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New APM zoom eyepiece 7.7mm-15.4mm , 75° Constant FOV

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#476 Astronome66

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Posted 30 May 2022 - 01:38 PM

Markus:

 

Do you think it might be possible to modify or redesign the stray light protection to increase the AFOV?  I wonder if making it a 2 inch only eyepiece would provide some room for the stray light control and for an increase in AFOV.  The binoviewer and binocular telescope users wouldn't like that but others might.

 

Jon

Oh yeah! Count me in for that. 2” would actually be way better because we could alternate between our APM XWA 20 and the zoom without the need of fumbling with an adapter. No need for it to be 1.25” IMO waytogo.gif



#477 adamgali89

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Posted 30 May 2022 - 01:43 PM

Simply leave a 2”-1.25” adapter on the zoom :)

#478 Astronome66

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Posted 30 May 2022 - 04:59 PM

Yeah, I know . . . but adapters are so cludgy wink.gif



#479 pregulla

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Posted 31 May 2022 - 04:50 AM

Making it 2" would mean it would require 2" barlow, also would leave everyone with 1.25" focusers out. If I were to choose between 1.25" and 66 degrees or 2" and 75 dergrees, I would probably choose 1.25".


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#480 Starman81

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Posted 31 May 2022 - 05:46 AM

A 2" barrel only option is a pipe dream guys as even getting this 1.25" model made apparently had Markus agree to a 10,000 pc order. There just isn't that market for the 2" only barrel.

#481 Shinzawai

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Posted 31 May 2022 - 06:36 AM

A 2" barrel only option is a pipe dream guys as even getting this 1.25" model made apparently had Markus agree to a 10,000 pc order. There just isn't that market for the 2" only barrel.

I think, hope, that's a zero too many, otherwise APM wouldn't exactly be a small company if you have to prefund that, and/or would arguably be stuck with those zooms for time eternal.



#482 StarAlert

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Posted 31 May 2022 - 07:52 AM

A 2" barrel only option is a pipe dream guys as even getting this 1.25" model made apparently had Markus agree to a 10,000 pc order. There just isn't that market for the 2" only barrel.

That’s incorrect. He committed to buy 1,000. 


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#483 APM M.Ludes

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Posted 01 June 2022 - 06:11 AM

Hello Everybody

 

it is correct that I removed the 75 degree specs from the product side. U.O. was also able to remove the 75 degree print from the stock eyepieces.

 

I have meanwhile clamped the eyepiece on my measuring apparatus. I measure 66.5° apparent field of view at 10 and 12mm. At 7.7mm it may be just under 67° and at 15.4mm it is 65.9°.

 

If one had the calculation of the eyepiece, then one would certainly take the SGF from the calculation. I measure it by measuring the angle at which a laser shines into the eye lens and still comes through the eyepiece. This does not take into account the entrance pupil of the telescope, but that is not fixed anyway.

 

Everybody who pre-ordered has of course the right to cancel and ask for a refund. It was clearly my fault not to check this spec for that FOV , period :-(

 

 

It has not the promoted  75 degree, period

 

 

however I still defend this eyepiece as one of the best on the market, still very in-expensive compare to what it delivers.

 

It delivers :

- slim body for binoviewing

- conical top for binoviewing

- high eyerelief

- tread to use Dioptrix

- click stop

- great edge performanc even in F/3.6 dobsonian

- almost no refocusing

- superb overal performance

- very comfortable wide field view

 

sorry for any trouble coursed


Edited by APM M.Ludes, 01 June 2022 - 06:22 AM.

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#484 Mr.etrain

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Posted 01 June 2022 - 06:47 PM

Thanks Marcus for the clarification and honest response, it is appreciated.

I for one look forward to many wonderful views through the eyepiece you passionately created.

Life is short, soak it up!

Very Best,
Erik
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#485 Starman81

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Posted 01 June 2022 - 11:58 PM

Hello Everybody

 

it is correct that I removed the 75 degree specs from the product side. U.O. was also able to remove the 75 degree print from the stock eyepieces.

 

I have meanwhile clamped the eyepiece on my measuring apparatus. I measure 66.5° apparent field of view at 10 and 12mm. At 7.7mm it may be just under 67° and at 15.4mm it is 65.9°.

 

If one had the calculation of the eyepiece, then one would certainly take the SGF from the calculation. I measure it by measuring the angle at which a laser shines into the eye lens and still comes through the eyepiece. This does not take into account the entrance pupil of the telescope, but that is not fixed anyway.

 

Everybody who pre-ordered has of course the right to cancel and ask for a refund. It was clearly my fault not to check this spec for that FOV , period :-(

 

 

It has not the promoted  75 degree, period

 

 

however I still defend this eyepiece as one of the best on the market, still very in-expensive compare to what it delivers.

 

It delivers :

- slim body for binoviewing

- conical top for binoviewing

- high eyerelief

- tread to use Dioptrix

- click stop

- great edge performanc even in F/3.6 dobsonian

- almost no refocusing

- superb overal performance

- very comfortable wide field view

 

sorry for any trouble coursed

 

Markus can you or anyone else show us the eyepiece with the DioptRx attached? In the entire 18 months since this eyepiece went from design to manufacture we have never seen whether the thread on the eyepiece can successfully accommodate the DioptRx. 


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#486 Matthew Star

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Posted 04 June 2022 - 02:37 AM

Well, it is a bit dissapointing to read, the EP does not reach 75° overall.

The good news is, it is probably still the best Zoom EP with the largest FoV of 66° overall.

So I will keep my order .

Later I can decide if I still want the rest of the Baader Morphius EP's. 

 

Are all companies that honest about FoV specs.

Today, my APM 30mm 70° EP arrived and looking trough the lens gives me a larger view than with my WO SWAN 40mm 72° EP, so I have to see the result for myself.

Maybe I like APM's 66° just as much as the 70° of my Pentax EP's.


Edited by Matthew Star, 04 June 2022 - 05:56 AM.


#487 Jon Isaacs

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Posted 05 June 2022 - 07:54 PM

Well, it is a bit dissapointing to read, the EP does not reach 75° overall.

The good news is, it is probably still the best Zoom EP with the largest FoV of 66° overall.

So I will keep my order .

Later I can decide if I still want the rest of the Baader Morphius EP's. 

 

Are all companies that honest about FoV specs.

Today, my APM 30mm 70° EP arrived and looking trough the lens gives me a larger view than with my WO SWAN 40mm 72° EP, so I have to see the result for myself.

Maybe I like APM's 66° just as much as the 70° of my Pentax EP's.

 

I measured the APM 30 mm 70° UFF at 69.9° using the projected beam method. That's an average of three measurements. 

 

Jon


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#488 adamgali89

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Posted 06 June 2022 - 12:15 AM

That is happening again!? I belive no APM eyepiece will ever reach the FoV mentioned in the description. What a shame!

#489 Starman1

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Posted 06 June 2022 - 08:45 AM

That is happening again!? I believe no APM eyepiece will ever reach the FoV mentioned in the description. What a shame!

You really think there is a difference between 70° and 69.9°?

What if I told you that many, if not most, eyepieces don't have the apparent fields claimed by the companies that sell them?

http://astro-talks.r...2&t=1483#p41976

One well known brand of inexpensive Plössls advertises them as 50° eyepieces, yet the apparent fields vary from 45.7° to 51.8°, and that is not uncommon.

Pentax XWs average about 69°, and only one focal length gets up to 70°.

All the Baader Morpheus measure more than 76°, but one measures a couple degrees under.  

Even one degree of apparent field doesn't matter at all, but a tenth of a degree is completely inconsequential.


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#490 Traveler

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Posted 06 June 2022 - 09:05 AM

I think and hope adam made a little joke...


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#491 Matthew Star

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Posted 06 June 2022 - 12:34 PM

And a funny one it is.



#492 adamgali89

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Posted 06 June 2022 - 03:01 PM

Please feel my sarcasm :)
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#493 iseegeorgesstar

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Posted 07 June 2022 - 11:20 AM

Would a 2" version of this new zoom simply mean a bigger FOV or could it translate to better optical performance too?

 

Since the primary design of this EP was as stated for spotting scope. I'd be open to a 2" zoom EP only for astro but I could totally see how there's not enough buyers for one.



#494 thecelloronin

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Posted 07 June 2022 - 12:13 PM

I’m guessing the eyepieces have all been assembled and the ship has sailed on revisions, right?


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#495 duri_jk

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Posted 07 June 2022 - 02:34 PM

Let's assume that 2" barrel allows constant 75 degree AFOV, maybe Markus can design complementary barlow element ~1.8x that would screw on this EP. Using some extension rings between EP and Barlow can further increase barlow factor...

This can be compact solution allowing extended coverage and barlow designed specifically for EP can lead to high quality views. And maybe there is a market for 2 versions - current one, as well as 2" 75 AFOV. If the glass is same and diffrence is in housing only, production costs can be shared.



#496 macfly51

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Posted 07 June 2022 - 04:56 PM

Hi, 

 

Would a 2" version of this new zoom simply mean a bigger FOV 

A 2" barrel is not necessary at this focal length since : eyepiece focal length x AFOV < 1600 (i.e. 15 x 75 = 1275 in this case)

 

Besides, a 13mm Ethos is in 1"1/4 (1300) while the 17mm is in 2" (1700wink.gif



#497 KJL

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Posted 07 June 2022 - 05:10 PM

A 2" barrel is not necessary at this focal length since : eyepiece focal length x AFOV < 1600 (i.e. 15 x 75 = 1275 in this case)

 

Besides, a 13mm Ethos is in 1"1/4 (1300) while the 17mm is in 2" (1700wink.gif

I suspect iseegeorgesstar knows this.

 

The reason for the reduced-from-spec AFOV is that a field stop had to be inserted after-the-fact to reduce "internal stray light" for astronomical use.

 

The equivalent field stop for a hypothetical 2" version of this zoom might then allow it to reach the originally-intended 75º AFOV.

 

The dream is that the existing design could be "simply" expanded to 2", allowing it to come to market faster and satisfy the original promise of the zoom.

 

...

 

I am extremely doubtful if this was done that it would cost anywhere the original price. In fact, I wouldn't be surprised if it cost over 2-3x as much — high enough few would buy it and thus it will never see the light of day, at least not without simultaneously improving other aspects of the EP (eye relief, EOFB, AMD, etc).


Edited by KJL, 07 June 2022 - 05:12 PM.


#498 adamgali89

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Posted 08 June 2022 - 09:13 AM

Markus, any updated news regarding the rest shipment?



#499 thecelloronin

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Posted 08 June 2022 - 10:34 AM

Couple of questions here…

 

Would the spotting scope version benefit from this stray light suppression? If not, do we know whether the spotting scope version has implemented this ad-hoc field stop or not? Hence, is the SS version wider in terms of FOV? 
 

And, is this ad-hoc field stop evidence that this is NOT actually the Meopta zoom inside?



#500 Starman1

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Posted 08 June 2022 - 11:21 AM

We don't know who actually made the Meopta Zoom, but it is from a Czech company:

https://www.optics-p...lescopic sights.

It's unlikely that KUO made the Meopta zoom or it wouldn't have taken that long in development and it would have been available long ago under the Sky Rover brand name.

And Markus could have imported a smaller quantity under the APM aegis a long time ago.

So The APM Super Zoom is just what it seems--a new product.

 

As has been stated elsewhere, the spotting scope/binoculars version is identical optically.

 

We also do not know if the apparent field was reduced to prevent stray light.  That is mere conjecture.

We also do not know if the apparent field was actually reduced from the samples, since Markus didn't measure the samples.

 

A 2" version with larger lenses, field stops, and apparent field would be an entirely different eyepiece, so time to quit talking about something that isn't going to happen,

and enjoy what is coming.


Edited by Starman1, 08 June 2022 - 11:22 AM.

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