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7x35 binoculars for viewing the stars?

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#1 mv1612

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Posted 07 December 2012 - 09:14 AM

Hello,

I have a 6" dobsonian and now I want to start using binoculars, because I love large fields of view. Then there is my 5 years old daughter who also seems interested in seeing "lots of stars". I will probably buy both small binoculars so that she's able to hold them and also bigger ones on a mount.

I will start with the small ones. Can I use 7x35 binoculars for introducing my daughter to the skies? Will they be reasonably spectacular compared to naked eyes? I don't think there are 7x35 "astronomical binoculars", so I would buy just all purpose binos, is it worth it? Then, they shouldn't be expensive, I wouldn' t go over $70-80 cause maybe I would buy two, so that we can observe simultaneously.

I have also asked this question on another forum, I hope it's not a problem, I just need as many suggestions as possible.

So, can I use a 7x35 binos, to give nice views of the stars?

Thanks, Virgil.

#2 Mark9473

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Posted 07 December 2012 - 09:16 AM

YES to all of your questions!

#3 StarStuff1

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Posted 07 December 2012 - 09:55 AM

7x35s, especially wide angle ones, are excellent for introduction to the starry skies. Flea markets and garage sales are good places to get them cheap. Just be sure to check mechanical functions and alignment before buying.

Lots of good prices on new ones this time of year. I prefer buying "in person" to check them out. What you would pay in sales tax would probably be less than shipping costs unless you got a free shipping deal.

#4 ronharper

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Posted 07 December 2012 - 10:34 AM

These are good, and especially so for children because the eye spacing can be set small.
Yosemite
Between the 6x and 8x I'm not sure. The 8x will show more, but the 6x is easier to use.
Ron

#5 steve@37n83.9w

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Posted 07 December 2012 - 11:33 AM

Like Ron I highly recommend the Yosemite. I purchased two pairs (6x30) for my grandsons about three years ago and the binos are holding up well. I would also consider a used 7x35 as mentioned by some of the other posters. I have purchased many vintage 7x35s on ebay including my 7x35 9.3* Nikon WideField which is one of my better binoculars.

Steve

#6 mv1612

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Posted 07 December 2012 - 12:37 PM

Hi,

Thanks for your opinions, it seems a small 7x35 will be good for starting. I checked B&H for prices, Amazon and other places for reviews and I ended up with the folowing list of contenders :

Bushnell 7x35 Falcon $24.55 595g
Nikon 7x35 Action VII $64.95 715g
Barska 7x35 Focus Free $29.99 567g
Bushnell 7x35 Powerview $45.77 539g
Eagle Optics 7x35 Triumph $69.95 578g
Leupold Yosemite Binoculars BX-1 6x30 $89.79 482g

The prices are mainly from B&H, an excellent store for me not only because they’re good professionals but also because they have very good prices for shipping to Canada.

I was recommended the Nikon which unfortunately is heavy for my girl, and Yosemite, which is on the expensive side for me and only 30mm compared to 35mm the others. Bushnell Falcon is very cheap and has excellent reviews everywhere… The others, I don’t know…

My favorites are the Falcon, because of reviews and price, and the Yosemites, because of your recommandation, reviews and weight (a bit expensive though).

I’m also tempted by Bushnell Powerview which are lighter than the Falcons. I will eliminate the Nikons because they’re heavy.

Please keep sending your suggestions...

Thanks, Virgil.

#7 StarStuff1

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Posted 07 December 2012 - 12:53 PM

Stay away from any fixed focus binocular.

#8 Rich V.

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Posted 07 December 2012 - 12:56 PM

Just about any inexpensive binocular would be better than a "focus free" binocular for astronomy, IMO. Astronomy requires that stars be viewed at the best possible focus; anything less will ruin the experience.

I also think the "InstaFocus" mechanism as used in the Bushnells, while it works, is less precise than a standard center focus binocular that uses a wheel instead.

At least, you'd do yourself a favor by dropping the Barska "focus free" model from your list...

Rich

#9 mv1612

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Posted 07 December 2012 - 01:01 PM

OK, so I eliminate the Barska.

#10 mv1612

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Posted 07 December 2012 - 01:03 PM

Bushnell 7x35 Falcon $24.55 595g
Bushnell 7x35 Powerview $45.77 539g
Eagle Optics 7x35 Triumph $69.95 578g
Leupold Yosemite Binoculars BX-1 6x30 $89.79 482g

#11 Rich V.

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Posted 07 December 2012 - 01:38 PM

I don't see the EO Triumph listed as a 7x35; only an 8x42. The Triumph shows a minimum IPD setting of 55mm which may be too wide for a five year old.

Bushnell doesn't even list the IPDs of their 7x35s but they do say the prisms are BK7 instead of the preferred BaK4. Do you want to take a chance that they will fit? I doubt they go down to a minimum of 50mm.

Only the Yosemite binos have the 50mm minimum IPD that I think would guarantee a fit for a youngster. They use the premium BaK4 prisms as well. The price is higher but the chances of getting satisfaction from them is higher as well.

Rich

#12 mv1612

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Posted 07 December 2012 - 01:47 PM

I don't see the EO Triumph listed as a 7x35; only an 8x42. The Triumph shows a minimum IPD setting of 55mm which may be too wide for a five year old.

Bushnell doesn't even list the IPDs of their 7x35s but they do say the prisms are BK7 instead of the preferred BaK4. Do you want to take a chance that they will fit? I doubt they go down to a minimum of 50mm.

Only the Yosemite binos have the 50mm minimum IPD that I think would guarantee a fit for a youngster. They use the premium BaK4 prisms as well. The price is higher but the chances of getting satisfaction from them is higher as well.

Rich


Thanks. Excellent information! So things all point towards choosing the Yosemites for the girl: weight, IPD, Bak4. For me, I guess the Bushnell Falcon will be good enough.

Time to go shopping :D

#13 Jay_Bird

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Posted 07 December 2012 - 02:04 PM

All seem to agree the Yosemite are well made in 6x30 and 8x30. Binoculars are the sum of a lot of build quality and optical factors, the Yosemite seem to be a good combination of those. A neightbor loaned me a generic Japanse 8x30 when I was in middle school as first astro binocular, it was no slouch, so don't worry about 30mm size.

Check the IPD specs and maybe a Bushnell H2O 8x42 Porro model is another option for $60-$80 for dad if not for daughter.

#14 mv1612

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Posted 07 December 2012 - 02:27 PM

I was just been told that the Yosemite has a narrow field of view... 45 deg... Wouldn't this be kind of tunnel-like?

#15 ronharper

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Posted 07 December 2012 - 02:37 PM

Yes. The 8x has a nice wide field.
Ron

#16 mv1612

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Posted 07 December 2012 - 02:41 PM

hmmm.....

#17 ronharper

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Posted 07 December 2012 - 03:48 PM

What I meant was, the 6x is narrow, the 8x is wide! Sorry bout that...
Ron

#18 Simon S

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Posted 07 December 2012 - 04:37 PM

A 7x35 or even an 8x40 makes for good constellation exploration when your finding your way around the stars.
?Bare in mind modern x35's and 8x40's are rare, so if your using an old binocular make sure it's not full of muck.

#19 ronharper

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Posted 07 December 2012 - 05:33 PM

A PM from another member has raised another question about my meaning, of the field width of the 8x and 6x30 Yosemites. I'll just answer publicly because I do want to help the OP out.

The true fields of the 6x and 8x are 8 degrees and 7.4 degrees respectively. So in that sense, the 6x is wider.

But, the appearance of "tunnel view" arises from a narrow apparent field. That is, how wide the view looks to am observer. To obtain a good approximation of the apparent field, you multiply the true field width in degrees by the magnification. This gives apparent fields for the 6x and 8x of 48 degrees and 59.2 degrees.

That is a big difference at the eyepiece. A common rule of thumb is that anything less than 50 degrees is unacceptably narrow, and that the minimum that can be considered truly "wide field" is 60 degrees. I think those are pretty good places to draw the arbitrary lines.
Ron

#20 KennyJ

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Posted 07 December 2012 - 06:09 PM

Ron is correct(as usual)about those considerable differences.

Others are correct about the Yosemite probably being the only model with suitably narrow I.P.D for such a young one.

I once bought an aforementioned Bushnell 8 x 42 H2O Porro for one of my ADULT daughters,and it's still going strong after 9 years.Very good value for money,but the minimal I.P.D setting is far too wide for a child.

Kenny

#21 mv1612

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Posted 07 December 2012 - 07:38 PM

I understand the difference between TFOV and AFOV, no problem with that (I'm just in the process of changing the eyepieces for my dob, because I want a larger field of view). I know that I would't use a 48 deg eyepiece on my scope. But I'm not sure if the sensation is equivalent, the same AFOV in the eyepiece of a telescope or on a binocular (I don't have any experience whatsoever with binoculars).

I think I will still buy the 6x Yosemite. The exit pupil on the 8x is too small if it is to be used for the night sky, I think. I will take a decision as soon as possible...

Thanks for your help, it was invaluable.

Virgil.

#22 Tony Flanders

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Posted 08 December 2012 - 07:33 AM

The exit pupil on the 8x is too small if it is to be used for the night sky, I think.


I don't agree at all. For any given aperture, smaller exit pupils will almost always show you more. 8x30 binoculars will show you much fainter objects and much greater detail in small objects than 6x30s.

Note that with interchangeable-eyepiece telescopes, where there's complete freedom of choice, most people choose exit pupils of 2.5 mm or smaller. In 30-mm binoculars, that would translate to 12x30.

The main reason to prefer lower magnifications (i.e. bigger exit pupils) is true field of view. But that's less true in this particular case than in most.

Also, some people find the less-bright view through a smaller exit pupil less aesthetically appealing. I can't argue with that since it's an entirely subjective judgment.

#23 Mark9473

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Posted 08 December 2012 - 09:02 AM

The point is, Tony, not that 8x30 shows you more than 6x30 - which is true - but that an 8x30 has a rather small exit pupil compared to e.g. 8x40 or 8x50 binoculars.

One of the key attributes of binocular viewing is the way two-eyed viewing reacts to bright colourful images. A 3.75mm exit pupil is borderline for that, if not already too small.

#24 Tony Flanders

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Posted 08 December 2012 - 09:32 AM

The point is, Tony, not that 8x30 shows you more than 6x30 - which is true - but that an 8x30 has a rather small exit pupil compared to e.g. 8x40 or 8x50 binoculars.

One of the key attributes of binocular viewing is the way two-eyed viewing reacts to bright colourful images. A 3.75mm exit pupil is borderline for that, if not already too small.


I'm not entirely sure what you're saying. If you are repeating my previous point, that some people find the brighter image more aesthetically pleasing, I can't argue with that.

On the other hand, there was a recent thread in this group lamenting the fact that it's so hard to find binoculars with 4-mm exit pupils, which the poster (and many others) felt gave the best possible compromise between field of view, brightness, and optical quality -- the point being that almost everybody's eyes show much sharper images when masked down to 4 mm. Again, that's an aesthetic preference, impossible to argue with.

But if you're saying that the benefit of two-eyed viewing over one-eyed viewing decreases for smaller exit pupils, that's demonstrably incorrect.

As for color, the only things in the night sky that appear colored are stars, the bright planets, the Moon (to a small extent) and a handful of nebulae. All of those will appear more colorful, not less, in 8x30s than in 6x30s.

Are you making your statement based on direct experience or hearsay?

#25 Mark9473

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Posted 08 December 2012 - 09:55 AM

My direct personal experience is that star colours are more vivid with larger exit pupils.






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