William Optics 1.25" Swan Series Eyepiece - 20mm
This item is discontinued by the manufacturer and is no longer available.
Stock count is accurate & shown in real time.
- This item is out of stock.
- Sign up for back-in-stock alerts to be notified when this item becomes available (account login required).
- This item is out of stock.
- Sign up for back-in-stock alerts to be notified when this item becomes available (account login required).
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 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 1.25" 20mm 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.
Outstanding chromatic aberration correction.
Excellent contrast and light throughout for sharp viewing.
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: 17mm.
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.
Other Information
- Country of Manufacture: Taiwan
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 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 1.25" 20mm 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.
Outstanding chromatic aberration correction.
Excellent contrast and light throughout for sharp viewing.
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: 17mm.
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.
| Manufacturer | William Optics |
|---|---|
| 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 Type | Tapered barrel |
| Protective Storage Container Included | Yes - Free Agena Eyepiece Container |
| Protective Plastic Storage Container Size (Sold Separately) | Agena 42x80mm |
| End Caps | 2 |
| Parfocal | Yes |
| Weight | 100 g |
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 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 1.25" 20mm 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.
Outstanding chromatic aberration correction.
Excellent contrast and light throughout for sharp viewing.
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: 17mm.
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.
Other Information
- Country of Manufacture: Taiwan
| Manufacturer | William Optics |
|---|---|
| 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 Type | Tapered barrel |
| Protective Storage Container Included | Yes - Free Agena Eyepiece Container |
| Protective Plastic Storage Container Size (Sold Separately) | Agena 42x80mm |
| End Caps | 2 |
| Parfocal | Yes |
| Weight | 100 g |