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Thread: Question For Owners Of The Celestron Skymaster 80x20 Bicnoculars

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    Default Question For Owners Of The Celestron Skymaster 80x20 Bicnoculars



    What is the actual aperture of the Skymaster 20x80 binoculars. My Oberwerk LW 15x70 is 64. The people at Oberwerk stated that the Skymaster 20x80 is around 75 percent of 80.

    Thanks
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    Default Re: Question For Owners Of The Celestron Skymaster 80x20 Bicnoculars

    Quote Originally Posted by refractordude View Post
    What is the actual aperture of the Skymaster 20x80 binoculars. My Oberwerk LW 15x70 is 64. The people at Oberwerk stated that the Skymaster 20x80 is around 75 percent of 80.

    Thanks
    Hello refractordude,

    it goes 1, 2, 3, 4:
    1. Turn the binoculars focused to infinity and with the eyepieces against flash light
    2. Take a piece of semi-transparent paper, which will be your screen
    3. Put the paper on the front lens
    4. Mark with a pencil the circumference of the bright disc on the paper

    and this is the effective aperture of the binoculars.

    The 75% of 80mm effective aperture on the 20x80 binoculars, as someone told you at Oberwerk, is an utter nonsence. Why would anyone pay for the 20x80 binoculars with the useful aperture of just 60mm?

    I always get a bad feeling when the technical support guys of the sales don't know the elementary things.

    It goes similarly with the telescopes to check vignetting obstacles, like undersized focusers, wrong placed baffles, ...

    Happy testing,

    JG
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    Binoculars: Leica Ultravid 7x42, 8x42HD; Swarovski EL 8.5x42 Swarovision; Nikon 10x70 Astroluxe; Docter Nobilem 7x50 Porro; Jenoptem 7x50W, 10x50W; BA8: 10.5x70, 15x85; 25x100FB, AsahiPentax 8x40, Refractors: Sky-Watcher 150mm/750mm; Leica APO Televid 82mm (25x-50x WW ASPH); EPs:Baader Classic Orthos; Fujiyama ortho, Leica B WW, ultrawide zoom ASPH, Periplan GF, HC Plan S, L; DOCTER UWA; Wild UW mil; Tele Vue Delos, Nagler Zoom, Plössls; Swarovski SW; Pentax XW; ZEISS diascope B WW T*, Carl Zeiss E-Pl; Hensoldt mil; Filters: Astrodon, Astronomik, Baader (CCD), TS;
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    Default Re: Question For Owners Of The Celestron Skymaster 80x20 Bicnoculars

    Just did a day time side by side test of my three binoculars. My Celestron Cometron 7x50 binoculars are brighter than my Oberwerk LW 15x70 binoculars. My Oberwerk LW 15x70 are brighter than my Celestron Skymaster 20x80 binoculars.

    Thanks J. Gardavsky. I snipped the info into my astro usb device.
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    Default Re: Question For Owners Of The Celestron Skymaster 80x20 Bicnoculars

    JGardavsky:

    Tech support at Celestron admitted that the Skymaster binoculars have low end coatings. According to tech support, wider aperture does not always result in greater brightness. Thus, 64mm aperture with better coatings, can go deeper for DSO than 80mm aperture with cheapo coatings. He also said something about the Skymasters not being coated on both sides. Sent the Skymasters back to Amazon for a full refund. Amazon pays for shipping, which is great service. In the near future I may buy these https://www.amazon.com/BARSKA-AB1241...8-6&th=1&psc=1. I may get the 25x100 for $60 more.
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    Default Re: Question For Owners Of The Celestron Skymaster 80x20 Bicnoculars

    Hello refractordude,

    you have decided right.

    On your place, I would go for the 25x100 Oberwerks (these are the HK big binoculars from Kunming companies)
    https://oberwerk.com/product/oberwerk-25x100mm-deluxe/
    which offer excellent brightnes and contrast, and very good color rendition.
    Read the product description, and pay attention especially to this sentence:
    Features full broadband multi-coating (all air-to-glass surfaces, including prisms)
    I have had them for a short test, and the only drawback has been the eye relief at the eyepieces, I have experienced as a bit too short.

    As a cheaper alternative there are the 25x100 FB big binoculars from Kunming companies, coming under different brand names, like, https://www.amazon.com/Orion-9326-25...gateway&sr=8-5
    These have the same front lenses like the HK, but smaller prisms, and different eyepieces with a longer eye relief.
    These are the 25x100 I am using since many years, and I have them with the original FB name, not rebranded, and from the old times as they have been promoted on the western markets.
    With these, I have nailed down all Messier objects, and hundreds more.

    Best,

    JG
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    Binoculars: Leica Ultravid 7x42, 8x42HD; Swarovski EL 8.5x42 Swarovision; Nikon 10x70 Astroluxe; Docter Nobilem 7x50 Porro; Jenoptem 7x50W, 10x50W; BA8: 10.5x70, 15x85; 25x100FB, AsahiPentax 8x40, Refractors: Sky-Watcher 150mm/750mm; Leica APO Televid 82mm (25x-50x WW ASPH); EPs:Baader Classic Orthos; Fujiyama ortho, Leica B WW, ultrawide zoom ASPH, Periplan GF, HC Plan S, L; DOCTER UWA; Wild UW mil; Tele Vue Delos, Nagler Zoom, Plössls; Swarovski SW; Pentax XW; ZEISS diascope B WW T*, Carl Zeiss E-Pl; Hensoldt mil; Filters: Astrodon, Astronomik, Baader (CCD), TS;
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    Default Re: Question For Owners Of The Celestron Skymaster 80x20 Bicnoculars

    Hi refractordude!

    Good luck with your ongoing search for quality large binos. I don't know if you have read this article, but I find that while it is ostensibly comparing 3 top end large binos, it gives some fascinating insights into binocular optics in general as he picks up a lot of issues and examples from other binoculars. Issues such as % illumination of the exit pupil, coatings, size of prisms, vignetting, control of CA, baffling, true objective diameter, true resolution, size of true sharp field, different reasons for image brightness etc. are covered. It is a great read, and might give you some good insights in your search: https://www.cloudynights.com/article...tak22x60-r2333

    (and, as an aside, the article confirms for me that if (heaven forbid!) I had to have only one pair of big binoculars, it would be my Tak 22x60's!)

    All the best,

    Dean
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    12" home-made dob, Celestron 150 f5, Tak TSA102, TV 76, Celestron 800CPC, ETX 125
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    Eyepieces: My favourites are my Televue 32mm plossl, Nagler 13mm T6, Nagler 3-6mm

 

 

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