9mm WO SWAN Disassembly

[Highburymark]

Mak - I wonder if the WO 9mm is similar in design to the 20mm 66 degree pair included with the WO binoviewer? I tend not to use the 20mms - prefer TV plossls and Fujiyama orthos for solar binoviewing - but have never really worked out what the WO 20mms are design-wise

[Mak the Night]

1 hour ago, Highburymark said:

Mak - I wonder if the WO 9mm is similar in design to the 20mm 66 degree pair included with the WO binoviewer? I tend not to use the 20mms - prefer TV plossls and Fujiyama orthos for solar binoviewing - but have never really worked out what the WO 20mms are design-wise

Yes, I wondered the same thing. Here's one I prepared earlier lol:

They're better than the 9mm SWAN's but I was never really super impressed with them. 

I replaced them with a couple of these.

https://www.telescopehouse.com/eyepieces/bresser-eyepieces/bresser-60-plossls/bresser-pl-20mm-60-1-25-inch.html

I lose six degrees of FOV, and I have no idea what these Bresser EP's really are, but they are sharp and bright in use.

[Louis D]

5 hours ago, Mak the Night said:

I lose six degrees of FOV, and I have no idea what these Bresser EP's really are, but they are sharp and bright in use.

They're probably a rebadging of the Meade 5000 60 degree Plossl series.  There was also a 5.5mm and a 40mm version as well.  I have the latter, and it is quite a performer in the center 30 degrees.  I'm surprised Bresser didn't reissue the whole range.

[Mak the Night]

56 minutes ago, Louis D said:

They're probably a rebadging of the Meade 5000 60 degree Plossl series.  There was also a 5.5mm and a 40mm version as well.  I have the latter, and it is quite a performer in the center 30 degrees.  I'm surprised Bresser didn't reissue the whole range.

Yes, it stands a good chance. 

I have the 5.5mm, 9mm, 14mm and a pair of 20mm. TH used to have the 5.5mm in stock, I'm pretty sure they had a 40mm as well. 

[Highburymark]

7 hours ago, Mak the Night said:

Yes, I wondered the same thing. Here's one I prepared earlier lol:

They're better than the 9mm SWAN's but I was never really super impressed with them. 

Missed that post. V interesting

[Mak the Night]

Yes, I assumed these were Erfles as everyone told me they were. It seems two convex elements combined with a third multiple element seems to be a bit of a trend. The field lens appearing to all intents and purposes to be a doublet, yet showing evidence of being a triplet, has been found in two EP's I've autopsied lol. This is most mysterious. 

[Ricochet]

The eyepieces supplied with your binoviewers aren't 5 element SWANs but 4 element WAs, which explains why the group looks like a doublet.