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#1 Mad Matt

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Posted 12 February 2016 - 05:19 PM

...lets see who can figure out what I have done to my 22x85's   :bigshock:

 

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Edited by Mad Matt, 12 February 2016 - 05:24 PM.


#2 janapier

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Posted 12 February 2016 - 05:37 PM

Judging from "Frankenbino" in your sig and "10x50" on the backplate, you put it together from two binos.


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#3 Gucky

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Posted 12 February 2016 - 05:37 PM

It's pointing towards gravitational waves.


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#4 coopman

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Posted 12 February 2016 - 05:39 PM

Added a finderscope bracket to one of the dew shields?



#5 Mad Matt

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Posted 12 February 2016 - 05:42 PM

janapier wins... I grafted my 22x85 to my Lunt 10x50's... The result is un-be-liev-able!!! The field flatteners and eyepieces in the Lunts (lets call them BA8+) harmonize exceptionally well with the classic 22x85 BA8. I now have no problems with eye relief and have sharp stars at least 80% to the edge!

 

If Markus wont bring out the Lunt 20x80's... Why I'll just have to make my own!!!

 

I am extremely happy with how they turned out!


Edited by Mad Matt, 12 February 2016 - 06:02 PM.

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#6 Mad Matt

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Posted 12 February 2016 - 05:58 PM

and for anyone who cares... Here is a picture of the Lunt prism assembly The red arrow is a Smyth lens. It is interesting to note that the Smyth lens does not focus with the rest of the eyepiece. It is held to the focuser shelf by two very tiny screws that the yellow arrow points too.

 

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#7 Mad Matt

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Posted 12 February 2016 - 05:59 PM

Added a finderscope bracket to one of the dew shields?

 

Oh, yea, also did that at some point  :grin:



#8 Rich V.

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Posted 12 February 2016 - 08:58 PM

Wow, that should work on my WO 22x70s too!  Eye relief is the main issue with them but if the FF could make the edges more like my Fuji 16x70s that would be great.  What modifications were needed to fit the Lunt assy onto the BA8s?

 

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#9 Mad Matt

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Posted 13 February 2016 - 02:41 AM

Wow, that should work on my WO 22x70s too!  Eye relief is the main issue with them but if the FF could make the edges more like my Fuji 16x70s that would be great.  What modifications were needed to fit the Lunt assy onto the BA8s?

 

Rich

 

Yes, it should work. I did not have to modify the binocular housing. The modification is plug and play. 

 

There are a few things to note:

 

  1.  I had to unthread the objective lens cell assembly about 7mm to effectively move the focal plane forwards 7mm. You may not need to do this, I believe my focal plane was too far back with to begin with as I was at +5 when focused at infinity originally.
  2. The covers for the adjustment screws are pressed in Aluminium plugs. I had to carefully drill a 2mm hole though the center of each on in order to remove them. I will eventually fill in the holes with black silicone.
  3. You will loose collimation. I personal am ok with conditional alignment as I am the  only user of these. I actually think that collimating each tube for minimum aberrations and then conditionally aligning for your IPD gives a much better image then true collimation across the IPD range.

Other then the plugs mentioned above the process is reversible... also the BA8 prism /eyepiece assembly also fits on the Lunts. It is a very snug fit and needs a little gentile persuasion but it does fit. I only did a quick test... They of course loose the flat field but the image is still quite useful. I plan on using them in conjunction with the 22x85 as a "scouting device".

 

The magnification and FOV is seems to be within a few % of the original eyepieces. I initial had only one side converted so that I could do an A/B comparison and I could actually get the images to merge with the different eyepieces. I will try to do a precise EP measurement and post the results. 



#10 Mad Matt

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Posted 13 February 2016 - 04:51 AM

I measured the EP with calipers and it seems to be between 4.0-4.1mm which (assuming a full aperture of 84mm) puts me between 20.5x and 21x. Slightly less than the original but not noticeable.



#11 F.Meiresonne

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Posted 13 February 2016 - 09:13 AM

Phew, quite an achievement...

 

How you were sure it would al fit without too much hassle...?

 

Maybe you can send it to Kunming...to take it in production...The MM series.. :grin:  designed in Germany! 21x85 flat field bino... :grin:

 

Well, maybe more then 50% of the quality is made by the eyepieces imo, reason enough to get high end eyepieces on a bino with interchangeble eyepieces..


Edited by F.Meiresonne, 13 February 2016 - 09:16 AM.


#12 Mad Matt

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Posted 15 February 2016 - 03:22 AM

Here are a few impressions I was able gather between the clouds and rain we have been getting lately. These observations where done from my highly light polluted driveway.

 

  • M42 - All 4 stars in the Trapezium visible. They are separated until about 80% of the FOV and then the B component starts to fade away. Nice structure in Core nebula.
  • Pleiades - The cluster filled the central 60% of the AFOV and all the stars were sharp!!! This was not the case with the previous eyepieces.
  • Jupiter - Only about 30° above the horizon. A little flaring was visible but could be almost entirely eliminated with careful eye positioning. SEB and NEB where clearly visible. I could not specifically detect any structure but I "felt" they where not uniform. GRS was not in transit.
  • Moon - WOW! the sliver of first quarter moon was very nice as 20x. I was very surprised at the level of detail I could see at 21x. The magnification and my eyes seem to be the limiting factor for resolution which is how it should be. False color was noticeable but could almost be completely eliminated with careful eye positioning. I let the moon drift to the field stop and was surprised how well it held up. Lateral color was well controlled and I could accommodate for the field curvature almost to the edge.  

To sum up the results of the transplantation:

  1. On axis sharpness has remained the same. The slight astigmatism in my eyes being the limiting factor here.
  2. The instrument now has a "top class" flat field. The Smyth lens eyepiece design (8 Elements in 5 Groups) is probably very similar to the Nagler 2 design but trading a smaller AFOV for more Eye Relief. I still need to do a side by side comparison but I would say the field flatness is better then my APM with 24 ES 68°.
  3. The generous eye relief make observing with them a very relaxed and captive experience.
  4. Refections have remained at the same very low level. I find the the internal baffling of the BA8's to be quite good and the prisms have covers above the reflective prism faces. The Smyth lens group does not introduce an reflections. Falls pupils are not noticeable.

I know it will be hard to believe (and hard for me to say) but I feel the 21x85 Frankenbino now outperforms my beloved Fujinon 16x70. This is not only because the addition aperture and magnification but also the aesthetic impression of bright stars is slightly better in the 21x85. Supporting this is also the impression that there is much less flaring on Jupiter in the Frankenbino. I suspect that my Fujinons are just barely within the Fuji quality standards as I see a lot of spikes on bright stars, some of which are due to my eyes. It is more of a "Cosmetic issue", I have never assessed the double star resolution with them but I can see 4 stars in the trapezium so they cant be that bad.

 

What about the Lunt/BA8 10x50's you ask? Well I have them aligned and ready to test. A daytime comparison with my CZJ 10x50 shows the on axis sharpness to be equal with the field flatness being slightly better in the Lunt/BA8's. The BA8 Eyepieces actually work better handheld with the 10x50's because I can push the eyepieces against my face and the sit perfectly and provide a nice stable view. Doing this with the mounted 22x85's was not that comfortable and introduced vibration.

 

This is a rare instance case where the sum of the parts is more than the parts themselves. I invested about €850 and 4-5 hours of work in both binoculars. The two resulting binoculars would probably compare very favorably to the Lunt 20x70s and BA8 10x50 which have a combined retail of €1108,-. Win-Win if you ask me :-) 


Edited by Mad Matt, 15 February 2016 - 03:33 AM.

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#13 F.Meiresonne

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Posted 15 February 2016 - 02:24 PM

Impressive, most impressive!

 

Of course with the better eyepieces it's normal the BA8 performs still alot better ...

It must have become an impressive binocular ... i envie you! But i am glad you can enjoy it.

 

Clear skies!



#14 F.Meiresonne

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Posted 15 February 2016 - 03:14 PM

•M42 - All 4 stars in the Trapezium visible. They are separated until about 80% of the FOV and then the B component starts to fade away. Nice structure in Core nebula

 

I saw it too...i could not believe it but i did. I took real tuning of putting the eyepieces sharp,distance with my glasses to eyepieces was also important and it had to be in the middle of the FOV,further on the positioning of my glasses (double vision) was by far the most important ....

They are very close, but i catched them quite a few times.it as tricky and i verified it to be sure with the

 120 mm...the star position was correct!

A crazy idea. if i would let make eyeglasses that ONLY corrected my astigmatisme, would this be worthwhile...??? instead of fiddling with double vision eyeglasses that never give a nice wide sharp FOV....has anyone had this idea,

 

I looked at the moon too. It has been a while in those binos. Quite impressive! a yellow green small rim off axis CA...not a big deal actually...


Edited by F.Meiresonne, 15 February 2016 - 03:19 PM.

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#15 Rich V.

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Posted 15 February 2016 - 03:39 PM

A crazy idea. if i would let make eyeglasses that ONLY corrected my astigmatisme, would this be worthwhile...??? instead of fiddling with double vision eyeglasses that never give a nice wide sharp FOV....has anyone had this idea,

 

I think that would be a great idea, Freddy!   :D

 

You still may need "readers" for your presbyopia so you can read charts, though.  

 

Rich



#16 F.Meiresonne

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Posted 15 February 2016 - 04:49 PM

 

A crazy idea. if i would let make eyeglasses that ONLY corrected my astigmatisme, would this be worthwhile...??? instead of fiddling with double vision eyeglasses that never give a nice wide sharp FOV....has anyone had this idea,

 

I think that would be a great idea, Freddy!   :D

 

You still may need "readers" for your presbyopia so you can read charts, though.  

 

Rich

 

yes of course, the astigmatisme glasses could be of service for viewing only , nothing else...



#17 Mad Matt

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Posted 15 February 2016 - 08:38 PM

 

I saw it too...i could not believe it but i did. I took real tuning of putting the eyepieces sharp,distance with my glasses to eyepieces was also important and it had to be in the middle of the FOV,further on the positioning of my glasses (double vision) was by far the most important ....

They are very close, but i catched them quite a few times.it as tricky and i verified it to be sure with the

 120 mm...the star position was correct!

A crazy idea. if i would let make eyeglasses that ONLY corrected my astigmatisme, would this be worthwhile...??? instead of fiddling with double vision eyeglasses that never give a nice wide sharp FOV....has anyone had this idea,

 

I looked at the moon too. It has been a while in those binos. Quite impressive! a yellow green small rim off axis CA...not a big deal actually...

 

 

Excellent!!!

 

It sounds like your glasses are "varifocaal"? If so then you really need to get "simpler" glasses that correct only for your astigmatism. For me getting the eye placement correct is hard enough without glasses. I imagine getting the bino's position correctly in addition to the glasses would be a daunting exercise :-)

 

I have a slight Myopia (+1) so I need reading glasses to read dim charts. I just hang them from a strap around my neck. I am currently looking at converting a pair of these to red led's: http://www.amazon.de...dp/B00D6N5954/ 



#18 Matt Mofidi

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Posted 15 February 2016 - 10:12 PM

Brave!!!  And a well worth it mod. 

 

Here is the BA8 15x70 modified with WO 20mm SWAN 72deg AFOV eyepieces. The results blow away most binos in this power/aperture. 

 

Well corrected to 90% from center, and CA is minimal and only seen at outer 80% with bright objects. 

 

Usable eye relief is about 20mm. 

 

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#19 Prescott702

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Posted 15 February 2016 - 11:41 PM

Matt, on the 110 ba8 what will be the resulting mags with those wo ... if you are able to estimate it, sure.

#20 Matt Mofidi

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Posted 16 February 2016 - 12:20 AM

Assuming the focal length of the original eyepiece is 19mm, then Focal Length Bino = 19mm x 28 = 532mm.  Then with 20mm WO's you get 26.6x. 

 

If some one knows the actual focal length then we can have a more accurate estimate. 

 

The good thing about the WO's is that the eyepiece body is narrow enough that with some good tape such as Kapton, they can be threaded in and get close to the prism to reach focus. 

 

For the 70mm version, I have tried to get the 17.3 Delos to work but need to cut the eyepiece holder tubes in hope to reach focus. If I can get this to work then it would blow away even the 18x70 Astrolux, and would be able to change eyepieces at will....need a few days off to get this done. 


Edited by Matt Mofidi, 16 February 2016 - 12:20 AM.


#21 Mad Matt

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Posted 16 February 2016 - 03:15 AM

That is pretty awesome Matt. Can you post some more pictures? I did not think normal eyepieces would com into focus. Hmm... maybe I should try this with the 21mm Pentax XL's I don't use any more.


Edited by Mad Matt, 16 February 2016 - 03:18 AM.


#22 Matt Mofidi

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Posted 16 February 2016 - 03:29 AM

I tried it with the 10mm XW's and it was still "miles" away from reaching focus as the body of the eyepiece is so big.  The bino eyepiece housing has to be modified to get the big eye lens eyepieces in there. 

 

So far the WO 20's have been plug and play.  The WO 15mm reach focus too, but the eyerelief and the correction is not as good.  


Edited by Matt Mofidi, 16 February 2016 - 03:30 AM.


#23 Matt Mofidi

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Posted 16 February 2016 - 03:44 AM

Here is another angle. 

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#24 Mad Matt

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Posted 16 February 2016 - 04:30 AM

Cool! Now I see how you did that. Is there vignetting at the edge noticeable?  The SWAN's should have a 25mm field stop which is slightly larger then the rear prism opening (23mm if I recall correctly).



#25 GlennLeDrew

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Posted 16 February 2016 - 05:21 AM

I think these quality binos use prisms having a 24.5mm (0.965") clear aperture.

 

Binos having clearly slimmer prism housings have smaller prisms with apertures of 21-22mm.

 

I adapted 15mm f.l. eyepieces having 85 deg. AFoVs and 24.5mm diameter field stops to a Celestron 25X100. That bino's rear prism aperture is a small ~17mm (!!), in spite of it being of the "22mm" size, this done to improve baffling against stray light. (Thee first prism is stepped, having the entrant side a wider 24.5mm. You can see this in my Gallery; link in signature.)

 

One might think that a 24.5mm field stop behind a 17mm prism aperture would result in *awful* vignetting. Not so! I could not really say I could see it. The distance between prism aperture and field stop is perhaps a bit longer than in many other binos, and this combined with the fast objective makes the edge shadowing reasonably diffuse, thus rendering it less obtrusive.

 

The former 25X100 with 2.4 degree FOV became a 26X100 with a 3.5 degree FOV. 


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