
Are the eyepiece 2 ins and 17 mm focal?
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A bit of extra information that may be an answer to your question.
(extracted from Agena Astro site (that US supplier mentioned above):
Quote:
The front negative lens element is designed to be removed (and exposes an M48 2" filter thread). This converts each Hyperion into a longer focal length high-quality projection eyepiece, giving the imager two choices of focal length with each eyepiece. NOTE: The 24mm Hyperion is a different optical design and does not contain a removable front element. However, the Front Barrel can still be removed in order to attach 2" filters in-between the 1.25" and 2" barrels. This is particularly convenient for users of 2" filters.
Table 1: Combinations of Hyperion Eyepieces with Finetuning Rings (FTR) to Modify the Focal Length
Effective focal length ...... With 14 mm FTR | With 28 mm FTR | With 14 + 28 mm FTR | Without first group of lenses
Hyperion 3.5.............................. 2.5 ....................2.1 .................1.8 .......................21.8
Hyperion 5.0...............................4 .0 ....................3.2 .................2.6 .......................22.5
Hyperion 8.0...............................6 .0 ....................5.0 .................4.3 .......................21.8
Hyperion 10.0 Coming Soon Coming Soon Coming Soon Coming Soon
Hyperion 13.0..............................1 0.8 ....................9.2 ...............8.1 ........................22.9
Hyperion 17.0..............................1 3.1 ...................10.8 ...............9.2 .........................21.8
Hyperion 21.0..............................1 7.6 ....................15.5 ...............14.0 .........................32.2
Hyperion 24.0............................... N/A N/A N/A N/A
End Quote