4mm High Performance Planetary Eyepiece

[N1]

Must have short eye relief, fixed focal length and no more than 45° AFOV and 4 elements.

Needs to be better than the 4mm Fuji Ortho I have and the 3.5 T6 Nagler I had.

Not easy to find so thanks for looking

[Merlin66]

Hmmm
Rather than chase a 4mm eyepiece, why not consider a "good" Barlow and a safer 8 to 10mm eyepiece???

[N1]

Hi Ken, trying to minimise glass, weight, bulk etc. for the grab and go setup while making no compromises on image quality. There is a non tangible aspect to this, and I'm aware of it.

What do you mean by "safer"?

I am planning to get a decent barlow/extender for the imaging side of things later so will be able to compare at some point.

[Merlin66]

A good Barlow/ Powermate has no impact on the visual quality...
In my experience it's easier to find good quality performing eyepieces above the 6mm range. Many to chose from.
(What scope are you using?)

[N1]

Ah, ok, yes definitely easier to find good longer FL EPs.
Currently FS60/FC76 combo for the g'n'g setup. The 4mm OR is pretty darn good so it's not a desperate case ;) Improving on that won't be cheap I'm afraid. All barlows I've been able to try in that setup (combined with good ORs and PLs) have been unacceptably bad compared to the EPs that usually get used in it for "high" power, but then none was a TV (or ES, which I hear are of decent quality).

[Merlin66]

Yeah,
finding suitable (read=quality) visual Barlows can be difficult.
With the Genesis f5 I kept looking for the "Holy Grail" and tried MANY Barlows.
In the end the TMB x 1.8 came out the absolute winner. I also enjoyed the Klee Barlows (x2.2 and x2.8) before settling on the TV Powermates both for visual (x2 and x2.5) and for the solar imaging.
I've just picked up a Baader x 2.25 Hyperion Barlow to try that.....

[Allan]

I can only think of five eyepieces that meet your criteria.

AP SPL, I mention this one first because they are out of production and you will never find a used one at 4mm, so they can be ignored.

TMB SMC, again hard to find, but I managed to assemble a few. Only 30 degree AFOV though, and they only perform well in long focal ratio scopes.

Takahashi Abbe Ortho, available new and the obvious value choice.

ZAO I and II, the best 4mm planetary eyepieces ever made. You don't indicate a price guide, but I might consider selling my 4mm ZAO II for $1100, as I don't have much use for it.

[N1]

Ok had a think about this...ZAO II beyond budget but would consider ZAO I or TMB SMC, possibly a Pentax XP 3.8