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Tak TOEs 👉 Jupiter 🥂


Highburymark
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21 minutes ago, John said:

My observing eye is clearly not as acute as some here. I've compared my T2 BBHS prism with my AP and TV diagonals quite often and I just can't see any differences in performance in any of my refractors :rolleyes2:

Probably not much point in me trying a TOE - I probably won't see any differences over my current high power eyepieces !

I struggled to see much difference between a TMB Supermonocentric 5mm and a University Optics HD 5mm ortho when I had those in my eyepiece case. Only perhaps on the nights of very best seeing and then the differences were very subtle indeed.

 

Vision, the big unknown. Good point actually- John can you see the Double Double in Vega as 2 separate "stars" naked eye?

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21 minutes ago, jetstream said:

Vision, the big unknown. Good point actually- John can you see the Double Double in Vega as 2 separate "stars" naked eye?

I don't know, I've never tried. I suspect not but I'll have to try it at the next opportunity.

I think I used to be more fussy / ambitious / discerning over optical performance in the past than I am now. If I get nice views and occasionally see something that I've not seen before then I'm a happy camper :thumbright:

 

 

 

Edited by John
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With my astigmatism, I'm lucky to split  Mizar/Alcor naked eye (many moons ago, haven't tried recently).  The DD just looks like a single star to me naked eye.

I've found going up in aperture helps extract more detail than trying to buy exotic eyepieces.  Going from 4" to 8" to 15" makes a huge difference in what can be resolved.

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50 minutes ago, John said:

I don't know, I've never tried. I suspect not but I'll have to try it at the next opportunity.

I think I used to be more fussy / ambitious / discerning over optical performance in the past than I am now. If I get nice views and occasionally see something that I've not seen before then I'm a happy camper :thumbright:

 

 

 

Well you can see M33 naked eye so a 3.5arc min star separation should also be easy! Eagerly waiting reports and yes I easily see Epsilon Lyrae as 2 separated stars naked eye.

What I dont know is this- if a 3.5 arc min separation cant be seen naked eye, can the eye resolve more with a telescope? :dontknow:

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Seeing the 3' separation of the two pairs in ε Lyrae with the naked eye is not a very stringent test of naked eye acuity.

If you cannot see it as double, then you should make an appointment with the eye doctor, because your prescription is out of date.

I admit, I was in that camp--I could see them as an elongated single star.  I had my eyes tested and got a better prescription and Voilà!, there was a close, but easy, pair.

Ironically, those same glasses improved the view through all my eyepieces, too.

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1 hour ago, jetstream said:

Well you can see M33 naked eye so a 3.5arc min star separation should also be easy! Eagerly waiting reports and yes I easily see Epsilon Lyrae as 2 separated stars naked eye.

What I don't know is this- if a 3.5 arc min separation cant be seen naked eye, can the eye resolve more with a telescope? :dontknow:

Yes.  There are multiple reasons:

1) magnification.  A 1" separation at 180x is an effective 3' separation.

2) resolution.  1' is about the limit of resolution for the human eye.  A 4.5" telescope can resolve a 1" separation!

3) exit pupil.  Visual acuity is higher when the pupil used is smaller than the dark adapted pupil.  A 2-3mm exit pupil behind the eyepiece will allow your eye to resolve better than the full dark adapted pupil diameter.

Far fewer aberrations in the eye can be seen.

 

Many years ago, someone posted a chart I'll try to remember:

1' of arc--the limit of human vision

3' of arc--the typical limit for a person with good, but not superb, vision

4' of arc--the average resolution without strain--fairly easy for most experienced observers.

8' of arc--an easy resolution for the average eye without perfect correction of vision--just about everyone can see this easily.

How that translates:

a star with a 1" separation will be seen as double by the person with a resolution of:

1' at 60x

3' at 180x

4' at 240x

8' at 480x.

 

Perhaps that will give you an insight into why people need such radically different magnifications to split close double stars.

I can see ε Lyrae as double with the naked eye with glasses on.  In a scope, that translates to 78x to see all 4, and that is close to accurate--I can see all 4 stars at 83x fairly easily.

An easy split by everyone, though, might require 209x.  Certainly, seeing them all is much easier at the higher magnification.

People's eyes differ a lot, and scope quality and seeing can interfere as well, so there is no set magnification to see any double star.

 

 

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3 hours ago, Don Pensack said:

Yes.  There are multiple reasons:

1) magnification.  A 1" separation at 180x is an effective 3' separation.

2) resolution.  1' is about the limit of resolution for the human eye.  A 4.5" telescope can resolve a 1" separation!

3) exit pupil.  Visual acuity is higher when the pupil used is smaller than the dark adapted pupil.  A 2-3mm exit pupil behind the eyepiece will allow your eye to resolve better than the full dark adapted pupil diameter.

Far fewer aberrations in the eye can be seen.

 

Many years ago, someone posted a chart I'll try to remember:

1' of arc--the limit of human vision

3' of arc--the typical limit for a person with good, but not superb, vision

4' of arc--the average resolution without strain--fairly easy for most experienced observers.

8' of arc--an easy resolution for the average eye without perfect correction of vision--just about everyone can see this easily.

How that translates:

a star with a 1" separation will be seen as double by the person with a resolution of:

1' at 60x

3' at 180x

4' at 240x

8' at 480x.

 

Perhaps that will give you an insight into why people need such radically different magnifications to split close double stars.

I can see ε Lyrae as double with the naked eye with glasses on.  In a scope, that translates to 78x to see all 4, and that is close to accurate--I can see all 4 stars at 83x fairly easily.

An easy split by everyone, though, might require 209x.  Certainly, seeing them all is much easier at the higher magnification.

People's eyes differ a lot, and scope quality and seeing can interfere as well, so there is no set magnification to see any double star.

 

 

And as you may know the ∆ mag of the double can affect the resolution even though it's not a direct factor . It is the direct result of the size of the airy disc .

Evenly matched pairs are a good test for resolving power of eyes / telescope / seeing . 

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Really interesting thread.  I’ve really enjoyed watching the two gas giants across these last 6 weeks and am very pleased with my XW 5mm & 7mm, the latter has really exceeded all expectation I had. Was toying with the idea of a 6mm Fujiyama but certainly will keep my eye out for a 3.7mm HR too. I think a TOE wouldn’t see enough use in my dob for the outlay. 

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4 hours ago, Stardaze said:

Really interesting thread.  I’ve really enjoyed watching the two gas giants across these last 6 weeks and am very pleased with my XW 5mm & 7mm, the latter has really exceeded all expectation I had. Was toying with the idea of a 6mm Fujiyama but certainly will keep my eye out for a 3.7mm HR too. I think a TOE wouldn’t see enough use in my dob for the outlay. 

I’ve had a few Fujiyamas. Nice, clean eyepieces, but I couldn’t see any optical advantage over TV Plossls at longer focal lengths, and have just sold the 6mm as it wasn’t getting used. I definitely need more comfort from a planetary eyepiece when sustained observation is necessary to wait for those bursts of steady seeing. I only have the 5mm in the XW range, but I can see why they don’t come up often in the classifieds - beautiful eps and so comfortable to use.
It’s the comfort factor that really distinguishes the TOEs (and presumably HRs). You can forget you’re at the eyepiece and just concentrate on observing. In that respect, they are the ‘anti-orthos’. Have to credit Vixen for making the breakthrough. 

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31 minutes ago, Highburymark said:

I’ve had a few Fujiyamas. Nice, clean eyepieces, but I couldn’t see any optical advantage over TV Plossls at longer focal lengths, and have just sold the 6mm as it wasn’t getting used. I definitely need more comfort from a planetary eyepiece when sustained observation is necessary to wait for those bursts of steady seeing. I only have the 5mm in the XW range, but I can see why they don’t come up often in the classifieds - beautiful eps and so comfortable to use.
It’s the comfort factor that really distinguishes the TOEs (and presumably HRs). You can forget you’re at the eyepiece and just concentrate on observing. In that respect, they are the ‘anti-orthos’. Have to credit Vixen for making the breakthrough. 

Maybe I’ll hold out for an HR. Was going to add the XW 3.5 at some point but fancy trying something specific. 

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2 hours ago, Stardaze said:

Maybe I’ll hold out for an HR. Was going to add the XW 3.5 at some point but fancy trying something specific. 

I have the XW 3.5mm and it seems just as good as the 10, 7, and the 5mm. It's a pretty tall eyepiece though and sometimes I prefer the ergonomics of the little Nagler 2-4mm zoom.

 

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9 minutes ago, John said:

I have the XW 3.5mm and it seems just as good as the 10, 7, and the 5mm. It's a pretty tall eyepiece though and sometimes I prefer the ergonomics of the little Nagler 2-4mm zoom.

 

I find the 5mm quite long but those  small nag zooms do look handy John. It’s likely to be my least used EP I guess, but on those special nights, maybe..

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34 minutes ago, Stardaze said:

I find the 5mm quite long but those  small nag zooms do look handy John. It’s likely to be my least used EP I guess, but on those special nights, maybe..

I use the 2-4mm Nagler zoom far more than I ever thought I would. With my refractors, it's become my go-to high power eyepiece.

 

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On 25/09/2021 at 10:23, Stardaze said:

Really interesting thread.  I’ve really enjoyed watching the two gas giants across these last 6 weeks and am very pleased with my XW 5mm & 7mm, the latter has really exceeded all expectation I had. Was toying with the idea of a 6mm Fujiyama but certainly will keep my eye out for a 3.7mm HR too. I think a TOE wouldn’t see enough use in my dob for the outlay. 

I've ordered a 6mm Fujiyama which should arrive this week so no doubt the weather will be terrible!

I found that for high magnification planetary observing I don't particularly like wide fields or lots of eye relief so it'll be interesting to see how I get along with this and the 6mm focal length should be a good fit for my gear.

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I can offer a brief comparison of a prism (Tak 1.25") and a good 2" dielectric  (Old Baader Maxbright same mirror as Astrophyics) used in a F9.2 App refractor.

Most nights I can see no certain difference between the two diagonals to my eyes. On nights of good seeing  when using Brandons the Tak prism has less scatter and shows slightly more detail on for example Mars last year. The other main difference is that the prism shows reds better , like in the great red spot, compared to the dielectric. The saturation of reds seems to be a dielectric issue and apparently is not an issue with the Baader silver coated prisms.

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Thanks to Japanese efficiency, my 6mm Fujiyama ortho which had only left the factory on the 23rd and was dispatched from Kyoto on the 24th, arrived just after lunch on Monday and by some sort of miracle there was a long enough spell of clear skies for it to see first light a few hours ago.

I tried it with the following configurations of my little Tak:

FS-60Q - 60mm aperture, 600mm focal length (f10)

FC-76DCU - 76mm aperture, 570mm focal length (f7.5)

FC-76Q - 76mm aperture, 954mm focal length (f12.6)

I was able to view Jupiter and Saturn with the first two and the Moon with the latter using the 6mm ortho to give magnifications of 100x, 95x, and 159x respectively. Seeing was okay to begin with but worsened significantly towards midnight and I had clouds and reducing transparency to contend with as the night wore on. Despite this the little eyepiece delivered impressively sharp views of all targets with plenty of detail visible in Jupiter's atmosphere and the moons rendered more clearly as tiny disks than I've seen with any other eyepiece so far (BST 8mm, Nirvana 4mm, Hyperion Mk IV Zoom with and without 2.25x Barlow). Saturn was very low but some banding was visible and the shadow of the planet on the rings was surprisingly crisp in moments of better seeing. Unfortunately the Cassini Division was much harder to spot and far from clear when it was visible, but this was obviously the result of the planet's position in the sky rather than any shortcomings in the eyepiece.

It was too windy to bother with the longer FC-76Q outside but I set it up looking out of a bedroom window to observe the rising Moon around midnight. Seeing had deteriorated significantly and being indoors won't have helped, with the view of the Moon being obviously affected by the turbulent atmosphere even at just 27x magnification using a 36mm Plössl. Upping the mag to 159x using the 6mm ortho I was pleasantly surprised by the brief but absolutely razor sharp views it gave me during moments of better seeing that suggested both scope and eyepiece had plenty more to give. Unfortunately the appearance of fairly thick haze meant that this wasn't going to be the night to explore those limits.

To summarise if you don't mind the relatively narrow FOV (not an issue for planetary observing IMHO) and the contact lens-like eye relief then the little Fujiyama will deliver remarkable views in a tiny and lightweight package that's the perfect match for a small refractor or other lightweight grab-and-go scope. The price is a step up from budget eyepieces but I think it represents very good value for money given how well it performs, and I'm keen to try out some of their longer focal length orthos when funds permit.

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55 minutes ago, Andrew_B said:

To summarise if you don't mind the relatively narrow FOV (not an issue for planetary observing IMHO) and the contact lens-like eye relief then the little Fujiyama will deliver remarkable views in a tiny and lightweight package that's the perfect match for a small refractor or other lightweight grab-and-go scope.

Excellent that the Fuji is performing for you- I have a 7mm Fuji (KK) that rival my very best eyepieces. They are not only good in the grab and go mode but also in the dobs. My orthos are the goto for very faint, small objects and in the 24" the 7mm gives 357x, great for galaxies and PN. And yes the manual dobs easily tracks with them.

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11 hours ago, Andrew_B said:

Thanks to Japanese efficiency, my 6mm Fujiyama ortho which had only left the factory on the 23rd and was dispatched from Kyoto on the 24th, arrived just after lunch on Monday and by some sort of miracle there was a long enough spell of clear skies for it to see first light a few hours ago.

I tried it with the following configurations of my little Tak:

FS-60Q - 60mm aperture, 600mm focal length (f10)

FC-76DCU - 76mm aperture, 570mm focal length (f7.5)

FC-76Q - 76mm aperture, 954mm focal length (f12.6)

I was able to view Jupiter and Saturn with the first two and the Moon with the latter using the 6mm ortho to give magnifications of 100x, 95x, and 159x respectively. Seeing was okay to begin with but worsened significantly towards midnight and I had clouds and reducing transparency to contend with as the night wore on. Despite this the little eyepiece delivered impressively sharp views of all targets with plenty of detail visible in Jupiter's atmosphere and the moons rendered more clearly as tiny disks than I've seen with any other eyepiece so far (BST 8mm, Nirvana 4mm, Hyperion Mk IV Zoom with and without 2.25x Barlow). Saturn was very low but some banding was visible and the shadow of the planet on the rings was surprisingly crisp in moments of better seeing. Unfortunately the Cassini Division was much harder to spot and far from clear when it was visible, but this was obviously the result of the planet's position in the sky rather than any shortcomings in the eyepiece.

It was too windy to bother with the longer FC-76Q outside but I set it up looking out of a bedroom window to observe the rising Moon around midnight. Seeing had deteriorated significantly and being indoors won't have helped, with the view of the Moon being obviously affected by the turbulent atmosphere even at just 27x magnification using a 36mm Plössl. Upping the mag to 159x using the 6mm ortho I was pleasantly surprised by the brief but absolutely razor sharp views it gave me during moments of better seeing that suggested both scope and eyepiece had plenty more to give. Unfortunately the appearance of fairly thick haze meant that this wasn't going to be the night to explore those limits.

To summarise if you don't mind the relatively narrow FOV (not an issue for planetary observing IMHO) and the contact lens-like eye relief then the little Fujiyama will deliver remarkable views in a tiny and lightweight package that's the perfect match for a small refractor or other lightweight grab-and-go scope. The price is a step up from budget eyepieces but I think it represents very good value for money given how well it performs, and I'm keen to try out some of their longer focal length orthos when funds permit.

Great to hear your experience. The Fujiyama Or’s are excellent optically, if you can take the minimal ER and small FOV 👍🏻

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On 28/09/2021 at 14:29, JeremyS said:

Great to hear your experience. The Fujiyama Or’s are excellent optically, if you can take the minimal ER and small FOV 👍🏻

Thanks Jeremy.

I've now had the chance to give it a quick go in my little FS-60CB to look at some terrestrial targets and yet again the ortho has been impressive. It's super sharp and seems to get that little bit extra resolution and contrast out of the scope that I don't remember seeing before (although I should do a proper side by side comparison). That sharpness extends right to the edge of the FOV and distortion is non-existent, and in combination with the shallow DOF of the baby Tak it gives that perfect snap into focus that's a sign of good optics.

Edited by Andrew_B
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I had a chance a few years back to try Baader GO's vs Astro Hutech Orthos vs Fujiyama Orthos and found them practically identical in terms of optical performance. There were a few differences in focal plane position with some focal lengths though, which did cause a little confusion at times. The Fujiyama's were pretty much par focal though their range (I didn't try the 25mm though). The Astro Hutech's were not.

There were rumours when they were launched that the Tak Abbe Orthos might be from the same manufacturer as the Fujiyama's - I'm not sure if that has been confirmed or otherwise now ?

 

 

 

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