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Clear aperture 20x80? Is there any? If not, maybe true aperture 15x70...

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#1 SouthernSkiesCro

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Posted 19 July 2021 - 04:29 AM

Hello,

 

I am looking for 20x80 binos to compliment my airline portable 8" F5 dobsonian as an ultra compact set up while travelling.

 

I was looking into Opticron Oregon 20x80 as I read in the reviews it gives a brighter image then the chinese models, however its out of stock in the EU until september 1st. And new regualtions mean taxation when ordering from UK.

 

I was wondering if anyone had performed the light test and found out whether there is a single 20x80 that is true 80mm aperture, in the lower to middle price range?

 

 

Alternatively I was looking at a better 15x70 model. If 15x70 is clear aperture then the difference in light grasp isnt that much between it and the average 20x80 model, and I honestly prefer the sparkly look of a larger exit pupil. 4mm is large enough for me, but still I will rather pick up a true aperture 15x70 then obstructed 20x80.  Oberwerk ultra 15x70 comes to mind, but price is a factor...

 

 

So...has anyone made a measurement? ☺

 

Regards,

Adrian



#2 Corcaroli78

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Posted 19 July 2021 - 06:38 AM

Hello,

 

I am looking for 20x80 binos to compliment my airline portable 8" F5 dobsonian as an ultra compact set up while travelling.

 

I was looking into Opticron Oregon 20x80 as I read in the reviews it gives a brighter image then the chinese models, however its out of stock in the EU until september 1st. And new regualtions mean taxation when ordering from UK.

 

I was wondering if anyone had performed the light test and found out whether there is a single 20x80 that is true 80mm aperture, in the lower to middle price range?

 

 

Alternatively I was looking at a better 15x70 model. If 15x70 is clear aperture then the difference in light grasp isnt that much between it and the average 20x80 model, and I honestly prefer the sparkly look of a larger exit pupil. 4mm is large enough for me, but still I will rather pick up a true aperture 15x70 then obstructed 20x80.  Oberwerk ultra 15x70 comes to mind, but price is a factor...

 

 

So...has anyone made a measurement? ☺

 

Regards,

Adrian

Hi Adrian, 

 

Helios Stellar II 15x70 are effective 70 mm aperture and very affordable. I have them and i am really happy with the quality and the views

 

Carlos



#3 Rich V.

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Posted 19 July 2021 - 08:57 AM

I'd expect the Opticron Oregon 80mm, being a Chinese LW bino itself, to be around 72-75mm effective aperture.  That's typical of LW type binos.  You'd have to move up to something like the Helios LightQuest to get into the sturdier, full aperture binos.

 

Regarding full aperture 70mm models,  any vendor's version of the "mil spec" KUO BA8 (Helios Apollo), MS or MS ED (Helios LightQuest, APM) are full aperture and "shockproof" unlike LWs.  Carlos says the Helios Stellar are full aperture as well; perhaps a good in-between choice if on a budget.

 

Rich


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#4 TheUser

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Posted 19 July 2021 - 09:16 AM

I think any model of 20x80 will be having true aperture



#5 Rich V.

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Posted 19 July 2021 - 09:52 AM

I think any model of 20x80 will be having true aperture

This is not the case, even if the objective lens measures 80mm.

#6 ihf

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Posted 19 July 2021 - 06:10 PM

How will you hold mount your 20x80? I suspect you may not have enough capacity to bring a tall tripod and video head?


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#7 sevenofnine

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Posted 19 July 2021 - 06:38 PM

Before you spend any money on large straight through binoculars, first and foremost consider how you are going to mount them to view the night sky. I own them both and that's much more important than any concerns about "clear aperture." Best of luck to you and your decisions! waytogo.gif


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#8 SouthernSkiesCro

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Posted 20 July 2021 - 02:51 AM

I definitely plan on mounting them eventually.

I already have 16x50 so i am not sureif there will be a big difference between them and 15x70.

20x80 seems like a natural progression.

As far as magnification goes, yes, 16x is for me just about the limit to be able t see sth when propped up etc. So 20x definitely needs a steady mount.

I would be content with sth like 12x60 in addition to the 8 inch, but the issue is, a lot of times i prefer the bino viewing to the telescope and find myself draging only bino to the beach.

Hence i want sth more substantial to be able to see more.

I agree that the mount should be a priority.




But i just wanted to see if there are true aperture 80s,because if there are not and yet there are true aperture 70s,then it makes sense in my case due to my attraction to larger exit pupils to pick up a true aperture 15x70 as the difference between 70 and 75mm is marginal at best.

#9 Cestus

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Posted 20 July 2021 - 09:40 AM

I have both. The 20x goes deeper and larger. That's to be expected. However, the fov is smaller and that too is expected. I will say the 20x is rather heavy and is as large as I am likely to go.



#10 sevenofnine

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Posted 20 July 2021 - 11:13 AM

Even the LW (light weight) 20x80's sold by Oberwerk and others will require mounting to use them. They are not hand holdable to view the night sky. Think of straight through binoculars in this class as a package deal. 20x80's + mount + tripod = a usable combination. The more robustly constructed Deluxe version is 7 lbs. and needs a heavy duty video tripod to do the job. That is at least 10 lbs and that's if you go the lightweight carbon fiber route. 

 

Just to prove a point, try this. Tonight, go outside and look straight up. Now hold that position as long as you can. That's the position that straight though big binoculars put your head and neck in. Plus, that's the best case scenario. Even the P-mount has it's challenges. Finally, the 15x70 option is only a little better in this regard. If you really want something that is hand holdable, the only good option IMO are image stabilized binoculars. Best of luck to you and your decisions! watching.gif



#11 ihf

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Posted 20 July 2021 - 02:35 PM

For easy&compact travel Canon IS 15/18x50.

#12 SouthernSkiesCro

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Posted 20 July 2021 - 03:37 PM

Well my 8 inch dob will be way lighter than the aforementioned set up. Hmmmm.

The issue is not the weight of the binos, its trying to hold them steady.

Like i said i have 16x50s and this is about he usable limit for magnification for hand held, and even with this the mounted view is so much superior.


As much as i would like 20x80, it seems like 15x70s are the logical choice, at least they are basically half the weight of the 80s so its a good thing for travel as complimentary to the dob.

But i am not going smaller than 15x70.



I have to sleep over this and then decide.

#13 ihf

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Posted 21 July 2021 - 09:14 AM

I understand you are stuck on aperture. At the same time you do seem to value traveling. If you are willing to take a sleeping pad and lie on the ground, or sit on a bench or comfortable hiking chair, you can steady a 15x70 enough to very briefly enjoy it. Otherwise a tall tripod (say an Innorel RT85C) will allow mounting, but easily add 3kg to the trip. That tripod will be able to handle the 20x80 too, but it gets more dicey with an 25x100. I do put a premium on portability and traveling. I can tell you the 15x70 will show a little richer sky, but the image stabilization of the Canon 15x50 will show you essentially the same stars with a darker background. At the same time it is way more portable and easier to handle than a 15x70. The Canon 18x50 will go deeper, but will again require careful sitting. I'd get the Canon and use the weight/volume saved of not taking the tripod to upgrade the Dobsonian from 8 to 10 inches. (By the way, which model travel Dobsonian do you use? Is it commercially available? I am somewhat interested in a compact setup.)


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