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Review of APM 70mm & 82mm ED APO

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#51 Jawaid I. Abbasi

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Posted 05 August 2017 - 04:01 AM

... and as I realize that it makes sense to discuss and compare both the new 70mm ED Apo and the 82mm ED Apo here, can the administrator maybe retitle this thread accordingly ?? Thank you !!!

Let me know the title and will be changed



#52 Pinac

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Posted 05 August 2017 - 04:55 AM

Many thanks for the tips regarding the eyepiece clamping, Jeelan - I will see what I can do with my two left hands ... smile.gif

 

Re Kowa and APM 82:
yes, the weight difference is quite noticeable. Having the APM side by side with the Kowa, the latter seems even heavier than before (it is in fact roughly the same weight as an APM 100). The balance is better on the Kowa, though, the center of gravity is a bit further back than on the APM. On the tripod, the front-heaviness of the APM is easily compensated by sliding it backward on the adjustable metal "rails" that come with some mount models until it is balanced out.

 

The Kowa appears a bit more robust as an instrument (and it is fully water and dust proof, of course, which makes it more versatile than the APM). But just for astro use, the APM is lighter and easier to take along, same for handling and mounting / demounting, which may make it more attractive for people who like to travel light.

 

With identical eyepieces in the focusers and ready to use, the APM 82 is 1cm less wide, 1cm higher and about 3cm longer than the Kowa; so very similar dimensions overall.

 

And then there is the APM 70 - almost cute flowerred.gif and small and light, I like it already even before having seriously reviewed it. I really look forward to making direct comparisons of performance with the 82 (and with the Vixens, and the Kowa, of course).

 

With the Vixens, the 70, which has ED lenses whereas the 81 doesn't, there is for my eyes quite a difference in brightness. The 70 produces much less color fringing, of course, than the 81 where CA is almost always present, but at similar magnifications, the 81 produces a clearly brighter image and so sometimes has the advantage when it comes to detail recognition, e.g. on the moon. I also tend to go higher in magn. with the Vixen 81 than with the 70.

It will be interesting to see whether similar differences exist between the APM 70 ED and APM 82 ED (in theory, the objectives of the 82 have over 30 % more light gathering aera than those of the 70, if my recollection from the geometry lessons at school is still accurate).

 

cheers
Pinac

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#53 Jeelan

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Posted 05 August 2017 - 05:25 AM

Thank you very much for that detailed feedback Pinac!!

 

I doubt very much there would be as much a difference between the APM 70 and 82 as there is between the Vixen ED 70 and 81mm..

 

In terms of image quality, the faster optical system on the 70mm with its FPL-51 triplet should be comparative to the 82mm with its FPL-53 doublet arrangement.

 

The 70mm doesn't appeal to me because in my opinion it narrows down the options for eyepieces whilst still retaining reasonable exit pupil. For low power browsing through this type of binocular, my preference is to sit in the 20-25x band.

 

That means there are still some good options in the 18mm to 24mm FL eyepieces given the APM 82s are 470mm FL, all of which retain an exit pupil above 3mm.

 

With the APM 70's sitting at 400mm FL, you're starting to get exit pupil's below 3mm and reducing rapidly as you start increasing magnification into the 30's...

 

Mind you these are just my opinions and how i'm rationalising the differences between the two - different horses for courses of ofcourse.

 

cheers

Jeelan


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#54 Jeelan

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Posted 05 August 2017 - 05:26 AM

BTW can i ask how you ended up with 2 sets of Kowa 32x eyepieces? Those aren't available to buy separately from Kowa are they?

 

cheers

Jeelan


Edited by Jeelan, 05 August 2017 - 05:26 AM.


#55 range88

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Posted 05 August 2017 - 07:04 AM

Many thanks for the tips regarding the eyepiece clamping, Jeelan - I will see what I can do with my two left hands ... smile.gif

 

Re Kowa and APM 82:
yes, the weight difference is quite noticeable. Having the APM side by side with the Kowa, the latter seems even heavier than before (it is in fact roughly the same weight as an APM 100). The balance is better on the Kowa, though, the center of gravity is a bit further back than on the APM. On the tripod, the front-heaviness of the APM is easily compensated by sliding it backward on the adjustable metal "rails" that come with some mount models until it is balanced out.

 

The Kowa appears a bit more robust as an instrument (and it is fully water and dust proof, of course, which makes it more versatile than the APM). But just for astro use, the APM is lighter and easier to take along, same for handling and mounting / demounting, which may make it more attractive for people who like to travel light.

 

With identical eyepieces in the focusers and ready to use, the APM 82 is 1cm less wide, 1cm higher and about 3cm longer than the Kowa; so very similar dimensions overall.

 

And then there is the APM 70 - almost cute flowerred.gif and small and light, I like it already even before having seriously reviewed it. I really look forward to making direct comparisons of performance with the 82 (and with the Vixens, and the Kowa, of course).

 

With the Vixens, the 70, which has ED lenses whereas the 81 doesn't, there is for my eyes quite a difference in brightness. The 70 produces much less color fringing, of course, than the 81 where CA is almost always present, but at similar magnifications, the 81 produces a clearly brighter image and so sometimes has the advantage when it comes to detail recognition, e.g. on the moon. I also tend to go higher in magn. with the Vixen 81 than with the 70.

It will be interesting to see whether similar differences exist between the APM 70 ED and APM 82 ED (in theory, the objectives of the 82 have over 30 % more light gathering aera than those of the 70, if my recollection from the geometry lessons at school is still accurate).

 

cheers
Pinac

You got 2 pairs of identical Kowa eps? How's that happening?

It's so handy when comparing the optics of the two. But I doubt at this mag. can any real difference be detected.

May be using Siebet's shorter fl Kowa-ready eps will be the best option.

I am looking forward to your report. 



#56 Mr. Bill

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Posted 05 August 2017 - 10:21 AM

Thank you very much for that detailed feedback Pinac!!

 

I doubt very much there would be as much a difference between the APM 70 and 82 as there is between the Vixen ED 70 and 81mm..

 

In terms of image quality, the faster optical system on the 70mm with its FPL-51 triplet should be comparative to the 82mm with its FPL-53 doublet arrangement.

 

The 70mm doesn't appeal to me because in my opinion it narrows down the options for eyepieces whilst still retaining reasonable exit pupil. For low power browsing through this type of binocular, my preference is to sit in the 20-25x band.

 

That means there are still some good options in the 18mm to 24mm FL eyepieces given the APM 82s are 470mm FL, all of which retain an exit pupil above 3mm.

 

With the APM 70's sitting at 400mm FL, you're starting to get exit pupil's below 3mm and reducing rapidly as you start increasing magnification into the 30's...

 

Mind you these are just my opinions and how i'm rationalising the differences between the two - different horses for courses of ofcourse.

 

cheers

Jeelan

Agree with your reasoning if you are choosing to use just one binocular, but I plan on still using my Lunt 100s side by side so the 70s would make more sense to cover fov and exit pupil spectrum.

 

The 70s would give me 4+ degree fov and 17x for the BIG picture.



#57 Pinac

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Posted 05 August 2017 - 11:25 AM

Review of APM 70 ED Apo and 82 ED Apo – Part I

 

INTRODUCTION

This is a brief review of the newest additions to the line of APM binocular telescopes (BTs), the 70mm and 82mm, both in the 45 degree configuration.

 

If we only look at the market of  BTs with exchangeable eyepieces and leave the straight large and very large binoculars (e.g. from Docter, APM, Oberwerk, Opticron and others.) aside, these new APM instruments come into a market that has so far been served at its lower end by makes from e.g. Oberwerk, Orion, TS, Vixen etc., some of them denominated „non-Apo“ or „semi-Apo“, at its middle and higher segments by Vixen among others, and at its top end by offerings from companies like Kowa (Highlander), Binoptic or Borg.

With its  denomination as „ED Apo“ and its prices around and above the € 2'000 level, it is apparent that the APM 70 and 82 are targeting the upper end of the market, and the segment so far „owned“ by Vixen and Kowa in particular. While I do not believe that Binoptic will be much affected by the new APMs,  Vixen and Kowa and possibly even Borg will likely get to feel that new competition.

 

APM has had a 100mm ED Apo (as well as a non-Apo version) on the market for some time which seems to have had an excellent success for this size instrument, has recently also launched a 120mm ED Apo version which has received very good reviews as well, and also offers a 150mm BT (semi-Apo). I have not had a chance to use or review any of these larger APM BTs (for reasons of weight and handling, I prefer to stay with around 80mm instruments as the upper end of how large I go) , and I have to admit that I was always a bit sceptical about certain remarks in internet fora that APM is going to make the Vixens and Kowas of this world into „collectors items“ or - more bluntly - „obsolete“. Owning both Vixens and Kowa, my attitude so far was: „well, let’s see if that is so“ (APM 100 and 120 users: leniency, please ;-)

 

This review is therefore intended to find out how the APM 70 and 82 perform, in particular when compared to BTs like Vixen 70 ED and Vixen 81 or the Kowa Highlander.

My review is written in two parts, mainly due to the current uncertain weather conditions at my location which have so far only allowed an occasional use of the instruments  under the night sky, so more observation time will be needed to come to more definitive conclusions as to the optical quality of the new APMs

Views from other users, both on my impressions reflected below and on subjects not mentioned here, will be very highly appreciated.

 

GENERAL

The two APM BTs come in a cardboard box with ample shock absorption foam material inside. I find this quite ok for both storage and transport and don’t need an additonal case (e.g. the nice metal case you get for the Docter), although the box does not allow transporting the BTs with the eyepieces inserted unless you cut out space for the eyepieces yourself.
The Vixens and the Kowa all come in similar cadboard boxes, although not as well padded as the APM.

 

Both APMs come with a pair of APM 18mm ultraflat eyepieces, producing 22x in the APM 70 and 26x in the APM 82.

The Vixens come without eyepieces (unless you buy one of the BT sets including eyepieces and tripod/mount offered by some dealers). The Kowa comes with 14mm (70 degrees) eyepieces giving 32x magn, and you can buy optionally pairs of 21mm (21x) and 9mm (50x) eyepieces.
((Remark: the Kowa eyepieces have a 1.25``diameter like those of the Vixens and APM, but use a special design – you can use them in other BTs, but „regular“ 1.25``eyepieces don’t fit into the Kowa Highlander ! – I find the Kowa eps very good, but they are VERY expensive))

 

As to the APMs:

 

APM 70
- Focal length: 400mm, f/5.7
- IPD: 54-76mm
- Max FOV: 4 degrees
- Weight w/o eyepieces: 3`765g (measured)

 

APM 82
- Focal length: 470mm, f/5.7
- IPD: 54-76mm
- Max FOV: 3.4 degrees
- Weight w/o eyepieces: 4`586g (measured)

 

Comparing dimensions with Vixen and Kowa, see photo. The APM 70 is clearly the most compact, the longest being the Vixen 81.
The Kowa with around 6kg is by far the heaviest, the APM 82 comes next, followed by the Vixen 81 and the Vixen 70.
The Vixen 70 is not only clearly the lightest, it also the best balenced when held with the handle or when mounted. The Kowa is also quite well belanced, the two Vixens are slightly front-heavy, the APM 82 is distinctly front-heavy, even with eyepieces inserted (see earlier contributions in this thread how to deal with that).

 

 

MECHANICS

Almost (see below) everything works well, smoothly and makes a well finished impression, from adapting the IPD to focusing on the two focusers to extending the dew shields or mounting the objective caps.

But: my samples of the APM 70 and the APM 82 „sit at opposite ends“ when it comes to how tightly the eyepieces fit into their clamping rings. Whereas eyepieces glide very easily into the eyepiece holders of the APM 70, where they then sit quite loosely, the opposite is true for the APM 82, eyepieces are very hard to insert, some slightly better than others (that’s the time you find out that not all 1.25``eps are actually really the same size !!),

APM immediately offered to change my 82 against another one when I reported the problem, but things have since eased with continued use, and now all those eyepieces which I intend to use with the 82 do fit in.

 

The big surprise with this experience – loose eyepieces in the 70, tight ones in the 82: it does not affect collimation at all.
Whereas I often have to slightly move, turn or even change eyepieces from left tube to right tube with my Vixens to get good image collimation, nothing of this is necessary with both APMs.
I seem to be quite sensitive to miscollimation, and I once sent my Highlander to Kowa because I felt collimation was not perfect. It came back better, but when I compare both at 32x and 50x with the APM 70 or the APM 82 at similar magnifications, I get the more perfectly collimated images with the APMs ! Even up to 80x on the 70mm and 94x on the 82mm, collimation remains impeccable. I have to admit that I am very positively impressed by this.

 

OPTICS / INITIAL IMPRESSIONS (daylight mostly)

 

Both APMs appear well blackened inside when viewed from the front end.

 

A view of the exit pupils reveals quite a comfortable situation: no false pupils, just a little bit of lighted „structures“ around the EP, but nothing dramatic, and well rounded EPs. The Vixen 70 exhibits a distinct false pupil, the Kowa a slightly truncated EP.

See photos.

 

Both APMs exhibit bright images, sharp and with good contrast, with no CA in the central parts of the image and very little at the edge.
The Vixen 81 is out of comparison here, with lots of CA at almost any magnification, although I so far liked it for the brightness of its image when compared to theVixen 70 (the latter shows much less color fringes than the 81, but at higher magnifications the image gets quite dark).
But with the arrival of the two APMs, this becomes a different game. Now you want both brightness and no color fringes, and you get it.
More detailed (nighttime) comparisons will follow to determine whether, and if yes, how much brighter and / or sharper the APM 82 is against the APM 70. So far, the only thing I can say is that both APMs range above the Vixens in terms of brightness, central sharpness, contrast, clarity and „calmness“ of the image., and off-axis sharpness.
During a very brief comparison last night when the moon was out for a moment between the clouds, I had the Kowa and the APM 82 out together, and both exhibited very similar images of excellent quality. There was no ghosting in either bino. I imagined that the APM could even have been slightly brighter than the Kowa, maybe only a nuance. On the other hand, the Kowa seemed just a nuance better in terms of color fringes at the edge of the moon. None of the two binos exhibited any CA in the central parts of the FOV.

This will all need to be retested and reconfirmed to be certain. but still shows that the APM 82, at about half the price of the Kowa, brings a superb performance for ist cost (again, subject to more detailed testing over the coming weeks), and after the first brief uses I expect nothing less from the 70mm.

 

PRELIMINARY IMPRESSION

While the new APMs may not be entirely perfect yet from a mechanical perspective (fitting of eyepieces), something I imagine will be improved as quality control gets better, I am very positively impressed by their optical performance (and I look forward to further reviewing it under the night sky). Those using the APM 100 or 120 may not find this surprising, but for me, the image quality of the APM 70 and 82 is surprisingly good, esp. based on my comparisons with the Vixens, but also the Kowa. For the moment, maybe brand recognition is a plus for Vixen and Kowa, but this can change quickly. It will be interesting to see how this market develops.

 

More to follow.

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Edited by Pinac, 05 August 2017 - 02:49 PM.

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#58 Pinac

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Posted 05 August 2017 - 11:29 AM

EP of APM 70

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#59 Pinac

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Posted 05 August 2017 - 11:30 AM

EP of APM 82

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#60 Pinac

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Posted 05 August 2017 - 11:31 AM

EP of Vixen 70ED

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#61 Pinac

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Posted 05 August 2017 - 11:31 AM

EP of Kowa Highlander

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#62 Pinac

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Posted 05 August 2017 - 11:34 AM

BTW can i ask how you ended up with 2 sets of Kowa 32x eyepieces? Those aren't available to buy separately from Kowa are they?

Yes, they are (but I got mine "by accident")



#63 Pinac

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Posted 05 August 2017 - 11:38 AM

You got 2 pairs of identical Kowa eps? How's that happening?

 

That's a very long story, something for dark and stormy winter nights .... wink.gif


Edited by Pinac, 05 August 2017 - 11:38 AM.


#64 Jawaid I. Abbasi

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Posted 05 August 2017 - 12:52 PM

Kowa has darker and almost no reflection or did you take picture in slightly different angle and  in darker room ??



#65 Pinac

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Posted 05 August 2017 - 02:37 PM

No, same room and lighting, photo unfortunalely not very sharp, but Kowa looks a bit better than APMs, almost no bright areas or structures/reflections around the EP, and no false pupil; the only criticism would concern that the EP is not perfectly round. If I had to rate it, Kowa would be best, followed by APMs (still good), followed by Vixen (slightly less good). 


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#66 Pinac

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Posted 05 August 2017 - 02:44 PM

.....

 

I doubt very much there would be as much a difference [[ in brightness, P. ]]between the APM 70 and 82 as there is between the Vixen ED 70 and 81mm..

 

In terms of image quality, the faster optical system on the 70mm with its FPL-51 triplet should be comparative to the 82mm with its FPL-53 doublet arrangement.

.....

.....

I believe you are right with both your statements, Jeelan, although I haven't really verified it yet.

And should this be confirmed, I would definitely go with the 70 and pass on the 82 (I originally imagined I would do it the other way around). Well, let's see.

Pinac



#67 Rich V.

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Posted 05 August 2017 - 03:12 PM

Pinac, just wondering if there is there a stray light baffle located at the objective side of the main Schmidt prism in the APMs?

 

Also, I can't tell for sure in the photo of the Highlander EP but it looks like there may be an aperture mask located between the main prism and the rhomb turret that is blocking the prism reflections that are so clearly seen in the other BTs.  The exit pupil of my Miyauchis is free of any reflections also but I know for sure there is a baffle located between the prisms to block off axis light. I'm curious if Kowa used a similar design to block reflections (if at the expense of some off axis illumination).

 

A photo of the baffle I'm speaking of:

 

118_1864.JPG



#68 Jeelan

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Posted 05 August 2017 - 10:11 PM

wow i didnt realise the difference between the 82's and 70's was that 

 

Review of APM 70 ED Apo and 82 ED Apo – Part I

 

 

Your pictures really highlight the size difference between the 82mm and the 70mm.... its quite substantial isn't it?

 

In view of that, I can see the appeal the 70mm would have for travel and portability.


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#69 Pinac

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Posted 06 August 2017 - 03:25 PM

Pinac, just wondering if there is there a stray light baffle located at the objective side of the main Schmidt prism in the APMs?

 

Also, I can't tell for sure in the photo of the Highlander EP but it looks like there may be an aperture mask located between the main prism and the rhomb turret that is blocking the prism reflections that are so clearly seen in the other BTs.  The exit pupil of my Miyauchis is free of any reflections also but I know for sure there is a baffle located between the prisms to block off axis light. I'm curious if Kowa used a similar design to block reflections (if at the expense of some off axis illumination).

 

A photo of the baffle I'm speaking of:

 

attachicon.gif118_1864.JPG

Not sure I can give you answers by just looking through the tubes from both sides, eyepieces removed, you seem to have opened your Miyauchis to make that photo and I hesitate opening my binos outside of an emergency (each time I open something mechanical that has 4 screws, when I am finished re-assembling and rescrewing the 4 screws, there are at least two more screws left that don't fit anywhere)

But if it can be done without opening, please tell me how.


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#70 Pinac

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Posted 06 August 2017 - 03:28 PM

wow i didnt realise the difference between the 82's and 70's was that 

 

 

Your pictures really highlight the size difference between the 82mm and the 70mm.... its quite substantial isn't it?

In view of that, I can see the appeal the 70mm would have for travel and portability.

Yes, the difference is substantial.

Whereas the 82 are the size you would expect an 82 bino to be, the 70 seems tiny, you wonder how it can provide the nice views without being bigger. It is definitely smaller than it looks in the pictures on the APM website.

My initial observations seem to tell me that the 82 will go a bit deeper on faint objects in the night sky, so there may be a certain trade-off between size/portability and performance (which you might expect). How big a trade-off? I hope to get answers over the coming days.


Edited by Pinac, 06 August 2017 - 03:38 PM.


#71 Jawaid I. Abbasi

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Posted 06 August 2017 - 04:34 PM

each time I open something mechanical that has 4 screws, when I am finished re-assembling and rescrewing the 4 screws, there are at least two more screws left that don't fit anywhere)

lol.gif



#72 Rich V.

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Posted 06 August 2017 - 05:25 PM

 

Pinac, just wondering if there is there a stray light baffle located at the objective side of the main Schmidt prism in the APMs?

 

Also, I can't tell for sure in the photo of the Highlander EP but it looks like there may be an aperture mask located between the main prism and the rhomb turret that is blocking the prism reflections that are so clearly seen in the other BTs.  The exit pupil of my Miyauchis is free of any reflections also but I know for sure there is a baffle located between the prisms to block off axis light. I'm curious if Kowa used a similar design to block reflections (if at the expense of some off axis illumination).

 

A photo of the baffle I'm speaking of:

 

attachicon.gif118_1864.JPG

Not sure I can give you answers by just looking through the tubes from both sides, eyepieces removed, you seem to have opened your Miyauchis to make that photo and I hesitate opening my binos outside of an emergency (each time I open something mechanical that has 4 screws, when I am finished re-assembling and rescrewing the 4 screws, there are at least two more screws left that don't fit anywhere)

But if it can be done without opening, please tell me how.

 

Please pardon my curiosity;  I can't help having questions about different BT designs and their whys and wherefores.   wink.gif     No, please don't open the Kowa unless you need to.  I had the Miyas opened up to collimate them so I took a couple of pics for documentation.    

 

I've only looked at and through a Kowa once and that was years ago when they first came out.  I didn't know to look at the subtleties at the time.  smile.gif  

 

Your photos looking into the eyepieces of the APMs and Vixens clearly show the prism face reflections around the exit pupils; no baffles. In the Kowas, though, the prism faces strangely can't be seen.  To me, they appear to have a baffle blocking the line of sight into the prism faces.  Perhaps if you look into the focuser without an eyepiece and move your eye around, you'll see the baffle more easily.

 

The Miyas look similar to the Kowas, I think. Here's a couple of photos; one shot off axis to show the baffle location relative to the prisms.  The on axis shot isn't as bright as yours of the Kowa but the baffle can be seen easily enough, I hope.  It's outside and concentric with the image of the objective.  I took these photos back when we were having the discussions of the false pupils in BTs several years ago.

 

Thanks

 

Rich

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#73 Pinac

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Posted 07 August 2017 - 11:09 AM

Here are two more photos of the Kowa EPs

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#74 Pinac

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Posted 07 August 2017 - 11:10 AM

.... and number two

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#75 Rich V.

Rich V.

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  • Joined: 02 Jan 2005
  • Loc: Lake Tahoe area, Nevada

Posted 07 August 2017 - 11:31 AM

Thanks for the effort, Pinac, it sure looks like the Kowas have incorporated a baffle; the prism reflections are very much weakened compared to the other BTs.  As you further compare, I'm curious if the edge illumination appears to fall off in the Kowas compared to the APMs or Vixens.

 

Looking forward to your further comparisons of these BTs under the stars.

 

Rich




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