5 replies to this topic

[MrsM75]

Is the Explorer Scientific 52 deg eyepiece a Plossl? It 4 lens 2 groups. Plossl it like that too.

 

And what you say about the "quality" of the image between the ES 52 deg vs ES 62 deg, beside the wider FOV.

 

Thank you.

[Ernest_SPB]

Depends from focal length.

 

3-15mm ES52 look like Plossl + negative cemented component in barrel (6 elements in 3 components)

20mm ES52 has formula 5/3 (must be negative cemented component in barrel and like reverse-Kelner in its body)

25-40mm ES52 are typical Plossl

Edited by Ernest_SPB, 21 April 2025 - 01:57 AM.

[eblanken]

Hello MrsM75,

 

Here's a link: https://en.wikipedia...ki/Simon_Plössl

 

You are going to get different answers: some will say yes . . . others will say no . . . 

 

You are correct that Plossls are two groups of two each . . . symmetrical or ortho or both ??? What glass types ??? Do you want to know the history ???

 

Perhaps JG or Don can speak to your question with some expertise . . . 

 

Best,

 

Ed

 

P.S. OK, trust Ernest (an international treasure of an expert) who posted while I typed . . .

        MrsM75 you should do well with these I think . . . 

 

        Here's a better link to the Plossl Telescope Eyepiece portion: https://en.wikipedia...2Symmetrical.22

Edited by eblanken, 21 April 2025 - 02:09 AM.

[Avgvstvs]

I'm glad that ES has chosen the field of view as their identifiers. A bit of a more of a modern take on how EP's are used rather than an 'old' optical formula. And that way they are not stuck with the one design and can change it to suit. Plenty of pure Plossl designs out there for purists.

[SeattleScott]

The 62s are five element and will struggle at the edges in fast scopes.

[MrsM75]

Depends from focal length.

 

3-15mm ES52 look like Plossl + negative cemented component in barrel (6 elements in 3 components)

20mm ES52 has formula 5/3 (must be negative cemented component in barrel and like reverse-Kelner in its body)

25-40mm ES52 are typical Plossl

 

Thank you Sir, I was lucky to get a 20mm and 10mm of the 52 deg ES, it OverStock sale for the price of $78 New (original by ES price is $119)

I was lucky because the Overstock sale end exactly at midnight April 30th. It from a no name store, not popular store at all.

 

Let hope they send me the real eyepieces and not a clone or something. It worth a try due to the $78 price New.

 

Will report back once I get it. Not sure when the Overstock price sale will be back, maybe not ever back at all due to the tariff.