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Stargazing Zeiss Terra ED 10x42 Binos for stargazing?

  1. May 9, 2018 #1

    Doc Al

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    Any opinions about the Zeiss Terra ED 10x42 binoculars? OK for simple stargazing? (I have an opportunity to get them very cheap.) They are marketed for birdwatchers, so not sure if they'd be a good choice for simple sky/star watching.

    (As should be obvious, I am very much an amateur.)
     
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  3. May 9, 2018 #2

    phyzguy

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    For stargazing, you want the exit pupil to fill your dark-adapted pupil, which is about 7mm in diameter. This will give you the maximum light gathering ability. The exit pupil is the diameter of the objective divided by the magnification, so 4.2 mm in this case. So you will not see faint objects as well as with, for example, 7x50 binoculars. Also, with 10X magnification, it is hard to hold them steady unless you have them on a tripod. I have a pair of 11x80 binoculars, and I need to rest them on something to really see a good image that isn't dancing around.

    Having said all that, I'm sure you'd still see a lot of cool stuff with these binoculars, so if you have a chance to pick them up cheap, go for it!
     
  4. May 9, 2018 #3

    George Jones

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    I am 57. About 10 years ago, I went into an astronomy store and told an employee that, because of the size of exit pupil, I was considering 7x50s. Employee's blunt response: "You're too old for 7x50s." His point: because of my age, the size of my dark-adapted pupil mas probably less than 7 mm. Still, a 4.2 mm exit pupil i a bit small.

    The steadiness of the view is a function of both magnification and weight. The larger the magnification, the more every shake is enhanced. The heavier the bins, the harder they are to hold steady. I suspect that your 11x80s are heavier than the 10x42s.

    I agree.
     
  5. May 9, 2018 #4

    phyzguy

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    You're right. I'm sure they are a lot heavier. From that standpoint, 10x42s might be OK.
     
  6. May 9, 2018 #5

    sophiecentaur

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    They are for sale in UK at around £360 and Zeiss is a good make. If your "cheap" price is a lot less than that then you should buy them anyway. Just check they are collimated (that you can focus on something with your eyes relaxed).
    There is not doubt that you must use a tripod (adaptor is only a few quid) on a serious session. So you can be sure of not losing something you just spotted. You can also show it to someone else .
    The great thing about bins, compared with a ton of wonderful equipment is that you can have them with you at all times.
    And there are always birds everywhere.
     
  7. May 11, 2018 #6

    Doc Al

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    Thanks for the advice!

    LOL. In that case, I'm WAY too old for 7x50s. :eek:
     
  8. May 11, 2018 #7

    sophiecentaur

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    If you feel too feeble to lift 7X50s and hold them steady, I could suggest some fancy Canon binoculars with auto stabilisation. You could be reeling about under the weight but they would keep the image steady. (Lotsa money, though)
     
  9. May 11, 2018 #8

    Doc Al

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    My only feebleness is mental. o_O And, apparently, the size of my dark-adapted pupil. (Did not consider that it decreases with age!)

    And I am cheap! :smile:
     
  10. May 13, 2018 #9

    sophiecentaur

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    This article discusses the effect of pupil size and the spread over the ages of observers (and a lot of other stuff). The message is "it depends" so it certainly doesn't mean you shouldn't buy a nice pair of binos. (at a good price)

    You still get the other advantages like lack of Chromatic Aberration and good contrast. My Steiner Hawkes are lovely to use, despite having small objectives.
     
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