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Old 08-09-2015, 08:27 AM
julianh72 (Julian)
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A bit more googling suggests it is technically called a Jones-Bird Newtonian:
https://en.wikipedia.org/wiki/Newton...ope#Jones-Bird

A Jones-Bird Newtonian telescope (sometimes called a Bird-Jones) is a mirror-lens (catadioptric) variation on the traditional design sold in the amateur telescope market. The design uses a spherical primary mirror in place of a parabolic one, with spherical aberrations corrected by sub-aperture corrector lens[20] usually mounted inside the focusser tube or in front of the secondary mirror. This design reduces the size and cost of the telescope with a shorter overall telescope tube length (with the corrector extending the focal length in a "telephoto" type layout) combined with a less costly spherical mirror. Commercially produced versions of this design have been noted to be optically compromised due to the difficulty of producing a correctly shaped sub-aperture corrector in a telescope targeted at the inexpensive end of the telescope market.
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