Orthoscopics?

[John]

The Pentax XO's are not abbe orthos though are they ?. They are a multi-element design differing between the 5mm and the 2.5mm. They are orthoscopic though, which is an optical characteristic rather than an optical design.

There is one for sale in the USA at around $400 I think (used) and thats it.

 

 

[Dave In Vermont]

No one had heard of TeleVue or Plossl's to speak of when I started aquiring gear - 1972. But Orthoscopic was the top-of-the-line that people aspired to get. Today we may be spoiled with 70° & 80° eyepieces everywhere, but Ortho's still have wonderful views to offer if you can handle the short FOV's they provide.

Today I have 3 - 6mm, 9mm, and 12mm. I'm happy! For now.....

Dave

[glynnlondon]

I have all orthos in my kit ( the maxvision aside) they are excellent on doubles and planetary favourite being the hutech 12.5 and 7. Baaders aren't to shabby either the 18 is especially nice.

In my limited experience they are great value for the money, if you can handle the tight eye relief of course.

[Mak the Night]

6 hours ago, John said:

The Pentax XO's are not abbe orthos though are they ?. They are a multi-element design differing between the 5mm and the 2.5mm. They are orthoscopic though, which is an optical characteristic rather than an optical design.

There is one for sale in the USA at around $400 I think (used) and thats it.

 

 

That's a quite interesting point John, which I hadn't really considered before. 

‘orthoscopic’ 

Definitions:  adjective

of, relating to, or produced by normal vision

yielding an undistorted image

~ Collins Online 

Many manufacturers advertise eyepieces as 'orthoscopic' which could just mean that they produce undistorted images. Whether they are the same as the traditional design by Ernst Abbe isn't always clear.

[Mak the Night]

3 hours ago, glynnlondon said:

I have all orthos in my kit ( the maxvision aside) they are excellent on doubles and planetary favourite being the hutech 12.5 and 7. Baaders aren't to shabby either the 18 is especially nice.

In my limited experience they are great value for the money, if you can handle the tight eye relief of course.

I am very impressed with my ortho's so far, particularly the 12.5mm Hutechs, they rival my TeleVue 15mm Plossl pair for image quality and more than compensate for the fact that TV don't make a 13mm Plossl anymore. The Baaders do look nice.

[Mak the Night]

3 hours ago, Dave In Vermont said:

No one had heard of TeleVue or Plossl's to speak of when I started aquiring gear - 1972. But Orthoscopic was the top-of-the-line that people aspired to get. Today we may be spoiled with 70° & 80° eyepieces everywhere, but Ortho's still have wonderful views to offer if you can handle the short FOV's they provide.

Today I have 3 - 6mm, 9mm, and 12mm. I'm happy! For now.....

Dave

I believe it wasn't until the 1980's that TeleVue made the Plossl fashionable. I'm still puzzled as to why there's a gap between the 11mm and 15mm Plossls in the TV range. I find a Plossl of around 13mm to be very useful for my 4" Mak. The 12.5mm Hutech's I've recently acquired give me a 208x magnification for a 0.5mm exit pupil. Which is just about the Mak's limit before I start to see floaters or my own eyelashes or something. lol

[John]

I think the 1st TV plossls were launched in 1979. I bought my 1st astronomy magazine in 1981 and it has a very small advert in the classifieds section for the Tele Vue plossls. I thought it was a rather naff name for a brand, they won't catch on .....

 

 

[Mak the Night]

49 minutes ago, John said:

I think the 1st TV plossls were launched in 1979. I bought my 1st astronomy magazine in 1981 and it has a very small advert in the classifieds section for the Tele Vue plossls. I thought it was a rather naff name for a brand, they won't catch on .....

 

 

Yeah, 'TeleVue' looks like some bad 1950's advertising campaign name or something out of The Jetsons lol. I think Al Nagler started a company in the '70s making devices that would magnify television cathode ray tube screen displays. So you could turn your 22" colour screen into a home cinema or something. I don't think they caught on.

[John]

54 minutes ago, Mak the Night said:

Yeah, 'TeleVue' looks like some bad 1950's advertising campaign name or something out of The Jetsons lol. I think Al Nagler started a company in the '70s making devices that would magnify television cathode ray tube screen displays. So you could turn your 22" colour screen into a home cinema or something. I don't think they caught on.

I always liked this cartoon of Al Nagler

 

[Mak the Night]

3 minutes ago, John said:

I always liked this cartoon of Al Nagler

 

ROTFLMAO!

[paul mc c]

I would'nt be with out a few orthos,probably the pick of mine is the U.O 7mm second right on the top row,unbelieveably sharp on planets although to much power in the 12" sct,but one day i might get excellent seeing and who knows

[Mak the Night]

14 minutes ago, paul mc c said:

I would'nt be with out a few orthos,probably the pick of mine is the U.O 7mm second right on the top row,unbelieveably sharp on planets although to much power in the 12" sct,but one day i might get excellent seeing and who knows

Nice selection.

[John]

I've had a few (plus the TMB SM which is a monocentric of course) but, looking at the dates, I've not actually owned any for 5 years, rather surprisingly:

 

[glynnlondon]

Loving those volcano tops John and good to see Mr. Nagler trying to save his frac back.

I recommend a good quality drummers stool

[Mak the Night]

14 minutes ago, John said:

I've had a few (plus the TMB SM which is a monocentric of course) but, looking at the dates, I've not actually owned any for 5 years, rather surprisingly:

 

They all look good, if they were mine I'd doubt I could part with them. 

[John]

1 minute ago, Mak the Night said:

They all look good, if they were mine I'd doubt I could part with them. 

The TMB 5mm Supermono was the best performer and the best performing low glass eyepiece I've ever owned or used I think. The FoV (~30 degrees) and the tiny eye lens just made it a chore to use though

 

[Mak the Night]

5 minutes ago, John said:

The TMB 5mm Supermono was the best performer and the best performing low glass eyepiece I've ever owned or used I think. The FoV (~30 degrees) and the tiny eye lens just made it a chore to use though

 

Yeah, it does look hard work. Too short a focal length for my Mak though, I've calculated that the smallest f/l EP to get a 0.5mm exit pupil would be 6.35mm (208x). Which interestingly, I can get more or less exactly with my 12.5mm AH ortho's combined with a 2x Barlow.

[John]

Thats an advantage with long focal length scopes - you don't need ridiculously short FL eyepieces to get high powers

[Mak the Night]

The downside is that with my Mak to get a 3mm exit pupil I would need a 38.1mm f/l EP (I have a 40mm Plossl) for a magnification of 34x. A 4mm exit pupil would need a 50.8mm f/l for 26x and to reach a 5mm exit pupil it would take a 63.5mm eyepiece for only 20x! If my maths is right, of course, which is unlikely lol.

[astroavani]

I like all planetary astrophotographer worth its salt have a complete set of orthos and do not give up. Including two 18mm, two 25mm and two Ploss Tele Vue 32 for use with BinoVue. Nagler and I think if we take the orthos the field do not lose anything in the quality, to the contrary, I find them much better for planetary observation due to the lower field that makes us focus spots on the planet.

[Mak the Night]

10 minutes ago, astroavani said:

I like all planetary astrophotographer worth its salt have a complete set of orthos and do not give up. Including two 18mm, two 25mm and two Ploss Tele Vue 32 for use with BinoVue. Nagler and I think if we take the orthos the field do not lose anything in the quality, to the contrary, I find them much better for planetary observation due to the lower field that makes us focus spots on the planet.

Yes, I agree. I was initially concerned about the FOV of the ortho's being only 42°, yet I discovered that it was quite tolerable and helped with concentrating on some lunar features.

[nightfisher]

I still own the full set of circle T orthoscopics and nothing will make me part with them, even though i never use the 4mm way too much fr my long focal length scopes)

[Mak the Night]

4 hours ago, nightfisher said:

I still own the full set of circle T orthoscopics and nothing will make me part with them, even though i never use the 4mm way too much fr my long focal length scopes)

Well, you never know when you will need them in the future lol. There are many things I've regretted selling. Maybe it's my OCD, but having the full set of a collection of eyepieces is particularly satisfying. 

[John]

I expect that Al Nagler is fed up of being asked if / when Tele Vue are going to produce an abbe ortho type eyepiece range.

[jetstream]

Nagler and his team have come up with an almost unbeatable Hyperwide set of eyepieces and I hope they continue their development, sorry to stray off topic.