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APM 150ED review

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#201 salico

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Posted 11 August 2019 - 04:01 PM

 Just send the thing back. Either get your money back or have them send you another one. At $8000 it should be their priority to make you happy. Dispute the charges if they don't.

 

End of story...........

exactly


Edited by salico, 11 August 2019 - 04:02 PM.


#202 Mad Matt

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Posted 11 August 2019 - 04:10 PM

Greenflash, can you post the same refocused image from the other side. I don’t believe the Schmidt prism should be cutting into the on axis light cone like that. The 45deg and horizontal spikes are obviously diffraction effects from where the prism edges are cutting into the light cone. It would not be unnormal to see this off axis but on axis I believe the aperture should be round.

Edited by Mad Matt, 11 August 2019 - 04:11 PM.


#203 Gordon Rayner

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Posted 11 August 2019 - 11:36 PM

Re:  #197, above:

 

Several  WW II   types  have    roofed  Schmidt   45 deg.  deviation prisms, among them the  Busch design   Flak 10 x 80  and the Schneider Goettingen 25 x 105,  in both  of which the  roof line   cuts into the converging light cone  asymmetricaly.

 

The Photronics  12 x 96   used huge  silvered or aluminized   Schmidt  roof prisms  ,  plus  rhomboids.     The  Schmidt  roofline  is centered on the light cone, IIRC.   The glass path is  very long.    They may have  been forced to metallize the roof faces  because  of the use(?) of Bk-7,  instead of   BaK-4, perhaps retroactively(?). 


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#204 garret

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Posted 12 August 2019 - 05:17 AM

 Just send the thing back. Either get your money back or have them send you another one. At $8000 it should be their priority to make you happy. Dispute the charges if they don't.

 

End of story...........

Not a another one.

The APM 150 design uses Schmidt prisms which are way too small, you can see the gaps in the images of the unfocused star in post #199 and major intrusions in the lightpath in some images in post# 196, it is inherent to the design.

 

The prism support pads, the too small prism,  (rough?) Roof edge line running through the optical path... they all contribute to spikes, ghost images and flares in the view.

 

Return this telescope and order at APM their 152mm Binocular telescope with EMS erecting mirrors instead.

https://www.apm-tele...tml?info=362713

 

You pay about Euro 4500.= more... what you get more:

 

- 90 degree view

- protected silver coated mirrors made by Matsumoto

- 100% unobstructed optical lightpath

- highest possible contrast for a binocular telescope

-  3" FeatherTouch focusers

- very good spherical and overall colour correction (F8)

- 1.80 degree field with the 30mm UFF APM eyepieces (1200mm fl)


Edited by garret, 12 August 2019 - 05:21 AM.

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#205 Greenflash1

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Posted 12 August 2019 - 01:58 PM

Garret,
I hear you! Thanks for the valuable input!

Yes, spending some more $ could get to the next level of performance by cutting out the prisms for a start using a binoscope and the mirror based folding of the optical paths.

That APM binoscope you reference is quite heavy and would almost certainly require a pier mount and would be best suited for an observatory (someone correct me if I’m wrong)!

Provided the scratched/gouged can be replaced, the binocular APM 150 should still give pleasing views of DSO, and is reasonably portable to dark sites. I realize there are inherent limitations with the prism design, but this is often seen with binoculars of all kinds ( flare, glints, decreased contrast, etc).

Certainly the extra Euro 4500 for the binoscope gets you more, but the hidden costs or considerations are a pier mount (to deal with the higher mags and increased weight), and a permanent darksite to place an observatory.

If you already live in a great site and have an observatory, you would likely be going for the binoscope.

If you want to go to darksite, and do outreach etc the binoculars could be preferable.

Food for thought! Again thanks for the valuable input!

Geoff

Edited by Greenflash1, 12 August 2019 - 01:59 PM.


#206 ThomasM

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Posted 12 August 2019 - 02:50 PM

Not a another one.

The APM 150 design uses Schmidt prisms which are way too small, you can see the gaps in the images of the unfocused star in post #199 and major intrusions in the lightpath in some images in post# 196, it is inherent to the design.

 

The prism support pads, the too small prism,  (rough?) Roof edge line running through the optical path... they all contribute to spikes, ghost images and flares in the view.

In one of the early announcement it was stated that the APM 150 is designed for 40 mm light troughput, so it makes sense to use 2" eyepieces. I would therefore be surprised if the prisms are too small, there is an easy way ot check it out. Either put a flash lamp from the eyepiece side and put a while paper on the objective lens, then a circle with 150 mm  diameter should be visible. Another test, does the exit pupil looks perfectly round? If the prism cuts it should be visible in the exit pupil.


Edited by ThomasM, 12 August 2019 - 03:00 PM.

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#207 Greenflash1

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Posted 12 August 2019 - 03:08 PM

Exit pupil is cut even for 1.25 TV Delos

#208 salico

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Posted 12 August 2019 - 03:57 PM

I'd also go with a binocular telescope. But always have a buddy to help assembling;-)



#209 Gordon Rayner

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Posted 12 August 2019 - 10:00 PM

Re:  39  and #80,  above:  Mr.   Jones:

 

What were the  opinions  of the   "  two acquaintances"  who compared   ED  Fujinon 150  mm.  ( straight versions  or the 45 degree versions?)  with the   mentioned  Chinese   APM 's  or similar,   of this thread?

 

I have no  viewing   experience  with the   150mm   Fuji/Fujifilm   ED version   straight view,  nor with the 45 deg. deviation version.  

 

About  "limited sales of the  150mm.  Fujinon  straight ".    I sold and maintained   dozens   of the  early version  60-65  pound   150mm. Fuji  Meibo/Fujinon,  from about 1973  until   the  40-45 pound  version  appeared.   Yasuyuki  "Charley"  Nemoto,  RIP,  the US sales manager,  said that   the  40- 45  pound   MT  had/has the same optics  as the  1973-  early 1980's heavier version.    I have some experience with maintenance  of the  lighter  , later  version  MT  straight. 

 

I suppose that  hundreds  of the  early ones  were sold  worldwide,  mostly for fishing,  but some  for   border  surveillance  in the mideast.   Some have appeared, polished,   advertised  with  phony provenances  and wishful thinking  former   roles.



#210 garret

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Posted 13 August 2019 - 01:16 AM

Either put a flash lamp from the eyepiece side and put a while paper on the objective lens, then a circle with 150 mm  diameter should be visible. Another test, does the exit pupil looks perfectly round? If the prism cuts it should be visible in the exit pupil.

Yes indeed, forgotten that, I have done that some time ago to my APM 100 ED with several eyepieces, not with a flashlight but with an expanded laser beam: true aperture: 99+ mm, the image was a round disc, no cut-offs.

 

Garret van der Veen, The Netherlands



#211 garret

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Posted 13 August 2019 - 01:44 AM

 

 

That APM binoscope you reference is quite heavy and would almost certainly require a pier mount and would be best suited for an observatory (someone correct me if I’m wrong)!

 

Each 152mm OTA is about 11.7KG; each EMS mirror is approx. 700 grams; each OTA has a handlebar with brass counterweight: approx. 1.5kg...total weight almost 28 kilograms, yes that's 9 kg more then the 150mm APM binocular.

 

Maybe a 200mm binocular is what you are looking for: https://www.cloudyni...y/#entry9568924

grin.gif


Edited by garret, 13 August 2019 - 07:09 AM.


#212 ThomasM

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Posted 13 August 2019 - 09:01 AM

The rhombs are clean. The left Schmidt is a mirror image if the right one. Interestingly it too has a few spots of similar scufffing on the face over the cell supports, but the spots are all outside the cone. The crucial support right behind the face that sends the light to the rhomb is currently undamaged in the left Schmidt. The 2” eyepiece accommodation of this current design places additional stringency on the elements near the edges of the light cone. Still, the defects show on the edges of the pupil on the TV Delos series eyepieces (1.25” eyepiece barrel) as well as the 2” UFF APM eyepieces that come with the bino. I will include an artificial star image. It’s a 300 micron hole though, will do a 50, 75, 100, 150, and 200 micron series of artificial stars when that mask mask arrives. Defocused Jupiter shows the damage spots as dark or light diffraction zones on the edge of the defocussed image but I wasn’t able to photograph.

I only got aware of this pictures now, so it seems that the prisms are a little bit smaller than needed, I would guess that the effective aperture is 147 mm instead of of 150 mm, 2% in diameter, 4% in area. Is this a real issue? Stars will be 0.05 mag dimmer, 4 % is the difference in transmission between a very good ortho eyepiece and an Ethos, who will notice the difference?

 

On bright object the cuts will result in two spikes, as seen in the image taken in the focus. I have no idea if it will be an issue under normal conditions.


Edited by ThomasM, 13 August 2019 - 09:02 AM.


#213 Mr. Bill

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Posted 13 August 2019 - 11:13 AM

As I understand it, effective aperture shows the on axis illumination but doesn't tell anything about the rate of light drop off as you move toward the edge.



#214 garret

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Posted 13 August 2019 - 01:10 PM

Use eyepiece with large fieldstop, same size as the prism size, the prism size for the APM 150 is not specified... (it's 25 mm for the new APM 100 SD)


Edited by garret, 13 August 2019 - 01:12 PM.


#215 Beg

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Posted 15 August 2019 - 12:28 AM

Very interesting thread. On one hand stunning views and excellent performance that match much larger instruments as everybody has stated. And on the other hand a possible design flaw that everybody has noticed to a certain degree and will be unacceptable to some. On a very expensive instrument. Do a recall or live with it ??........... 



#216 garret

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Posted 15 August 2019 - 02:39 AM

If Oberwerk would introduce a 150mm binocular with an build-in 90 degree Erecting Mirror System (Matsumoto EMS) the days of the APM 150 are numbered.

 

 

But if you build-in all 4 mirrors in one closed body, designing a simple IPD adjuster isn't going to be easy, focusing can be done with a helical focuser in the eyepiece holder just like the current big binoculars. 



#217 range88

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Posted 15 August 2019 - 02:56 AM

If Oberwerk would introduce a 150mm binocular with an build-in 90 degree Erecting Mirror System (Matsumoto EMS) the days of the APM 150 are numbered.

 

 

But if you build-in all 4 mirrors in one closed body, designing a simple IPD adjuster isn't going to be easy, focusing can be done with a helical focuser in the eyepiece holder just like the current big binoculars. 

This is better left to DIY or custom-build . Factories will be very unlikely to produce EMS binos.



#218 garret

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Posted 15 August 2019 - 04:10 AM

On YouTube: The development of the EMS system by Mr. Matsumoto: https://www.youtube....h?v=jtuWIb7Dr8w


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#219 ricky64

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Posted 30 August 2019 - 10:11 AM

Would love to hear updates from anyone using these binoculars....
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#220 ZX12

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Posted 30 August 2019 - 03:01 PM

I will post more updates and comparisons of the APM150 binocular with various telescopes using a binoviewer soon.

 

Overall I am very pleased with the 150's, and ended up trading my Takahashi FS102 binoscope (for a superb Lunt 100Ha) back to the original owner because of the lack of use.

 

The Tak's were as near optically perfect as I have seen, but they cannot match the aperture advantage combined with the excellent sharpness of the APM150, particularly on DSO's.

Another advantage to the 150 is the ruggedness and ease of use, while binoscopes can be a bit fussy when changing between different observers.

 

MIke

 

 


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#221 ArsMachina

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Posted 30 August 2019 - 03:25 PM

I did built a 120mm Borg Binoscope with EMS and sold it as soon as APM announced the 150mm binocular.

I always wanted a 150mm bino with short focal length (for wide fields) and 2" support.

I can hardly wait for the moment when I put in my 32mm Kasai eyepieces for the first time.

I also own a set of downturned 17mm Ethos :-)

 

This will be the one and only instrument I need, but I am still holding on and waiting patiently (haha not really) for the 90° version - come on Markus ;-)

 

BTW. Does anyone know the diameter of the largest lens in a 21mm Ethos?

I am still thinking about converting a set of these for binocular use ...

 

Jochen



#222 Greenflash1

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Posted 30 August 2019 - 04:03 PM

Status of APM 150 marred right prism, Markus is getting a replacement prism in its holder sent to me. If I can’t install and align the new prism, the plan is then to send the whole thing to Germany to Wellenform. The defect ended up well inside the optical path and creates some issues with planets but not DSO. So far Santa Fe has had very poor seeing conditions, very unusual. Overall the performance is good on DSO for the few days I’ve had access to good seeing.

#223 Greenflash1

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Posted 30 August 2019 - 04:06 PM

I’m not too concerned about spikes, more the fact the prism was allowed through QC. Will keep posting updates.


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