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Thread: To What Degree Do Eyepiece Lens Elements Lower Light Transmission?

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    Default To What Degree Do Eyepiece Lens Elements Lower Light Transmission?



    For example would a 30mm eyepiece with 4 lens elements show a noticeably brighter image, than a same size eyepiece with 6 lens elements? Thanks you very much.

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    Default Re: To What Degree Do Eyepiece Lens Elements Lower Light Transmission?

    If the glass quality and manufacturing are exactly equal then yes, less elements will have more light throughput and less scatter or ghosting.

    BUT, you also have to take into account how thick the individual elements are and how the lens surfaces are coated. Coated, fully coated, fully multi-coated which effects light transmission also.
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    Default Re: To What Degree Do Eyepiece Lens Elements Lower Light Transmission?

    It is not just the number of elements, but also EP design, quality of materials and finishes, coatings, etc. 8 elements Vixen SLVs easily outperform lesser quality 3-6 elements EPs.

    However, premium quality EPs with minimal number of glass-to-air surfaces would typically have slightly better transmission than premium EPs with more glass-to-air surfaces.

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    Default Re: To What Degree Do Eyepiece Lens Elements Lower Light Transmission?

    If you are looking for ~30mm EP for faint fuzzes, well made Plossl is your best bet!
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    Default Re: To What Degree Do Eyepiece Lens Elements Lower Light Transmission?

    Hello Refractordude,

    as a rule, the eyepieces don't differ much in transmissivity on the green/yellow wavelengths (540nm - 600nm)

    Where they really differ are the short blue wavelengths, and this is critical when visually observing the HII diffuse nebulae, and the spiral structures in the galaxies.
    And this loss of the transmissvity is mainly due to the glass materials and cements between the lenses in the EP.

    I am using the old Zeiss and Leitz/Leica eyepieces, whenever the highest transmissivity and contrast on the blue wavelengths is required.

    Best,

    JG
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  6. The Following 2 Users Say Thank You to j.gardavsky For This Useful Post:

    John Baars (11-10-2018),SpyderwerX (11-09-2018)

 

 

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