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Purchasing binoculars for stargazing advice

  1. Feb 20, 2015 #1

    cristo

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    I want to buy some binoculars, but since I'm new to this thought I'd ask for some advice. I've found a few candidates on amazon, what do you reckon?

    https://www.amazon.com/Nikon-8247-ACULON-Binocular-Black/dp/B00B7LQ9QU

    https://www.amazon.com/Orion-09332-Scenix-Inches-Binoculars/dp/B00E3QH60E

    Then these are really cheap (but maybe for a reason..): https://www.amazon.com/Celestron-UpClose-10x50-Binocular-71256/dp/B006ZN4TZS/

    Does anyone have some advice? Are any of these any good, or do you have some other recommendations for a first pair?
     
  2. jcsd
  3. Feb 20, 2015 #2
    It depends on your intended use. For daytime land use any of those might do. For nighttime viewing of stars and the like, specs become much more critical.
     
  4. Feb 20, 2015 #3
  5. Feb 20, 2015 #4

    cristo

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    I should have been more specific - I'm after an pair to view the stars and the night sky, not anything serious, just a pair I can carry around (so they need to be relatively compact). Those you mentioned look huge, and I'm not sure I'm keen on burning out my eyes!
     
  6. Feb 20, 2015 #5
  7. Feb 20, 2015 #6

    phyzguy

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    One rule of thumb is that, for nighttime viewing, the ratio of (aperture in mm) / magnification should be approximately 7mm. If this is the case, the exit beam of the binoculars will fill your night-adapted pupil, which is about 7mm in diameter. This allows you to see the faintest possible objects. Given this, the larger the aperture, the fainter the object you can see, but as the aperture gets larger, the binoculars get larger and heavier. 7x50mm binoculars are considered an ideal first set of astronomical binoculars. I have a set of 11x80mm Orion binoculars which give excellent images of the night sky, although the power of 11 makes them a challenge to hold steady. I can see Jupiter's moons easily, and low surface brightness objects like the Andromeda galaxy are also easy to see.
     
  8. Feb 20, 2015 #7

    cristo

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    Thanks, I think I'll go for one of the 7x50's above, then (the Nikon's are mentioned in the article that Greg links to, and that you have a pair of Orion makes me think either will be a decent purchase as a first pair).

    And sorry for the non-descriptive thread title, @Greg Bernhardt !
     
  9. Feb 22, 2015 #8

    wabbit

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    Good choice, you can't go wrong with a good pair of 7x50s and you'll keep using it for a long time after you've bought tons of other equipment. Great for scanning the milky way, easy to hand hold. Enjoy your stargazing!
     
  10. Feb 25, 2015 #9
    Don't take me too seriously about burning your eye on the full moon with the Fujinon 10x70 FMT-SX Polaris. It is bright though, and take some getting used to the experience- a most beautiful view of the moon. You can almost see depth in the Moon's mountains. And the shadows really pop out.

    I might have to pick up a pair of the 7x50, the Nikon perhaps. Your right, sometimes the 10x70s are just too big. I might use 7x50s more often.

    Let us know what you get and what you think of them.
     
  11. Feb 26, 2015 #10

    Andy Resnick

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  12. Feb 26, 2015 #11

    wabbit

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    The advantage of 7x50 is that they are lightweight and versatile - pick them up on a whim and look at birds or stars or whatever. 10x70s can be great (no doubt about that regarding the Fujinon) and surely not a purchase you'd regret - but they're bigger and more or less require some tripod or monopod to be used comfortably : to me, more a second pair than a first.
    But either is fine really - just avoid the cheap $30 ones unless your budget is really tight - they may well be serviceable enough but very roughly $100 seems to be where you start getting good stuff. After that there's no limit! But you don't need a Ferrari to get a good drive.
     
    Last edited: Feb 26, 2015
  13. Feb 26, 2015 #12
    I have had the Celestron Skymaster 12x60 binos for 7 or 8 years. Their reputation for warranty is good but I have heard it can be a bit of a crap shoot on initial quality. I was lucky enough as mine were fine out of the box. But I did read some people have collimation issues and have to make a warraty claim.

    The 12x60s are at my limit for hand holding (I lean against a wall to steady myself or lie on my back) and they came with a tripod adapter. The new 12x60s have the adapter as an extra cost option.
    The moon looks great and I can easily see Jupiters Galilean moons as well as a faint view of Andromeda. Saturns rings are visible but look like a smudge.

    Maximum night adapted pupil diameter shrinks as people get older so you may not benefit as much from a larger "exit pupil". (I'm not saying you are old but you have been around PF for a while.)
     
  14. Feb 26, 2015 #13

    cristo

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    I didn't know this! How rapidly does the pupil diameter shrink? I'm 30 (so I'll let you decide whether that's old or not!) - do you think I'd still benefit from the larger exit pupil?
     
  15. Feb 26, 2015 #14
    I'm sure it is varied by individual. But IIRC it is about 8mm in children down to about 4mm in the elderly.

    Hey! google says: Looks like you are still good to go.

    pupil_size_chart(Mar2011).jpg
     
  16. Feb 26, 2015 #15
    Thanks for looking this up- very interesting chart. But it look like "it needs more research and more study participants", so says every scientist.
     
  17. Mar 5, 2015 #16

    turbo

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    True, and remember that most "scientists" aren't astronomers. Simply placing a participant in a dark room and measuring their pupil diameters after a short time is a really poor approximation, at best. Amateur astronomers can shoot this chart down with ease. It takes me at least 20-30 minutes for my eyes do become dark-adapted enough so that I can get good performance from my scopes. Did the people who compiled the chart invest at least 30 minutes in the dark plus testing on each participant? I doubt it. "Scientific" studies should not be conducted on humans by people with no real experience in physiology. Such studies are unethical, and can result in harm.
     
  18. Mar 7, 2015 #17

    Chronos

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    JC Bradley, lead author of the study referenced by montoyas, is a licensed ophthalmologist, so it appears safe to assume he has credentialed expertise in ocular physiology. The study did not require 30 minutes of dark adaptation time [more like one minute], hence, also safe to presume no conclusions regarding potential night vision acuity were suggested. I agree that renders it of questionable relevance to this discussion.
     
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