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Low mag big aperture galilean binoculars?

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#1 has530

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Posted 15 May 2021 - 02:06 AM

I have heard a lot of good things about these low mag Galilean binoculars. My question is, what's the hype about? With configurations like 2x54, you end up with a massive 27mm exit pupil which obviously no human eye can match. If you can dilate to a respective 7mm, aren't you essentially stopping down to aperture of 14mm? Does this really show you significantly more than the naked eye that it is worth spending a the money on them and losing half your FOV? 



#2 PEterW

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Posted 15 May 2021 - 02:56 AM

Yes, but the optical rules are different. You do get your 7mm pupil filled, the aperture of the binoculars is needed to give you a wide field of view. Also the closer you can get your eyes to th lenses the wider the field. They provide a welcome number of extra stars under my urban skies.

Peter

#3 Redbetter

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Posted 15 May 2021 - 04:39 AM

You don't lose "half your FOV."  That wouldn't be the case even with a Keplerian vs. Galilean design.  Instead you would lose image brightness if the aperture was stopped down by the eye's pupil.  I can put a 55 Plossl into an f/6 scope and still get the full field of view, it is just operating as a smaller aperture in terms of brightness, limited by my pupil.  This is true in daylight as well, when my pupil is much smaller.  

 

Galilean binocs don't operate the same way as standard Keplerian designs.  The aperture is there for field of view in this case.  And I don't find my 2.3x40's FOV sensitive to eye position, or to my eye's pupil (e.g. comparing daylight to night time for the latter.)  So this is more a matter of what a person is after. 

 

Having something that can provide 20 or even 30 plus degrees of true field with a small amount of magnification is a great increment up from naked eye, and spacious compared to standard binocular or finder fields. They fill a gap between standard binoculars and naked eye.  The combination of a 2x greater scale, plus being able to see 1.5x mag deeper (for a 2x pair) or 2.3x and 1.8 mag (for my 2.3x pair) shows what is just beyond the eyes' ability in a given conditions.  I might not be sure if I am resolving something naked eye, but my 2.3x binocs make it clear if something is real, imagined, or being confused with something else of similar brightness very near. 

 

The usefulness depends on the observer, and what a person is seeking from them.  As an aid to naked eye I find my 2.3's (especially with nebula filters) hard to beat. They are far more useful for star hopping.   But they won't show nearly as much as my 10x50's.  In spite of that, I use my 2.3's more frequently than I use my 50mm and 80mm binoculars combined, but I am not big on standard binocular viewing.  After a few minutes with binoculars I am craving the versatility and (most importantly) the relative viewing comfort of a small refractor scope.  


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#4 edwincjones

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Posted 15 May 2021 - 04:56 AM

 

.............

My question is, what's the hype about?

..............

 

I think they are fun, 

to set back and scan the skies

like naked eye but more so

 

edj



#5 Tony Flanders

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Posted 15 May 2021 - 06:38 AM

More than one person has described them as restoring teenage vision to 70-year-old eyes. You can go about one magnitude deeper on stars, making all the main stars of the fainter constellations (like Cancer or Pisces) visible from bright suburban skies, and making sixth-magnitude stars bold and bright under dark skies. All of this with a field of view big enough to take in the entire Big Dipper and more.


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#6 ihf

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Posted 15 May 2021 - 09:09 AM

My dad likes to identify constellations. The 2x54 specifically are wide enough for this. They help his 70 year old eyes and help a bit with light pollution. Strangely a friend of his was interested in them for watching TV! Now I think they dont work too well for people needing glasses for astigmatism, lile myself. So the widest I can use is 5x25 Vision King.



#7 KennyJ

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Posted 15 May 2021 - 10:17 AM

My apologies to Peter and to yourself Mark.

 

Thanks for pointing that out.

 

I will delete my original post, and if you would be kind enough to delete your reply, it would be less confusing for any future readers.

 

Kind regards,

Kenny


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#8 sevenofnine

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Posted 15 May 2021 - 01:06 PM

Others with good vision have said that under light polluted urban skies, they can see the constellations again. In dark skies vision goes much deeper with a very wide angle view. faint.gif


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#9 camvan

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Posted 15 May 2021 - 09:52 PM

I bought a pair of the Vixen 2.1 x 42 Super Wide 4 or 5 years ago and they;ve just sat there unused as their diopter adjustment can't correct enough for me to see out of them and their eye relief is so short, I can't use my glasses.

 

when I would go star watching with my dad, one of my favorite things to do was just sit in a folding chair and stare at the milky way with one of our two astro dogs in my lap while sipping a coffee of hot chocolate we brought with us in a thermos.

 

guess I should put up a WTS ad for them. :p



#10 Tony Flanders

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Posted 16 May 2021 - 05:54 AM

My dad likes to identify constellations. The 2x54 specifically are wide enough for this. They help his 70 year old eyes and help a bit with light pollution. Strangely a friend of his was interested in them for watching TV! Now I think they dont work too well for people needing glasses for astigmatism, lile myself. So the widest I can use is 5x25 Vision King.

I usually wear my glasses while using my Orion 2x50s. It does reduce the field of view significantly, but I can still fit the entire Big Dipper in the field of view.



#11 ihf

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Posted 17 May 2021 - 05:13 PM

I should be able to visit and try them this summer.

#12 richsvt

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Posted 17 May 2021 - 06:57 PM

I have the Orion variant and they are a nice, easy way to get a grand view. These will not tease out DSOs but if you are like me, they can show a lot under brighter skies. Easy to hold and are almost pocketable. I love using these on the shoreline. In daytime, things do seem to pop into more clarity than my tired eyes by themselves.


Edited by richsvt, 17 May 2021 - 07:00 PM.



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