Binoculars for astronomy

[cloesita]

Hello, i'm searching a binoculars for astronomy of 20x80mm. I'm thinking between 3 models: BRESSER Astro, other by brand Alltelescopes and BARSKA XTRAIL BINOCULAR whit similar characteristics: BAK4 and multi-coated prisms. Which of these binoculars do you recommend to me for astronomy for the prisms optical quality? Thanks

[BobDob]

Hello cloesita, and welcome to astronomy forum! I am not the resident expert on bino's for astronomical use. I understand the BAK4 prisms are considered essential as is not just multi-coated, but FULLY coated for our needs. You may want to reevaluate your choices on the basis of being fully coated, or not.

If you have an opportunity to do some reading, AF has a sub-forum under Telescope Forum for astro-bino's specifically. You'll find a heap of good information there.

Please let us know what you decide to go for and how you like them. And, thanks for joining us.



Bob

[roverich]

Hi Cloesita ...Welcome aboard the forums ...

Like bob was saying ..Fully multi coated lenses will allow more light to pass through the lenses and reach your eyes ....And don't buy 20x80 binoculars unless you are going to mount them on a tripod or some other kind of holder ...You might be able hand hold 20x80s for a short while , but not for very long ...The best binoculars for astronomy would be something in the 10x50 range but nothing stronger than 10 power ...

[metroman]

Hi,
I have just purchased some Helios 10 x 50 (Ultimate High Resolution Series) Bak-4 prisms. These are very good bins, I have tried with zoom bins, but zooms are no good.
Martin

[Gib007]

I'm thinking of buying 7x50 with BAK-4 prisms. Are these any good??

[roverich]

Hi Gib007 ...It depends on the quality of the binoculars ..I know that isn't the answer you want to hear but 7x50 binoculars can be had in a variety of quality optics ...If you buy them , what brand are they ? I found a deal on used pentax a bunch of years back and pentax are still great quality ... as are Nikon,Fujinon,Zeiss,Myauchi and i am sure there are others ...But it is like everything else , you get what you pay for these days ... A good pair of Nikon's or Pentax can be had from Amazon.com: Online Shopping for Electronics, Apparel, Computers, Books, DVDs & more for 100-150 dollars ...

[Gib007]

Hi Gib007 ...It depends on the quality of the binoculars ..I know that isn't the answer you want to hear but 7x50 binoculars can be had in a variety of quality optics ...If you buy them , what brand are they ? I found a deal on used pentax a bunch of years back and pentax are still great quality ... as are Nikon,Fujinon,Zeiss,Myauchi and i am sure there are others ...But it is like everything else , you get what you pay for these days ... A good pair of Nikon's or Pentax can be had for 100-150 dollars ...

Hi roverich, thanks for your reply. I was actually looking at the "Fieldmaster 7x50 Porro Classic Binoculars" from the "Pulsar Optical" UK online store. They are £46.99. This is the usual marketing hype (statistics are at the bottom):

The Fieldmaster 7x50 is a premium quality classic! But at our price of £49.99 it's top quality that's easily affordable!

The 7x50 Fieldmaster provides high-definition images that will please the most discerning observer. Helios Bak 4 optics and solid, reliable mecanics make this bino a stunning bargain.

These binos are a great general use size and are regarded as one of the best sizes for astronomy - with a great relationship between magnification and aperture, the 7x50 size will deliver stunning views of the night sky - much brighter than binos with a higher magnification to aperture ratio.

A great general purpose glass, the Fieldmaster is a serious binocular for the discerning observer: all lenses and prisms are BaK-4 glass with all glass surfaces fully multi-coated to minimise reflections and maximise image brightness and contrast. The eyepieces feature fold-down rubber eyeguards - making this binocular ideal for spectacle wearers. The rugged rubber armoured body has the comfortable top quality feel you would expect from a premium binocular. A tripod bush allows use of a camera tripod for support and increasing the usefulness of this glass for detailed terrestrial or astronomical observations.

Supplied with soft padded carrycase, neck strap and front and rear dust caps.

Specification:

Objective Diameter (mm): 50

Magnification: 7x

BaK-4 Porro Prism design

Fully Multi-coated optics (FMC)

Field of View: 105 @1000m

Width (mm): 180 x 190 x 60mm

Weight: 825g

Fully Rubber armoured

A classic 7x50 with class Bak 4 optics.

[roverich]

Those sound like good binoculars ...But it is like you say , marketing hype .....I would look at the bresser binoculars also ..They are good quality from what i hear and are on sale right now for 10 pounds less than the ones you listed ... I need adjustable diopiters on at least one of the eye pieces and the ones you linked to dont list the diopeter adjustment ..Something to think about ..My eyes are old and need the adjustable eyecups ...

[Carlos_dfc]

Hi there Gib007

I'd also recommend taking a look at the Bresser 10x50s
Bak-4 prisms - 65° AFOV - Pin-sharp stars across 70% of the FOV (quite good by binoc standards) - and very cheap if you shop around.
Minor criticisms:-
They do show some internal reflections if you point them near a bright light-source - but if you want them for astronomy you won't be doing that much anyway.
Not the greatest build-quality - but adequate (better than you'd expect at the price) - I've owned 3 for over 2 yrs with no problems - my oldest pair (4yrs) lives in my car glovebox, and is still fine.


The thing I find with 7x50 bins is that they do tend to have a rather narrow apparant field of view (AFOV)
105m @ 1000m is pretty poor for a 7x instrument - my Bresser 10x50 gives 114m @ 1000m
43% more magnification, yet they still manage a wider field of view.

105@1000 in a 7x is an AFOV of only 42° (akin to looking down a tube)
114@1000 in a 10x is AFOV of 65° (like looking out of a window by comparison)

105@1000 is also a True Field of View (TFOV) of about 6°
114@1000 works out to 6.5° TFOV

So in short - The Bresser 10x50 will give an even wider view of the sky - the wider AFOV also looks much nicer - You get extra magnification (more magnification means better contrast - DSOs stand out against the background better)
And the Bressers are cheaper.

One more thing - avoid 'Pulsar' - I've heard some horror stories about them and ther sister company 'Scopes'n'Skies' - mostly customer service problems (orders going astray - long waits - that sort of thing)
If your item is in stock (and their word on that is notoriously unreliable), then things often go very well - but if there's a problem, they can be a nightmare.

Telescope House currently have the Bressers at £28-99
If you decide to go for the Bressers - check out your local 'Lidl' shops first - the same binocs often come up on offer for between £9-99, and £15-99 - sometimes branded 'Meade', but they are still the same binocs. (Meade and Bresser are the same company)

I've bought 3 of these from Lidl, and I'm not exaggerating when I say they are as good as a lot of £60 - £80 10x50s I've looked through (that's why I bought 3 of 'em - LOL)
One for general use - one lives in the car, and if it gets banged around, at £10-£15 it's no big deal to replace - the third pair is my 'spare'.

I also have an Excel file I'm working on - showing comparative fields of view of different binoculars - You can have a copy of what I've got so far if you like - just drop me a PM with your email addy.
Best FOV I've found so far in a 7x50, are the 'Willam Optics 7x50 ED' - AFOV 53° - TFOV 7.6°
But they do cost about £180 - £200

[Gib007]

Thanks very much for your tips. I will look into the 10x50 Bresser's with BAK-4 prisms. It's certainly within my price range so I'd be happy to buy those!
Thanks again.

By the way, it's a shame if I have to avoid Pulsar Optical because the telescope I want (Skywatcher Explorer 300P NEQ6 Pro SynScan GoTo 12") is £1,239.99 there whilst it's around £1,489 everywhere else..
Perhaps it is an error on their part (if as you say, they are notoriously unreliable!)?