William Optics SWAN Eyepiece

William Optics SWAN Eyepiece

  (3 Reviews)
✓ 2 year warranty


6x in stock shipped 1-2 working days

About this product

Model:  WOswan-1
Part Number:  E-SWA09

William Optics Swan eyepieces are super-wide-angle designs with 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 SWA 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 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 are remarkably good all-round eyepieces when used with telescopes with focal ratios up to f/6 and above.

Technical specs:
9mm Swan, 1.25" barrel
5/4 lenses/groups
72 degree FOV
12mm eye relief
Weight - 70g

15mm Swan, 1.25" barrel
5/4 lenses/groups
72 degree FOV
14mm eye relief
Weight - 90g

20mm Swan, 1.25" barrel
5/4 lenses/groups
72 degree FOV
17mm eye relief
Weight - 100g

25mm Swan, 2" barrel
5/3 lenses/groups
72 degree FOV
Eye relief 21mm
Weight - 330g

33mm Swan, 2" barrel
5/4 lenses/groups
72 degree FOV
25mm eye relief
Weight - 410g

40mm Swan, 2" barrel
5/3 lenses/groups
70 degree FOV
28mm eye relief
Weight - 570g

Customer reviews

Average Rating (3 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
25mm WO SWAN Eyepiece
31 March 2022  | 

Absolutely wonderful, like looking at a picture window of space! Beautifully made and finished item and a real joy to use giving such a large panoramic and clear view. I am not experienced enough to make. a judgement on optical quality but it seems superb to me.

Rating (max 5):  
Good one for a Mak
05 May 2016  | 

I got the 15mm version to use with my Celestron C90 Maksutov, it gives 83x. Image quality is very good and distortion free (no barrel or pincushion that I notice). No chromatic aberration/astigmatism either, stars are sharp to the edge. The only complaint is that I don't believe the advertised 14mm eye relief; it's more like 10mm.
I've no idea how it would perform in a faster scope.

Rating (max 5):  
wide view eyepieces
31 December 2013  | 

I use these eyepieces with my mack 180 pro 9 and15 are very good moon and planets people say that skywatcher mac carnt do deep sky using 25 to 40mm eyepieces it can


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