Hyperion Hacking?

[Ags]

So, I've got a couple of hyperions, a 17mm and a 24mm.... The 17mm has a removeable Smythe element ang the 24mm has the same removeable piece but no lens.

(If you don't know, a Smythe lens is a combined barlow/field corrector)

(1) What if I swapped the Smythe lens from the 17mm and put it on the 24mm. Would that give me a 21mm EP for free?

(2) The thread on the smythe lens part is a 2" filter thread. For the next hack, screw it into the back of a filter-threaded 2" to 1.25" aadaptor, and use the smythe lens as a mild barlow for all your 1.25" EPs! For more fun you can throw in your fine tuning rings to up the barlowing!

I'll try out experiment (1) next good night... But I don't have a 1.25" to 2" adaptor for experiment (2).

[Ags]

I tried out my hack of putting the 17mm Smythe on the 24mm, and it was not a success. Firstly the apparent field of view was cut down to about 55 degrees and secondly the field did not reach focus uniformly - you could either focus the edges or the middle of the field of view.

Scrap that idea then.

[CGolder]

i would guess the 24mm was already corrected as it doesnt require a lens, so overcorrection with the smythe i thinks

[Ags]

Yes - I didn't realise how much correcting the smythe is doing! I thought it could not be strongly correcting, given that the smythe works at different spacings with the fine tuning rings, and the 17mm is supposed to function as a 2" EP without the smythe.

I thought it might not work, but I was really surprised by how badly it failed.

[John]

Baader take trouble to design these eyepieces with carefully selected and designed matching lens sets to achieve the focal length and as crisp as possible FoV. I guess it's not surprising that "mixing and matching" delivers less than optimal results. But there is no harm in trying, as long as you don't get any dust into the internals

I think Hyperions work at their best as 1.25" format eyepieces.

[Ags]

In a way I'm relieved it didn't work - I would have spent half my time unscrewing my eyepieces and getting in a muddle about which bit belongs where... :-(