William optics swan 40mm reassembly

[Sponcom]

I wonder if anyone can help with reassembling a WO Swan 2" 40mm eyepiece.

I purchased this from SGL and the previous owner had taken it apart and cleaned it. However when I tested he eyepiece upon receipt it was clearly not right and I suspect it hadn't been reassambled properly.

I have dismantled the eyepiece and found a cross sectional cutaway diagram on the WO web site but the lenses look nothing like the lenses in the actual eyepiece. Has anyone had one of these apart and could tell me the order of the four lenses?

Any help much appreciated.

Thanks

Paul

[John]

...I have dismantled the eyepiece and found a cross sectional cutaway diagram on the WO web site but the lenses look nothing like the lenses in the actual eyepiece. Has anyone had one of these apart and could tell me the order of the four lenses?...

I think the WO Swan's have 5 lens elements

If one is missing that might be the source of your problems.

[Doc]

Hi Paul is this helpful. It's a 33 SWAN but it might help. I also thought they were 5 elements, but is the middle one cemented together so in your eyes looks like four.

[John]

..I also thought they were 5 elements, but is the middle one cemented together so in your eyes looks like four.

Good point Doc !

4 physical lumps of glass.

[Sponcom]

Thanks for the replies.

Mick - there are 4 elements (lumps of glass) and I found the cross section of the 40mm showing 4 elements. It's different to the 33mm. However the shapes of the lenses do not look anything like the cross sectional diagram so I cannot match them up to the glass.

[John]

This is from William Optics own web site:

http://www.williamoptics.com/eyepiecesDCL/images/swan40_structure.jpg

If that's not accurate then I'm stumped - you could try e.mailing William Optics direct and see what they say - they do respond I believe.

[Astro_Baby]

eeek thats not godo - did the seller state he had taken it to bits and that it was problematic.

[brantuk]

The kids had covered it in jam or peanut butter or something - so he cleaned it up and sold on stating that he'd taken it to bits and cleaned it.

[Sponcom]

The seller did mention that he had dismantled it and cleaned it but the view through it was so bad at Salisbury star party it was clear it hadn't been assembled correctly.

I am stumped too as the elements in the 40mm look nothing like the elements in mine.

Best I email them I think.

Thanks all.

[Live_Steam_Mad]

Hi, did you get this sorted out and get the eyepiece fixed? I am interested in this eyepiece as it offers the 2nd widest true field of view in any 2" eyepiece (the widest being the Vixen 42mm LVW but the Vixen's stated Eye Relief is less than the 40mm SWAN, at 20mm, like my TeleVue 8mm Radian also with it's 20mm stated ER where I keep bumping my glasses into the top of the ep even after I have removed the rubber eyeguard, when I want to see all of the field, and also the Vixen is 300 GBP!) since it offers 40mm FL at 72 degrees AFOV.

It seems there may be 3 versions of this eyepiece, one which was older and was 70 degrees AFOV, and of the older design there may be 2 different variants (as you mentioned seeing as the lens elements seemed to be different on yours) in addition to the newer 72 degree version?

I am interested in the design and construction of the William Optics 40mm SWAN (all 3? versions!), not just the views it produces. I am looking to use it with my C11. The design Eye Relief on the eyepiece is 28mm for all versions but I have read that the actual ER on the older 70 degree AFOV version was 23mm, where I read that it had "barely adequate eye relief" for glasses use (I wear spectacles for severe Astigmatism). I am wondering what the actual ER is on the new 72 degree version if anyone has one of the newer ones? Also wondering if this ep is Dioptrx compatible at all?

Best Regards,

Alistair G.

[Live_Steam_Mad]

Also I forgot to ask, has the WO 40mm SWAN got a sharp black field edge (sharp black circle) or has it instead got a rather blurred field edge?  I think I read that if the barrel in an eyepiece acts as the field stop then it produces a blurred field edge?  Also, is it possible to remove the rubber eyeguard on the this ep and have you ever done so?

I remove the rubber eyeguard e.g. on my 8mm Radian as I view using glasses and I gain a little bit of extra eye relief when I do that, and stop my glasses getting smears on them due to rubbing on the finger grease covered rubber eye guard. However even using the 8mm Radian without the rubber eyeguard at all I still end up bumping into it a little in order to be able to see the whole of the field of view at once with my glasses on even though it has 20mm of stated ER. Hence the reason I wanted the WO ep with it's supposedly higher ER. If anyone has one of these 40mm SWAN's and some reading or other glasses, can you tell me whether you can see the whole of the field of view at once comfortably without bumping into the ep, with glasses on ?

My Skywatcher 28mm Kellner was perfect in this regard. Comfortable ER for glasses use, no blackouts or Spherical Aberration of the Exit Pupil as it's known, no bumping into the ep with glasses on, I could see the whole FOV easily at once, sharp black field edge, and plenty (56 degrees) AFOV for my taste. Just wish they did a 52mm version with the same characteristics!

Best Regards,

Alistair G.