William Optics XWA 9mm 101 degree EP: Photos

[John]

First Light Optics managed to get one of these monsters for me to test and report back on. I've only glimpsed though it so far (literally just for a minute or two !) so it's far to early to conclude anything on the optics but I thought some photos might be of interest. 

I've included my 8mm Tele Vue Ethos for scale, itself a large eyepiece for an 8mm. Both are 1.25" eyepieces but the William Optics uses a novel and very nicely machined removable 2" skirt that actually screws into the 1.25" filter thread of the smaller diameter barrel. The Ethos uses a more usual hybrid barrel arrangement.

The fit and finish of the William Optics is very good and very much in keeping with other WO eyepieces such as the UWAN's and SPL's. Lens coatings and internal blackening look really well done.

In 1.25" mode the WO XWA looks and feels a little top heavy but it handles fine when you get used to the weight distribution. The rubberised eye cup is wide and rather hard and unyielding. It twists up about 10mm.

Comparing the eye relief in daylight, the WO XWA seems noticeably tighter than the Ethos. With the latter I can perceive the edges of the field of view in my peripheral vision with my eye gently pressed into the soft rubber eye cup but with the XWA I could not see the field edges without really pressing my eye into the eyecup aperture and consciously moving my eye around.  

The 9mm WO XWA eyepiece gives 177x with my 12" F/5.3 dobsonian but still shows over half a true degree of sky, enough to fit the whole of the Moon's disk in - should be quite a sight ! 

NB: The first and last photos show the Ethos with the 28mm Baader Fine Tuning Ring in place as a barrel extension. I use this to allow 2" filters to be attached directly to the eyepiece.

[Damo636]

Nice pics John, those two should make for an interesting comparison.

[alan potts]

My word that is a whopper, as you say the 8mm is big enough, looks nice though. I am waiting to see how the edges hold up in you faster scope, that extra 1 degree could the the straw that breaks the camels back.

Alan

[alan potts]

Just on a second look John, what is that black piece in the end of the 8mm E.

Alan.

[John]

Just on a second look John, what is that black piece in the end of the 8mm E.

Alan.

Do you mean the disk in front of the last lens and just below the 1.25" filter thread Alan ?

Thats always been there - part of the design of the eyepiece I assume.

[alan potts]

John,

No I meant the black extension sleeve on the 2 inch part of the Ethos, mine has not got one of those. I am assuming it is some sort of screw in affair that maybe allows the use of a 2 inch filter.

Alan.

[John]

John,

No I meant the black extension sleeve on the 2 inch part of the Ethos, mine has not got one of those. I am assuming it is some sort of screw in affair that maybe allows the use of a 2 inch filter.

Alan.

Oh, thats a 28mm Baader Fine Tuning Ring. It does just what you suggest - allows the use of a 2" filter. The 14mm Fine Tuning Ring does not quite allow to filter to clear the 1.25" barrel assembly. Of course Tele Vue do their own 2" extensions for £25 but the Baader ring does the same job, is nicely finished and costs £14 new or somewhat less used. I have them on my 6mm, 8mm and 13mm Ethos.

They also mean that all my eyepieces from 31mm to 6mm can go straight into a 2" focuser so no messing with adapters.

[Moonshane]

looks interesting John.

is the skirt threaded for 1.25" filters as well as 2"?

[John]

looks interesting John.

is the skirt threaded for 1.25" filters as well as 2"?

No. The 2" skirt is threaded just for 2" filters. It uses the 1.25" thread in the smaller barrel to thread itself on to the eyepiece. It's a clever idea but I think Tele Vue use the same approach with the 2" skirts on their Ethos SX eyepieces.

[Moonshane]

cheers John

I think they missed a trick there as it may have suited some people with just 1.25" narrowband filters

[John]

cheers John

I think they missed a trick there as it may have suited some people with just 1.25" narrowband filters

People like me ! - my Lumincon H-Beta is 1.25".