SWAN 9mm Eyepiece

The William Optics 1.25" Swan 9mm Eyepiece can be put to use for all types of observing, and with all telescope types, however they are most suited for use with focal ratios up to f/6 and above.

They have soft roll down rubber eyecups for eyeglass use, and dust caps for both ends of each eyepiece. A soft protective drawstring-equipped velvet storage bag is standard equipment with each. This 5-element super-wide angle gives panoramic views at a 72 degree field of view.

This simple but innovative five lens optical system has generally higher contrast when compared to other more complex optical designs often found in various other super wide angle eyepieces which may use up to eight lenses.

All lenses are fully multicoated for high light transmission. Lens edges and internal field stops are blackened to reduce internal reflections and improve contrast. The rubber grip ring is advantageous for safer handling of the heavier 2” eyepieces when sporting gloves in cold temperatures.

William optics are well renowned for their superb array of optical components. A considerable number of amateur astronomers employ them simply because the are convinced that they do the job just as as well as others costing twice the price.

SWAN 9mm Eyepiece


  • Model SWAN 9
  • Focal Length 9mm
  • Lens Structure (#Elements/#Groups) 5/4
  • Field of View 72
  • Eye Relief 12mm
  • Barrel 1.25"
  • Coating FMC
  • Parfocal Yes
  • Weight 70g

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