High magnification Ortho's, how easy to use?

[michael.h.f.wilkinson]

Exactly. There are many orthoscopic designs out there. The TMB Paragon 40mm I have has "orthoscopic" engraved on the housing. It is almost perfectly distortion free (about 1% angular magnification distortion right at the edge of the 68 deg FOV, much smaller inside)

[carlc]

I hope it's okay to cut and paste this (with a link to the original) but I stumbled across this bit of reporting:

NGC 6745 (triple galaxy system) in Lyra was nearly overhead under NELM 6.9 skies, average seeing and above average transparency. Telescope used - 22" f/4 reflector.

The left image is with the 6mm Ethos and the right image is with the 6mm Zeiss ZAO-II, both giving about 383x. The details seen in the triple galaxy system is evident as the three cores are a bit more distinct, especially in the Zeiss. The two cores in the body are lost in the Ethos. The upside down house asterism shows only six stars in the Ethos and NINE with the Zeiss. We had at least five other observers that confirmed this observation, including at least one beginner. If a beginner can see the difference, than anyone can.

I have to admit that the Zeiss is very expensive and very difficult to find as they are long out of production. So we included a 6mm UO UD orthoscopic in the comparison and we found that it is between the Ethos and the Zeiss in performance, but a bit closer to the Zeiss. So...I strongly recommend either the Baader Genuine Orthoscopics or University Optics HD Orthoscopics (pretty much the same eyepiece) if you want to go this route and save a bundle.

It's from faintfuzzies.com http://www.faintfuzz...ervingAids.html

No mention of eye relief though....and 22" what a scope!

[John]

I hope it's okay to cut and paste this (with a link to the original) but I stumbled across this bit of reporting:

It's from faintfuzzies.com http://www.faintfuzz...ervingAids.html

No mention of eye relief though....and 22" what a scope!

Interesting but just try and buy a ZAO II ! - they cost more than an Ethos on the used market.

[carlc]

True but they praise the UO ortho as well.

[John]

True but they praise the UO ortho as well.

Yes it's a good eyepiece. I owned a 5mm UO HD ortho and a TMB Supermonocentric for a while and compared the two quite extensively, with my 6mm Ethos in the mix for good measure. The TMB Supermono had a very slight edge on the nights of the best viewing conditions (ie: around 10% of the time) but otherwise, for optical performance they were very close indeed. I ended up keeping the Ethos, getting a Pentax XW 5mm and letting the others go as I eventually found the tight eye relief, tiny eye lenses and narrow fields of view of the others a bit to much hard work with my undriven alt-az scopes.

[KaStern_Former_Member]

Hello Stargazers,

I own 25 / 18 / 12,5mm U.O. conical Top Ortos, latest series, and a 9mm Baader Genuine Ortho.

I use them with my 8"f/6 ATM dob plus a 2.2x or 2.8x Klee Barlow or a 3x TV-Barlow, or my 6"f/12 Yolo TCT.

I think they are very good. From what I see they have the same optics in the conical tops as in the U.O. HD Orthos,

wich are the same as the Baader Genuine Orthos. The U.O.HD and Baader Genuine have better coatings compared to the conicals.

I think all these japanese made Orthos are worth the money.

But when I compared a 5mm Pentax XO to a 5mm Kasai Ortho on Planets with a 4" f/8 Apochromat the XO gave better contrast.

But the XO costs 4x the price of the Kasai Ortho. Eye relief of the XO is short, only about 3.5mm.

Cheers, Karsten

Edit:

John wrote it better than me:

"The TMB Supermono had a very slight edge on the nights of the best viewing conditions (ie: around 10% of the time) but other wise, for optical performance they were very close indeed."

That`s it! It took very good seeing conditions to see the advantage.

[carlc]

Yes it's a good eyepiece. I owned a 5mm UO HD ortho and a TMB Supermonocentric for a while and compared the two quite extensively, with my 6mm Ethos in the mix for good measure. The TMB Supermono had a very slight edge on the nights of the best viewing conditions (ie: around 10% of the time) but otherwise, for optical performance they were very close indeed. I ended up keeping the Ethos, getting a Pentax XW 5mm and letting the others go as I eventually found the tight eye relief, tiny eye lenses and narrow fields of view of the others a bit to much hard work with my undriven alt-az scopes.

Can you spell 'corneal abrasion'?

I have yet to try out my 6mm Volcano but I can imagine the FOV will be a pain to keep an object in view.

Hello Stargazers,

I own 25 / 18 / 12,5mm U.O. conical Top Ortos, latest series, and a 9mm Baader Genuine Ortho.

I use them with my 8"f/6 ATM dob plus a 2.2x or 2.8x Klee Barlow or a 3x TV-Barlow, or my 6"f/12 Yolo TCT.

I think they are very good. From what I see they have the same optics in the conical tops as in the U.O. HD Orthos,

wich are the same as the Baader Genuine Orthos. The U.O.HD and Baader Genuine have better coatings compared to the conicals.

I think all these japanese made Orthos are worth the money.

But when I compared a 5mm Pentax XO to a 5mm Kasai Ortho on Planets with a 4" f/8 Apochromat the XO gave better contrast.

But the XO costs 4x the price of the Kasai Ortho. Eye relief of the XO is short, only about 3.5mm.

Cheers, Karsten

Thanks Karsten - good to know.

[Kef9]

Huge credit to Pentax to produce 5 and 6 element eyepieces that rival the Zeiss orthos and TMB Supermonocentrics. They really are too modest about their eyepiece lines I reckon.

Yep, I have the 5mm XO and its a great eyepiece. Funny that I find it really comfortable to use as I get my eyebrow bone (i hope that makes sense) to rest on it. I like to really snuggle in so find it more comfortable than other eyepieces which have longer eye relief.

[barbusg60]

With the newer circle t ones that have the safety cut out in the barrel, are they of the same quality as the earlier smooth barrelled ones?

Cheers,

Rob.

[nightfisher]

With the newer circle t ones that have the safety cut out in the barrel, are they of the same quality as the earlier smooth barrelled ones?

Cheers,

Rob.

they are still the same circle T ortho`s just a little updated, and just as good after all these years, i have just ordered the 25mm from lyra

[Antscope]

I recently tried and failed to buy a supermonocentric (try saying that rapidly whilst drunk) so may try one of the japanese orthos or one of the new baadar ep's