MORE 3 inch eye pieces!!!

[25585]

Masuyama http://www.apm-telescopes.de/en/eyepieces/3-inch-eyepieces/masuyama-3-inch-barrel-eyepiece-80-mm-focal-length.html

3 inch barrel Masuyama 80mm eyepiece

A brand new design that offers long focal length telescope users low magnification, a wide field of view and an immense actual FOV!

In collaboration with Mr. Masuyama of Masuyama eyepiece fame, Kokusai Kohki has gone out on a limb in introducing a truly new eyepiece, the 3 inch barrel size Masuyama 80mm. This eyepiece is aimed specifically at the many private and public owners and users of long focal length telescopes, who would like to greatly reduce the intrinsic high magnification of their telescopes while also significantly widening the FOV they are able to attain at this low magnification, gaining striking celestial views reminiscent of those seen through similar aperture dobsonian telescopes.

What is the advantage of a 3 inch eyepiece?

Although an 80mm focal length eyepiece is hardly unheard of, an 80mm eyepiece of 2 inch aperture imparts a narrow FOV that hardly gets the blood pumping, and the oohs and ahhs coming. In contrast, the 3 inch aperture Masuyama 80 goes far beyond the current 2" (50.8mm) paradigm by boldly going where few eyepieces have gone before, into the parallel universe of 3" barrel width (76mm) eyepiece design. A peculiar new universe that now allows low magnifications AND wide fields of view.

A new design

The Masuyama 80 is not a mere extension of the previous Masuyama design but a brand new design that allows it to perform with excellent image sharpness from center to edge, and little to no light loss at the field edges. Viewing through a C11 at 35X, with over 1.5 degree FOV, this eyepiece sends long f/l telescopes into the realm of Rich Field Telescopes and short f/l Newtonians. With a field stop diameter of 70mm, at a 52 degree apparent FOV, the huge image combined with the amazingly lowered magnification creates a feeling of a much larger area of space being viewed that what the modest number 52 would suggest. After all, how many full moons would fit in a 1.5 degree actual field of view?

Made in Japan

Each hand made Masuyama 80 is carefully and lovingly designed and manufactured at our factory in Tokyo. Each eyepiece is fully tested before shipment and is anointed with its own serial number. Production runs are limited. Each air to glass surface is fully multi-coated. A rubber eye guard insures optimal eye positioning. And a large "tire" placed around the bottom half of the eyepiece, covered in a non-slip rubber rollet, provides a secure hand hold for the hefty 1.7 Kg (3.74 lb) weight of this massive eyepiece.


Is the Masuyama 80 a good fit for shorter focal length telescopes?

The Masuyama 80 is certainly not for everyone, but as long as your telescope is equipped with a 3" focuser sleeve, the Masuyama 80 will provide excellent, distortion free views as well. For example, when attached to a APM 130/F6 CNC-LW telescope, the Masuyama 80 provided surprisingly clear and fresh images at the mere 9X magnification that this combination produces. No edge distortion or vignetting is seen, and images from field center to edge are sharp and contrasty. So yes, the Masuyama will also work well with shorter focal lengths. However the true value of the Masuyama 80 remains with long focal length telescope users who want to gain a wide field, low power window to the universe similar to those provided by the beloved dobsonians.


Delivery contents

• 3" barrel Masuyama 80 eyepiece
• aluminum trunk case

 

Specifications:

Focal length:

80 mm

 

Field of view:

52°

 

Eyegard:

Rubber

 

Lenses / groups:

5 Lenses

 

Field stop:

70 mm

 

Coating:

Fully multicoated

 

Barrel size / Filter thread:

3"

 

Weight:

3,74 lbs

 

 

 

 

 

[25585]

So I wonder if @FLO will be stocking any.

[Horwig]

I shall start putting body pieces aside for eventual purchase

[John]

6 minutes ago, 25585 said:

So I wonder if @FLO will be stocking any.

Along with 3" diagonals and 3" filters ?

 

[25585]

15 minutes ago, John said:

Along with 3" diagonals and 3" filters ?

 

https://telescopes.net/store/explore-scientific-3-diagonal.html

TV make a 3" paracorr http://www.skyandtelescope.com/sky-and-telescope-magazine/beyond-the-printed-page/tele-vues-3-inch-paracorr/

Must be filters......

 

[Peter Drew]

I've made 2.5" Plossls of 80mm and 100mm focal length for special purposes. It's true that the seemingly "small" field of view, by current standards, really does appear to be much larger, probably something to do with the large lenses. If eyepieces get much bigger we won't need binoculars as both eyes will be able to look in.  

[Swoop1]

It wasn't murder M'Lud. The deceaseds eyepiece fell from his telescope, striking him a fatal blow to the head..........

[25585]

11 hours ago, Peter Drew said:

I've made 2.5" Plossls of 80mm and 100mm focal length for special purposes. It's true that the seemingly "small" field of view, by current standards, really does appear to be much larger, probably something to do with the large lenses. If eyepieces get much bigger we won't need binoculars as both eyes will be able to look in.  

Very true. We will need a face cup instead of an eye cup   My 40mm Maxview and 55mm TV plossl have almost window-like eye lenses. Its a shame mid-size SCTs and most Maks are really restricted to 1.25", as they would benefit as much as big SCTs.

Peter, have you any photos of your plossls?

[Ricochet]

I don't think I'd buy this eyepiece if I had a C11. Two grand for 1.5° is a lot of money, especially when the rear baffle is going to vignette the outer 0.5°. 

[alanjgreen]

23 minutes ago, Ricochet said:

I don't think I'd buy this eyepiece if I had a C11. Two grand for 1.5° is a lot of money, especially when the rear baffle is going to vignette the outer 0.5°. 

Yep, just mount a nice 80+mm frac on top for a lovely wide field. My Borg89 used to ride on top of the C11 to give best of both worlds  

[F15Rules]

Even if we could buy affordable 3" eyepieces, wouldn't the standard baffle spacing in refractors (which I guess is optimised for maximum 2" eyepieces?) interfere, ie. vignette the potentially wider view of the 3 inchers ? 

Dave

[Chris]

3" eyepieces....I'm not going there without a lottery win. Still, it would be cool to look through someone else's! 

[Alien 13]

I fancy one on my WO ZS71 it would mean chopping the tube and perhaps fitting a nice correct image prism of say 4 inch diameter with matching focusser...

Alan

[xtreemchaos]

I could never see myself using a 3inch ep, thay weigh morethan most scopes with no advantage over a 2inch no matter how thay jazz the wording and the price, id have to be dropped on my head as a kid many times and then id have to be drunk and a lottery winner to even dream about it . white elephant comes to mind.  thanks for the post, its interesting. charl.

[alan potts]

I do actually have one on my LX 200 but a balance system would most likely be needed as well with that amount of weight at the back.

Alan

[MarsG76]

Massive ... everything about this monster is massive, including the price...

And here I thought that my 31mm Nagler was massive...

[skybadger]

I used to use a big brass eyepiece with a 6" f/12 Cooke refractory dating from 1890. It gave a Mag of X32. Nice to see those eyepieces coming back.

[LukeSkywatcher]

I'm gonna need a bigger scope..........and bank balance. I'd probably also need to buy a Hubble telescope which FLO sell at a nice price.

[laowhoo]

On 1/16/2018 at 19:02, Peter Drew said:

I've made 2.5" Plossls of 80mm and 100mm focal length for special purposes. It's true that the seemingly "small" field of view, by current standards, really does appear to be much larger, probably something to do with the large lenses. If eyepieces get much bigger we won't need binoculars as both eyes will be able to look in.  

 

Peter, what FOV gain do you find in your binocular telescopes as versus the same EP in Cyclops mode? Have you ever quantified this? It's probably some standard formula in percentage?

[bingevader]

Oops, miss placed decimal point!

Do you think we could hold them to the 2.195 Euros?!

[Peter Drew]

2 hours ago, laowhoo said:

 

Peter, what FOV gain do you find in your binocular telescopes as versus the same EP in Cyclops mode? Have you ever quantified this? It's probably some standard formula in percentage?

There  shouldn't really be any difference, the apparent FOV of an eyepiece remains the same if used singly or in pairs. What I have noticed though, it is possible to slightly "stretch" the FOV to an oval before the overlap becomes two images so I suppose a few % extra could be claimed. The special eyepieces I made were mainly for high magnification views with a camera obscura which would typically have a 5metre focal length.

[laowhoo]

6 hours ago, Peter Drew said:

There  shouldn't really be any difference, the apparent FOV of an eyepiece remains the same if used singly or in pairs. What I have noticed though, it is possible to slightly "stretch" the FOV to an oval before the overlap becomes two images so I suppose a few % extra could be claimed. The special eyepieces I made were mainly for high magnification views with a camera obscura which would typically have a 5metre focal length.

 

I knew I'd seen it somewhere

http://arieotte-binoscopes.nl/Why a Binoscope.htm

3) Enlarged Field of View, but for the same EP it's only in the perception that's afforded by a sufficiently wide field stop (100*), whereby the combined peripheral vision of both eyes will make you feel you're seeing more.

Funny, but I didn't know Mel Bartels had addressed binoscopes. ("True binocular or two eyed viewing results in a half magnitude gain in stellar limiting magnitude and about a magnitude gain for extended objects.")

[alanjgreen]

Here's what Al Nagler thinks...

Q: There are a few 3" eyepieces on the market. Might this be the next frontier for visual amateur astronomy?

A: Except for providing long focal-ratio observatory refractors with a bit more true field capability, I see little other need for a long focal length, 3" format eyepiece. The size, weight, and cost just to gain a bit more true field isn't worth it with typical amateur refractors, and exit pupil limitations make it a non-starter with Newtonians. It would be more cost effective to buy a shorter focal length telescope! An f/3 Dob with a Paracorr and a 21mm Ethos will have almost twice the true field of view, better off-axis performance, and likely no need for a ladder compared to an equivalent aperture f/6 used with a 41mm Panoptic.

 

from https://astronomyconnect.com/forums/articles/a-q-a-with-al-nagler-looking-back-and-ahead-with-tele-vues-co-founder.58/

[25585]

Well he would say that

Having got a Fujinon X-T2 camera recently, and when going through its various menus, I came across settings to program it (depending on lens in use) for compensating for aspheric and pin cushion + other optical distortions. The EVF will show, in theory anyway, an optically perfect, completely correct colour-balanced image. 

To me a unit and dedicated eye pieces, perhaps with different modes, that can be used on any telescope, is the future of amateur astronomy, though it will not replace conventional optics but run alongside. 

My camera has a 90 deg flip screen so I will have a right way up viewer for frac & SCT so when using will not need a diagonal. Being mirrorless i.e. not a DSLR, my scope + an ep + body will give EV views & take images if I wish. 

The technology exists already for simple next gen amateur viewing. How great it will be to use a 120 deg ep, see the whole TFOV with both eyes, no strain or eye relief issues, sharp and flat. "I'll buy that for a dollar!"