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Ultra Light Binoculars For Astronomy

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#1 saemark30

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Posted 30 May 2020 - 02:05 AM

Anyone else using small 8x20 and 10x25 high end binoculars?

I am talking about near perfect Leitz and Zeiss ones not $20 discount ones.

They even have brighter image than recommended 7x35 (and 7x50) Carl Wetzlar Navigator binoculars in Consumer Reports.  

Let me know what Messier objects you have seen in them.

It would be interesting if one can see/detect many galaxies.



#2 SMark

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Posted 30 May 2020 - 02:14 AM

One thing I struggle with when using small binoculars for astronomy is not being able to hold them steady enough. For   whatever reason, larger, heavier binoculars will often offer me a more stable image.


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#3 db2005

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Posted 30 May 2020 - 02:37 AM

I sometimes use my SG Vixen 6.5x32 binoculars as they are fairly light, quite easy to hold steady and have good optics. Can't claim much in terms of Messiers, but scanning the Milky Way and looking at open clusters is very nice.



#4 KennyJ

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Posted 30 May 2020 - 03:01 AM

Having briefly passed a phase around 15 years ago of trying Swarovski 8x20 pocket compact binoculars for night sky viewing, my overall impressions were that while the stars themselves did appear pin-point, a combination of the physical awkwardness and unsteadiness associated with diminuitive dimensions, the exit-pupils being only 2.5mm, the AFOV only around 50 degrees and the eye-relief too short for me, led these to be amongst my least favourite of all binoculars I've ever tried for astro use.

 

Kenny


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#5 publin

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Posted 30 May 2020 - 03:26 AM

 product.  high   end   compact  size   bino's   as  this  above  mention   is mainly   good    for   terrestrial    view    or   birding   or   best for spy....    not   for  astronomy.    [    galaxies / messiers/ our   solar  planets]  due  to  there   small  exit  pupil  and  small  objective  lens   and  narrow   f.o.v    despite  the  top quality   that  is  the   tripods   made for   medium/  big  astronomic bino   use for!    as  you   will   not   take  to  theater    astrobino....!   or   watching   birds   with   theater   bino.....!     each   view   target  has  the  proper  instrument.  


Edited by publin, 30 May 2020 - 03:40 AM.

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#6 Mark9473

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Posted 30 May 2020 - 04:20 AM

Anyone else using small 8x20 and 10x25 high end binoculars?

I am talking about near perfect Leitz and Zeiss ones not $20 discount ones.

They even have brighter image than recommended 7x35 (and 7x50) Carl Wetzlar Navigator binoculars in Consumer Reports.  

In the daytime your eye pupils are small and for most sizes of binoculars the difference in brightness is then due to the light transmission of the instrument (this is what Consumer Reports talk about); it is only when the binocular's exit pupil becomes smaller than the eye pupil that the exit pupil becomes an additional factor.

 

At night your eye pupils are large, larger than many binocular's exit pupil, and then the brightness difference between binoculars is primarily due to the area of the exit pupil and the light transmission becomes only a minor secondary factor.

 

What this means in practice for night viewing:

8x20 have 2.5 mm exit pupil

7x35 have 5 mm exit pupil, that is 4x the area so 4x more light so 4x brighter - instrumental light transmission differences of say 20% are insignificant compared to that.

7x50 have 7.1 mm exit pupil i.e. 8x brighter than the 8x20 and 2x brighter than the 7x35 on condition that your eye pupil is at least 7.1mm.

 

I have a Leica 8x20 and while it certainly has its uses, astronomy is not one of them. It is just extremely dim at night. Even in the daytime it is not super bright because my eye pupil are often larger than 2.5mm.


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#7 Corcaroli78

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Posted 30 May 2020 - 04:22 AM

For some time, i used as a travel companion a Zeiss 8x20B with the intention to have quick views at night, but soon i realized that it is not optimal. Certainly a small bino is better than no bino, but I decided that my very minimum for astronomy is an 8x30.  At least in my case, the 20 mm aperture is still small to detect and enjoy some messiers, unless i am going to very dark locations, and that is not my case. Even the Pleiades do not look so filled with stars in the 8x20 as in the 8x30.

 

Carlos


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#8 Grimnir

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Posted 30 May 2020 - 04:37 AM

Having briefly passed a phase around 15 years ago of trying Swarovski 8x20 pocket compact binoculars for night sky viewing, my overall impressions were that while the stars themselves did appear pin-point, a combination of the physical awkwardness and unsteadiness associated with diminuitive dimensions, the exit-pupils being only 2.5mm, the AFOV only around 50 degrees and the eye-relief too short for me, led these to be amongst my least favourite of all binoculars I've ever tried for astro use.

 

Kenny

 

+1. Good for lightweight hiking but not much else IMO.

 

Graham


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#9 Tony Flanders

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Posted 30 May 2020 - 01:09 PM

Anyone else using small 8x20 and 10x25 high end binoculars?
I am talking about near perfect Leitz and Zeiss ones not $20 discount ones.
They even have brighter image than recommended 7x35 (and 7x50) Carl Wetzlar Navigator binoculars in Consumer Reports.


So much for Consumer Reports! The images of 8x20s may be prettier than some 7x35s, or clearer, or sharper, but no way are they going to brighter in any sense useful to astronomers. Physics prohibits it.

For observing galaxies, I doubt there's going to be a huge difference in that magnification/aperture range between $1,000 binoculars and $20 binoculars of identical specifications.

I rarely observe galaxies with my smaller instruments, but next new-Moon cycle I'm planning to see which Messier galaxies are visible through my 6.5x21 Papilios. I'll post my results in this group. So far the only galaxies I've viewed with them were M31, M110, and M33. I failed to see M32 as non-stellar, presumably because of inadequate magnification.

I predict that the Papilios will pull in M81 pretty easily, likely also M82, will struggle but succeed with M66, and perhaps a few more of the biggest and brightest Messier galaxies.

Edited by Tony Flanders, 30 May 2020 - 01:11 PM.

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#10 j.gardavsky

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Posted 30 May 2020 - 03:39 PM

I used to have 2 pairs of Leitz 8x20, parted with them, and tested the 10x25 ZEISS and did not buy.

 

JG


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#11 saemark30

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Posted 31 May 2020 - 02:33 PM

This is a minimalist experience not optimal one so don't misunderstand the purpose of thread.

Same as using Zeiss 63mm Telementor VS 8 to 16" dob!

 

But this is minimalist at its finest and the pinpoint stars and ultra-high contrast leads me to an ethereal (light, heavenly) experience. M45 are blue jewels of pin-**** points in Zeiss 10x25. They can be had used from $250 or so.

I will try for M101 next dark moon.

 

There is a huge difference between say Bushnell compact 8x20 discount binoculars and anything worth owning.

Those discount ones are poor, cannot focus to a sharp point, poor coatings, everything looks like in a fog.

 

Consider a compact can be placed in a pocket and I am able to travel by car to Bortle 4,3,2 skies.

The skies are dark enough to do naked eye astronomy!

 

BIg binocs are going to show all the Messiers But!

I will not carry big binocs around as they are prone to be knocked out of collimation. Even 70mm ones.

 

I have 7x35 Tasco binocs but they are out of collimation and images not that different from the discount Bushnell from above.

 

Carl Wetzlar sounds like a fancy brand but this is intentionally misleading.

Carl from Carl Zeiss and Wetzlar from a German city cause one to think good quality, expensive brand but this is psychological trick only. The prisms are not coated and perhaps only outer lens surfaces have low quality coatings.

 

Even the bargain Bushnell Ensign were better/brighter.

 

If you find them hard to hold steadily there are Canon 10x30 IS binocs and people love those. I believe Gary Seronik has tested those and bigger 15x45 IS ones so there is something about 3mm eye pupil that is right for astronomy.


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#12 Ant1

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Posted 31 May 2020 - 04:38 PM

Hi,

 

After much testing I have come to the conclusion than the minimum exit pupil I can live with is around 4mm.

All the 8x20, let alone 10x20, regardless of quality and price, are just not useable for me.

Lightweight bins ? sure! I use 6x24 and 8x30 the most.

I have a pair of these 6x24. They're available new for a very reasonable cost, weigh 350g, and once the reticle has been removed  collimation fixed, they are wide and enjoyable under the summer night sky.

 

Regards,

Ant1

20200531-201411.jpg


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#13 saemark30

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Posted 31 May 2020 - 08:38 PM

 6x bino would be very useful for studying constellations and finding objects. They show objects as they are rather than drawn star charts or low time exposure images that show too much detail.



#14 saemark30

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Posted 01 June 2020 - 10:56 AM

One other surprisingly bright compact I have used is the Bushnell 7x26 Custom. These are good  as a preview for telescope use, and fortunately are quite common and so sell for much less money. They have porros so are bigger than the ultra compacts but still take little space in the glove compartment or large pocket.



#15 dries1

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Posted 01 June 2020 - 12:34 PM

If, and I say If,  one is comfortable with 10X handheld,  try a Monarch HG Nikon 10X42 it has almost 7 degree FOV and it is very light. I would not even try to view the night sky with a 8X20 or 10X25.

 

Andy W.


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#16 Tony Flanders

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Posted 02 June 2020 - 04:44 AM

 6x bino would be very useful for studying constellations and finding objects. They show objects as they are rather than drawn star charts or low time exposure images that show too much detail.

Less useful than you might imagine. Most 6x binoculars do not have especially wide true fields of view. Old-fashioned ultrawide 7x35 binoculars do far better for this purpose. But even they can't fit whole constellations in the field of view, except for the very smallest. For that, you need 2X Galileans.


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#17 edwincjones

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Posted 02 June 2020 - 05:07 AM

one uses what one has

we start with our eyes (1x1-7mm) and expand

8-10x is better, as is 20-25mms

this is a start 

 

edj


Edited by edwincjones, 02 June 2020 - 05:08 AM.

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#18 saemark30

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Posted 04 June 2020 - 08:43 AM

Compared Zeiss 10x25Bto Japanese 10x70s. Looked at Moon and Lyra area.

Zeiss was much sharper. Moon edge was crisp and stars were pinpoints. Even bright stars and the faint ones were extremely small.

 

Now the 10x70 was brighter of course but did not overwhelm the smaller instrument. Stars were blobs and more irregularly shaped. So the light was not as well focused to a tiny point but spread over like a crude dob.

 

Big difference in weight. Which one would you prefer hanging around your neck?

This time, I will take the much smaller and more precise instrument the Zeiss 10x25B.


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#19 paulsky

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Posted 04 June 2020 - 02:05 PM

Hi,

 

I'm glad to hear your comments ...
Something similar happened to me a long time ago, in this case I casually compared some tiny Leica 8x20 with others Porro prism of 10x50, undoubtedly the latter, giant compared to the tiny, showed greater luminosity ... but I think, in my humble opinion, that it was the only thing that was ahead of the little Leica ..., in contrast, sharpness, cleanliness, purity ... of image, the Leica won by a landslide ... okay, this did not go so deep, but the sky was incomparably more "aesthetic" and beautiful through the "canijo" Leica.
Thank you
Paul


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#20 Rich V.

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Posted 04 June 2020 - 02:21 PM

Compared Zeiss 10x25Bto Japanese 10x70s. Looked at Moon and Lyra area.

Zeiss was much sharper. Moon edge was crisp and stars were pinpoints. Even bright stars and the faint ones were extremely small.

 

Now the 10x70 was brighter of course but did not overwhelm the smaller instrument. Stars were blobs and more irregularly shaped. So the light was not as well focused to a tiny point but spread over like a crude dob.

 

Big difference in weight. Which one would you prefer hanging around your neck?

This time, I will take the much smaller and more precise instrument the Zeiss 10x25B.

Your observation makes sense to me.  I'd expect the difference you see between a 2.5mm and a 7mm exit pupil to lie more in your eyes than in the binoculars themselves, though.  A 2.5mm exit pupil passes through our eye's central "sweet spot" portion of the the lens while the 7mm EP encompasses the maximum area of the lens including the more aberrated outer areas, showing off the inherent flaws and reducing sharpness.

 

Rich


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#21 BGazing

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Posted 04 June 2020 - 02:22 PM

I'd rather have a 30mm IS binocular than a 50mm non-IS one, light grasp ain't all.


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#22 publin

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Posted 09 June 2020 - 09:44 AM

Compared Zeiss 10x25Bto Japanese 10x70s. Looked at Moon and Lyra area.

Zeiss was much sharper. Moon edge was crisp and stars were pinpoints. Even bright stars and the faint ones were extremely small.

 

Now the 10x70 was brighter of course but did not overwhelm the smaller instrument. Stars were blobs and more irregularly shaped. So the light was not as well focused to a tiny point but spread over like a crude dob.

 

Big difference in weight. Which one would you prefer hanging around your neck?

This time, I will take the much smaller and more precise instrument the Zeiss 10x25B.

zeiss   quality   can  beat   most   of    " big  aparture"     bino's   that  some  members  mention  the  importent  of  this.   the  lens  light transmitting  of zeiss  make      the   diffrent   between  2.5  exit  pupil   of  zeiss   and   5  - 7   exit  pupil  of   other   brunds.  that is  why   the  cost  of   zeiss   bino's  is  10x  more  then   others!   enjoy  the   10x25   even  for   night  sky  sometimes.



#23 Grimnir

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Posted 09 June 2020 - 10:02 AM

I'd rather have a 30mm IS binocular than a 50mm non-IS one, light grasp ain't all.

 

My Fuji 10x50 FMT-SX2 is a better instrument for astronomy than my Canon 10x30 IS.

 

Graham


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#24 BGazing

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Posted 09 June 2020 - 11:50 AM

My Fuji 10x50 FMT-SX2 is a better instrument for astronomy than my Canon 10x30 IS.

 

Graham

I know the limitations of IS, but I have trouble holding non-IS binoculars steady enough for stargazing. In daytime, they are fine (the views from my friend's Noctivid are nothing short of spectacular). But in the evening, try as I might, the stars are dancing around. Perhaps 12x36 IS III for me one day...



#25 Brent

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Posted 09 June 2020 - 09:02 PM

This is a minimalist experience not optimal one so don't misunderstand the purpose of thread.

Same as using Zeiss 63mm Telementor VS 8 to 16" dob!

I get it.  Using small instruments gives a different aesthetic that sometimes is preferable to that of larger instruments--to me, at least (and to a few others, it seems).

 

I used to employ a pair of Leica Trinovid 10X25 BCA for astronomy quite often.  Depending on ambient light pollution, M81 and 82 are within easy reach of a binocular this size.  I could see them while hiding within the shadows cast by the security lights around our apartment complex in Durham, NC.  In the deserts of Utah, with the binoculars mounted on a tripod, the same pair of galaxies were standouts.  

 

One night it was a lot of fun to find and split 61 Cygni, and also to observe the tiny lunar crater Bessel named for Friedrich Wilhelm Bessel who first calculated the distance of 61 Cygni.  (Full disclosure: it may not have been on the same night--that was a long time ago.  It was at least around the same time.)

 

The point is that small binoculars can be a lot of fun, and it can be rewarding to see how far one can push one's powers of observation and the limits of the instrument.  That is part of the fun.

 

Still, they are difficult for me to hand-hold and keep steady.  I prefer my 8X32s--but now we're talking big binoculars.  cool.gif

 

Brent


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