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Vixen HR Eyepiece


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14 minutes ago, jetstream said:

A question however- why don't the extremely expensive eyepieces use these measures to control the stray light in them as well? Some of my expensive hyperwides have quite bad scatter....

Would you be comfortable saying which hyperwides Gerry?

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4 hours ago, 25585 said:

...John, does your AS own eye pieces? Perhaps if you all clubbed together it could buy a 3.4mm for you all to use?

 

BAS does have some eyepieces with the society scopes. Most of them seem to be rather old plossls or similar. To illustrate this point, the other evening when I reported on using the societies NGT 18 inch newtonian, which is F/4.5, the eyepiece in the drawtube for most of the night was one of these :undecided:

s-l500.jpg.540976b4008090fd06c230af8f2eb147.jpg

To be fair, the view in the centre of the field (where most people look) was not bad at all.

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5 hours ago, Piero said:

Shall we continue talking about these hypertinies HR, and leave the 100s to other threads?  ? 

I appreciate the need to keep to the subject of the thread and not go off on tangents but is it really not OK to ask a quick question of a comment made???

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2 hours ago, GavStar said:

I appreciate the need to keep to the subject of the thread and not go off on tangents but is it really not OK to ask a quick question of a comment made???

I would agree with you Gavin. I see no harm in it.

Many threads evolve to widen the discussion from time to time. I often see people pick up on a question, kick it about in a couple of posts, before the thread continues on its original merry way...

So long as a thread doesn’t head off in a completely different direction for evermore, I would endorse individuals being able to ask questions a thread provokes occasionally...

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So anyway...

In my own non-scientific way, I've been comparing the HRs to other (very) short EPs currently within my grasp - 2.5 T6 Nagler and (the shorter end of the) 2-4 Nagler Zoom. It's been pretty much as you might expect, I suppose, with each one offering the obvious advantages - keep in mind I'm strictly manual alt-az, so that does increase the value of FOV to some extent, I suppose. But they are all of course quite short and get limited opportunity to really shine.

Now, with the 3.4 HR, we're in 'regular use' territory. My 3.5 T6 Nagler has been a go-to ocular in fracs and newts alike and I'm starting to experiment with options providing more eye relief - if I like the 4mm DeLite, I may well add the 3mm and if I like the 10mm Pentax XW, then maybe the 3.5 from that range?

Personally, I suspect the HR won't replace any particular EP, it's more of a "ooh, it's looking good tonight, let's try the HR" thing. When it's worth it, you put up with the tight ER and FOV, otherwise not.

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6 hours ago, GavStar said:

I appreciate the need to keep to the subject of the thread and not go off on tangents but is it really not OK to ask a quick question of a comment made???

Sure, there is no problem with that. 

It's just that your questions were likely to derail the topic into a debate about how well or not TeleVue Ethos eyepieces control stray light. That's all. 

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5 hours ago, GavStar said:

I appreciate the need to keep to the subject of the thread and not go off on tangents but is it really not OK to ask a quick question of a comment made???

I'm curious as well Gavin but I think the thread should stick to the original topic of Vixen HR's and others of that type.

You can always start another thread on optical compromises with hyper wide eyepieces (TV and others) - should be quite an interesting one as they all have their "achillies heel" :)

Back on the topic in hand, I suspect Mike is quite correct - having a "top tier" short focal length eyepiece or two in the eyepiece case is great to really take advantage of the best seeing conditions but might not completely replace wider field tools even if the latter don't quite perform as well in absolute terms.

When I was comparing the TMB Supermonocentric 5mm with a University Optics HD 5mm Ortho I found performance pretty much equal except for the sessions where observing conditions were really good (say, around 10% of the time) and then the TMB SM just made it a little easier to see the most subtle and challenging planetary details. That, to me, was the difference between them, plus nowadays around £300 in cost !

The term "blows out of the water" has not been used in this thread as far as I know but I have to say that I'm wary of it when describing the differences between one excellent eyepiece and another - to me the "gap" has always been subtle.

Maybe I'm not fussy / discerning enough though :dontknow:

 

 

 

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I find the HR a rather uncommon eyepiece I have to say. 

The aspect that surprised me the most is how bright the image is for the associated exit pupil. I think we all agree that when one tries some eyepieces, s/he starts having a feeling about how bright the image is at a certain exit pupil. Well, to me this learning curve was a bit shaken when I tried the 2.4mm HR, as the delivered planetary views were almost as bright as my previous 5mm SLV. 

The second aspect is the highly precise control of light scattering. Essentially, it is the eyepiece with less light scatter I've ever looked through. I've never tried an SMC or XO or ZAOII though.

Finally, in terms of contrast / resolution on planetary targets including the Sun and Moon, I find that this eyepiece goes "deeper" than others I've tried. A comprehensive comparison using the same focal length is tricky because there aren't many eyepieces with a f.l. of 2.4mm. It was better than my SLV 5mm + VIP 2x or Zeiss barlow 2x using my TV-60. How much better? Well, it showed a few subtle details on Jupiter which appeared just washed with the SLV + barlow combo. These differences do not emerge in the first couple of minutes of observation, but one has to pay attention and be patient. Cooperative seeing is also required. 

Despite the rather long eye relief for those focal length, an AFOV of 42 degrees is small. Orthoscopics affectionados are fine with this, but my feeling is that most people would prefer an eyepiece with 50-70 AFOV degrees, particularly when using a telescope of medium / long focal length. 

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19 minutes ago, John said:

the differences between one excellent eyepiece and another - to me the "gap" has always been subtle.

I know it when I see it, even if I can't explain it. In the case of the HRs, I guess it's given me a basic understanding of what all the ortho fuss is about. Perhaps I should try a longer ortho to see what I think at lower mags. I don't think I'll ever forget about what an Ethos (or even a lowly Nagler) does, though.

14 minutes ago, Piero said:

most people would prefer an eyepiece with 50-70 AFOV degrees

Like he said. :happy9:

48 minutes ago, John said:

Maybe I'm not fussy / discerning enough though

We appreciate the effort. :thumbright:

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16 hours ago, Piero said:

 

Okay, no problem Mike! Thank you anyway. I will have a look when I get one! 

BTW, in my 2.4mm, the field stop is beyond the glass. :) 

That's what I was thinking, that this is a negative/positive design with an internal field stop.  As such, won't an observer have to measure transit time at the meridian and perform some calculations to back into the effective field stop diameter?

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16 hours ago, Piero said:

Just found this scheme which shows the stray light design and more detail about the 5:3 optical scheme. :) 

Source: https://www.vixen-astronomie.de/produkte/okulare/hr/ 

 

image.png

I can't let it pass.  "mangified"?  Seriously, Vixen, you make terrific eyepieces, but you really need a spell checker.  At least they're consistently misspelling it. ?

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3 minutes ago, Louis D said:

That's what I was thinking, that this is a negative/positive design with an internal field stop.  As such, won't an observer have to measure transit time at the meridian and perform some calculations to back into the effective field stop diameter?

Sure. That would be even better. :) 

The internal field stop seems still visible though *I think*

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My 3.4mm HR arrived today from tringastro. Great service with RM special delivery included in the price! :)  Both the top and bottom lenses are perfectly clean. 

Looking forward to its first light! 

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  • 2 weeks later...
On 25/05/2018 at 12:43, FLO said:

Unfortunately the 3.4mm HR has already sold out and we are advised no more are available ?

We don’t know when the next delivery will arrive but Vixen-UK say they will have an ETA for us sometime next week. 

We have just heard, more Vixen 3.4mm HR eyepieces are scheduled to arrive early July ?

Steve 

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On 31/05/2018 at 09:18, John said:

I'm curious as well Gavin but I think the thread should stick to the original topic of Vixen HR's and others of that type.

You can always start another thread on optical compromises with hyper wide eyepieces (TV and others) - should be quite an interesting one as they all have their "achillies heel" :)

Back on the topic in hand, I suspect Mike is quite correct - having a "top tier" short focal length eyepiece or two in the eyepiece case is great to really take advantage of the best seeing conditions but might not completely replace wider field tools even if the latter don't quite perform as well in absolute terms.

When I was comparing the TMB Supermonocentric 5mm with a University Optics HD 5mm Ortho I found performance pretty much equal except for the sessions where observing conditions were really good (say, around 10% of the time) and then the TMB SM just made it a little easier to see the most subtle and challenging planetary details. That, to me, was the difference between them, plus nowadays around £300 in cost !

The term "blows out of the water" has not been used in this thread as far as I know but I have to say that I'm wary of it when describing the differences between one excellent eyepiece and another - to me the "gap" has always been subtle.

Maybe I'm not fussy / discerning enough though :dontknow:

 

 

 

Your experience will never allow you to over exaggerate John,
and that is a fine discipline.

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  • 2 weeks later...
10 hours ago, GavStar said:

There are a couple of recent reports on CN (link attached) that the Pentax XW 3.5 outperforms the vixen HR 3.4 despite the extra glass in the Pentax.

https://www.cloudynights.com/topic/614302-vixen-hr-34/page-6

Seeing as I have a 3.5mm XW already, I guess I don't see the need to pick up a 3.4mm HR.  I rarely use it and have considered selling it because it's so hard looking around the floaters in my eye due to the tiny exit pupil at this magnification level.  Even in binoviewers they're still noticeable at this exit pupil level, just not show stopping as in monoviewing.

The 3.5mm XW is nice and dark, constrasty, and sharp.  It's noticeably better than barlowing the 7mm XW.  In star testing, the airy disc is tighter with less roughness around the edges in the 3.5mm.

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11 hours ago, GavStar said:

There are a couple of recent reports on CN (link attached) that the Pentax XW 3.5 outperforms the vixen HR 3.4 despite the extra glass in the Pentax.

https://www.cloudynights.com/topic/614302-vixen-hr-34/page-6

I'm tempted by Pentax (some how managed to miss trying them so far), although reading the CN link I'm not fully convinced they out perform the HR's? One of the two guys who did the straight comparison said he sent the HR back as a dud, and they own the others so might have a good idea of how it should perform, and the other said they needed to do further testing. 

I have no comparison, but I'm pleased with the bright, sharp, flat image of the HR in my fast little Tak. I can't notice scatter at all but I admit I don't have the best eye for detail. 

Talking of which I'm not convinced I'm skilled enough for this kind of testing, but if @John has the Pentax 3.5mm? I'd be willing to send him my 3.4mm HR for a couple of months if he fancied having a play?

  

  

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