- Focal Length: 40mm
- Barrel Size: 2"
- Apparent FoV: 72 Degrees
- Eye Relief: 28mm
William Optics 40mm Swan Eyepiece - 2"The Swan eyepieces are super wide angle designs with 72 degree apparent field of view. They use simple but sophisticated five-lens optical systems for generally higher contrast than the more complicated optical designs used in some other super wide angle eyepieces that 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 eyepiece rubber grip ring is useful for safer handling of the heavier 2" eyepieces in cold weather when wearing gloves. The eyepieces have soft roll down rubber eyecups for eyeglass use. They can be used for all types of observing, both day and night!
The William Optics SWAN 40mm Eyepiece has soft roll down rubber eyecups for eyeglass use. They can be used for all types of observing, with all telescope types, but they are recommended for use with focal ratios up to f/6 and above. Dust caps are provided for both ends of each eyepiece. A soft protective drawstring-equipped velvet storage bag is standard equipment with each.
This 4-element super-wide angle 40mm SWAN EP's panoramic views at 72 deg. F.O.V. will leave you speechless!
William Optics 40mm SWAN Eyepiece Features
- Fully Multicoated lenses for excellent transmittance..
- Reduced chromatic aberration.
- Improved sharpness and contrast throughout the field.
- No internal reflections, kidney beaning, pin-cushion or other distortions.
- Smooth design for no hook up in your focuser.
- Threaded for 2" filter usage.
- Rubber grip ring for safe, comfortable handling.
Dust Caps IncludedYes
Eye Guard IncludedYes
Eye Relief19mm & Up
Eyepiece Apparent FOV72 degrees
Eyepiece Eye Relief28mm
Eyepiece Special FeatureNone
Field StopNot supplied by manufacturer
Lens Elements & Groups5 elements & 4 groups
ModelWilliam Optics Swan
Optical DesignWide Angle
Warranty2 Year Warranty
- William Optics Swan 40mm 2" Eyepiece
- Velvet Protective Bag
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