William Optics 1.25" Swan Series Eyepiece - 20mm

Our Price: $79.00
Free shipping for this item in the US Click here for more info

Continental US Customers:
All items we sell ship for free within the Continental US. Shipping will be via the cheapest shipping method which will vary depending on the items in your order. During checkout, you may also be shown other optional faster shipping choices.

US Customers in Hawaii and Alaska:
Free shipping applies to almost all products. A few large telescopes and mounts are excluded from this free shipping offer. For these items, please contact us to obtain a shipping quote before you check out using the online shopping cart.

International Customers:
Free shipping does not apply to international orders. During check-out, you will be presented with several shipping choices and costs. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions.

In stock (7 Available)
Ships by Next Business Day
Our Product ID: E-WO-SWAN20
Manufacturer SKU: E-SWA20
Item Can Ship: Worldwide
William Optics 1.25" Swan Series Eyepiece - 20mm

More Views

Website Special - FREE Agena plastic bolt case / storage container included with this eyepiece (a $3.25 value)!

Product Details

The Swan eyepieces are super wide angle designs with a 72° 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, 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 5-element super-wide angle 9mm SWAN EP's panoramic views at 72 deg. FOV will leave you speechless!  A premium eyepiece at a fraction of the cost its worth!

Super Wide FOV
Outstanding super-wide field of view: 72 deg. FOV
Fully Multicoated lenses for excellent transmittance.
Reduced chromatic aberration.
Improved contrast compared to similar EPs.

Great Contrast
Internally fully blackened (lens edges and internal spacers).
No flaring or ghosting on high-contrast objects.
Parfocal.

Light and Easy
Soft rubber eyecup.
Long eye-relief: 12mm.
No internal reflections, kidney beaning or other distracting distortions.

Terrific Fit and Finish
High-resistance anodized black barrel.
Smooth design for no hook up in your focuser.
Threaded for use with 1.25" filters.

Eyepiece Series SWAN Series
Focal Length 20mm
Barrel Size 1.25" (31.7mm)
Apparent Field of View (Mfg Specified) 72°
Eye Relief (Designed) 17mm
Filter Threads Standard 1.25" Filter Thread (M28.5 x 0.6)
Coatings Fully Multi-Coated
Lens Elements 5
Lens Groups 4
Blackened Lens Edges Yes
Barrel Safety Recess Tapered Barrel
Barrel Type Tapered barrel
Protective Plastic Storage Container Yes - Free Agena Eyepiece Container
Protective Plastic Storage Container Size Agena 42x80mm
End Caps 2
Parfocal Yes
Weight 100 g