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How important is ED glass?

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#1 LasVegasMikey

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Posted 25 July 2019 - 11:05 PM

I’m in the initial phase of research for my first pair of astronomy binoculars. I believe that I’ve got a fair understanding of the basics (magnification, objective lens size, FOV, eye relief, and exit pupil). The part that I’m struggling with is the ED glass - some models have it and others don’t. 

 

My budget is $200 but I might be able to stretch to $250. I’m trying to sort out the compromises I’ll need to make to hit my price point but I don’t know if having ED should be a priority or not.

 

Can someone shed some light and point me in the right direction?

Thanks in advance,

Mike



#2 Cajundaddy

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Posted 25 July 2019 - 11:20 PM

ED glass brings the visible light spectrum into tighter focus than Achro so it tends to be sharper to the edge and has less chromatic aberration, especially at higher mags.  Whether it is important to you depends on your tolerance to CA.  A good quality 8x42 with standard glass displays very little CA to my eyes and none of my binos have it.  I do appreciate ED glass on scopes especially as the mag rises above 60x or so.

 

Try both under full daylight and see what you think. 


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#3 sg6

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Posted 26 July 2019 - 02:35 AM

I would like to know what you mean or expect as "astronomy binoculars".

To me they are the large items that are on a pier or their own tripod, are around 80mm diameter and have 45 degree eyepieces.

Vixen-AB

 

Someone putting "Astronomy binoculars" on a set of 15x70 do not, to me anyway, make them astronomy binoculars.

 

I have found that even 8x ones will have Jupiter bouncing around, 10x and handheld they are not stable. In effect at 10x and certainly above will need a suitable tripod. And putting binoculars on a tripod would seem to remove the purpose of having binoculars. You cannot stand somewhere and freely and easily look around the sky.

 

You are likely to find also that say they are 15x70, then the image will be "dimmed". Caused by the simple addition of an aperture ring/baffle internally that reduces the effective diameter but reduces aberrations. So yes a 70mm objective but operates as 60mm.

 

I like binoculars and have sevral pairs, but understand what you are buying and binoculars are more then just 2 largish numbers.


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#4 Jon Isaacs

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Posted 26 July 2019 - 05:28 AM

Astronomy binoculars:

 

I have a pair of 15 x70 Orion Resolux. They operate at full aperature and the eyepiece focus individually. They weigh 5 pounds and only make sense to me for viewing the night sky.

 

ED glass:  for hand held binoulars, for binoculars one can buy for $250, color correction is not a big issue. Some CA might be visible on bright stars but one is not trying to resolve festoons on Jupiter.. 

 

Jon


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#5 Mark9473

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Posted 26 July 2019 - 05:37 AM

Roof prism binoculars tend to show more CA than porros, so they benefit more from ED glass. For a porro up to 15x or so, I wouldn't actively look for an ED model.
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#6 Diego

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Posted 26 July 2019 - 05:38 AM

I've always asked myself the same question. I completely understand the ED glass principle, but for low power binoculars does it really make much of a difference?
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#7 Riccardo_italy

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Posted 26 July 2019 - 07:34 AM

I tried the Celestron Skymaster PRO 15x70. Achro. Daytime use: too much color (I returned them). However for astronomy they were OK.

 

If you want a dual use binocular, get the ED glass. For astronomy only and low magnification, achro is OK.

 

At the end, I ended up purchasing an ED spotting scope for nature&sky (Celestron Regal 65).


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#8 LasVegasMikey

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Posted 26 July 2019 - 07:58 AM

I would like to know what you mean or expect as "astronomy binoculars".

To me they are the large items that are on a pier or their own tripod, are around 80mm diameter and have 45 degree eyepieces.

Vixen-AB

 

Someone putting "Astronomy binoculars" on a set of 15x70 do not, to me anyway, make them astronomy binoculars.

 

I have found that even 8x ones will have Jupiter bouncing around, 10x and handheld they are not stable. In effect at 10x and certainly above will need a suitable tripod. And putting binoculars on a tripod would seem to remove the purpose of having binoculars. You cannot stand somewhere and freely and easily look around the sky.

 

You are likely to find also that say they are 15x70, then the image will be "dimmed". Caused by the simple addition of an aperture ring/baffle internally that reduces the effective diameter but reduces aberrations. So yes a 70mm objective but operates as 60mm.

 

I like binoculars and have sevral pairs, but understand what you are buying and binoculars are more then just 2 largish numbers.

I didn’t know how much of the backstory would be relevant so I opted to not bore you guys with all the nitty gritty details; 

 

I’ve got a fairly pronounced hand tremor so anything I will be doing needs to be tripod mounted. I’m probably just going to be using my binoculars for a more portable option to my Nexstar 6SE telescope. Although I can’t rule out terrestrial viewing, I don’t anticipate using them for anything other than stargazing while away from home. I was originally intrigued by the idea of a pair of 10x70’s or 15x70’s but the collimating issues may have scarred me away from anything with a larger objective. (I haven’t seen reports of widespread collimating problems on smaller objectives so I assumed it was only an issue with larger models. Also, my tremor has me a little gun-shy about getting something that requires fine adjustments on a regular basis).

 

So, bottom line is that I’m leaning towards a pair of 10x50’s that can be mounted on a tripod. From the responses here, it appears that ED is nice but not critical in this size.

 

i sincerely appreciate your feedback. Thanks to everyone who took the time to help me get started.


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#9 Binojunky

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Posted 26 July 2019 - 09:35 AM

Like most things its used as an excuse to hook the buyer into making a purchase, I have owned over the years a ton of binoculars and some with the so called ED glass have been a let down, some non ED instruments have out performed them. First pair for astronomy, Bushnell Legacy , Nikon Action Extreme in the 10x50 size of if weight is an issue then  8x40(42), if you prefer a roof prism design, then the Vortex Diamondback 8x42 is a good buy.

              Be aware that most binoculars at the price level you want to pay will not be perfect but everything in life is a compromise, D


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#10 vdog

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Posted 26 July 2019 - 11:14 AM

The Nikon Action Extremes are great 10x50s for astronomy use.   These would be well within your budget and would leave you money to spend on a good tripod.  About the only time I notice any CA is when I'm looking at the moon, but it doesn't bother me.

 

Speaking of tripods, try to budget at least 100-150.00 to get a good, sturdy, tall tripod.  Sturdy because, while most 10x50s are pretty light, you may want to get bigger (and heavier) binos later.  Tall because you'll need the height for overhead viewing.


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#11 edwincjones

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Posted 27 July 2019 - 07:39 AM

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

 

So, bottom line is that I’m leaning towards a pair of 10x50’s that can be mounted on a tripod. From the responses here, it appears that ED is nice but not critical in this size.

 

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

 

 

waytogo.gif  a reasonable conclusion  waytogo.gif

 

edj


Edited by edwincjones, 27 July 2019 - 07:44 AM.

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#12 Foss

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Posted 27 July 2019 - 08:53 AM

You'll probably want to limit your search to binoculars with tripod sockets. :-)


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#13 Blind as an Eagle

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Posted 03 August 2019 - 04:22 AM

Expect to investigate paralellogram mountings, once you've jammed your neck muscles viewing anything above 45 degrees elevation.
I wonder when the day will arrive that sees a transition to photonics-based hardware for astronomical viewing. The large Navies of the modern era have adopted this concept, in lieu of optical glass based systems (and they have access to the very best quality glass based optics) for submarine periscope usage.  The possibilities of employing DSP in this scheme would be vast and versatile.
I have used my Fujnoni 10x, 50mm FMTR-SX binocular with a tripod and have had very impressive views of Jupiter etc. when it it sits low (under 50 or degrees elevation) with dawn approaching. Viewing above that elevation angle was typically physically problematic.
It's OK, going to more sophisticated mounting schemes is just a part of the normal progression in one's astro binoscopy capibilities.

 

https://www.janes.co...ter_picture.pdf


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#14 hallelujah

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Posted 03 August 2019 - 07:04 AM

https://www.cloudyni...-in-binoculars/

 

Stan


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