Some discussion of Masuuyama and clone eyepieces

[notFritzArgelander]

I think Synta describe these sometimes as 'five element Plossls', which is a bit weird. I was using the 7mm (in a Vixen 2x Barlow) to view Mars recently. Predominantly because its filter thread is compatible with my Lumicon #11 filter and my 7mm Fujiyama orthoscopic isn't. I thought it held its own against the ortho'. Not sure if they're a similar design to the 'Planetary HR' range.

The phrase "five element Plossl" is not just weird, it's wrong. It's a "marketing tense" phrase, true only because it makes sales.

The "five element Plossl" is based on the Zeiss Astroplan design and is often copied under Celestron Ultima, Orion Ultrascopic, Parks Gold and Masuyama.

The Planetary HR range has 6 lenses and is a different design.

[Shorty Barlow]

Probably. I haven't taken any of them apart to see.



I'm fairly sure my 15mm Antares 'Plossl' is a Masuyama clone. Not sure about the Baader Eudiascopic.

[notFritzArgelander]

Probably. I haven't taken any of them apart to see.

I'm fairly sure my 15mm Antares 'Plossl' is a Masuyama clone. Not sure about the Baader Eudiascopic.

The better Antares Plossls are part of the Masuyama cloning of the Zeiss Astroplanokular. There are credible rumors that the Baader and Zeiss Eudiascopic are identical to the Astroplanokular. I've not used them though so can neither confirm nor deny.

[Shorty Barlow]

Probably. I haven't taken any of them apart to see.

I'm fairly sure my 15mm Antares 'Plossl' is a Masuyama clone. Not sure about the Baader Eudiascopic.

The better Antares Plossls are part of the Masuyama cloning of the Zeiss Astroplanokular. There are credible rumors that the Baader and Zeiss Eudiascopic are identical to the Astroplanokular. I've not used them though so can neither confirm nor deny.

The 10mm Eudiascopic seems to have a similar FOV to the Antares, around 44~45 degrees. So it stands a good chance. I think the Eudiascopics are (or were) manufactured by Ohi Optical Manufacturing Co,. Ltd (Oi Kouki Co., Ltd.). As were most of the orthoscopics I own probably.



I sent an email to Sherlock Holmes but he's indisposed at the moment. Mycroft, though, is fairly certain that the factory is located here. He could be right, he does work for MI6 in his spare time (apparently).

[Shorty Barlow]

The Planetary HR range has 6 lenses and is a different design.

They may have six lenses, but some of the longer focal lengths have no barrel (possibly Smyth lens/Barlow) element. So, are they a five lens design? The UWA's and HR's are remarkably similar in performance and have identical FOV's of 58 degrees.

[notFritzArgelander]

The Planetary HR range has 6 lenses and is a different design.

They may have six lenses, but some of the longer focal lengths have no barrel (possibly Smyth lens/Barlow) element. So, are they a five lens design? The UWA's and HR's are remarkably similar in performance and have identical FOV's of 58 degrees.

Six versus five lenses is sufficient to establish the designs as different. You could always dissect a couple to see for sure.

[Shorty Barlow]

The Planetary HR range has 6 lenses and is a different design.

They may have six lenses, but some of the longer focal lengths have no barrel (possibly Smyth lens/Barlow) element. So, are they a five lens design? The UWA's and HR's are remarkably similar in performance and have identical FOV's of 58 degrees.

Six versus five lenses is sufficient to establish the designs as different. You could always dissect a couple to see for sure.

I may have a borked one of each somewhere. I'll see if I can find them out lol. If the UWA's have five lenses, does that include the Smyth? I was told that there was once a 25mm UWA made, apparently an order misunderstanding by the OEM, and it was very good as an eyepiece.

[notFritzArgelander]

They may have six lenses, but some of the longer focal lengths have no barrel (possibly Smyth lens/Barlow) element. So, are they a five lens design? The UWA's and HR's are remarkably similar in performance and have identical FOV's of 58 degrees.

Six versus five lenses is sufficient to establish the designs as different. You could always dissect a couple to see for sure.

I may have a borked one of each somewhere. I'll see if I can find them out lol. If the UWA's have five lenses, does that include the Smyth? I was told that there was once a 25mm UWA made, apparently an order misunderstanding by the OEM, and it was very good as an eyepiece.

It's customary to count the Smyth lens in the total. They are usually a doublet so a Smyth adds 2 to the total count.

It’s maybe amusing to note that Smyth’s main purpose was to flatten the field the Barlow lens function was a side effect.

[Shorty Barlow]

Six versus five lenses is sufficient to establish the designs as different. You could always dissect a couple to see for sure.

I may have a borked one of each somewhere. I'll see if I can find them out lol. If the UWA's have five lenses, does that include the Smyth? I was told that there was once a 25mm UWA made, apparently an order misunderstanding by the OEM, and it was very good as an eyepiece.

It's customary to count the Smyth lens in the total. They are usually a doublet so a Smyth adds 2 to the total count.

It’s maybe amusing to note that Smyth’s main purpose was to flatten the field the Barlow lens function was a side effect.

Well all I can tell you about the UWA's is what Sky-Watcher (Synta) claim. I think the 'five element' legend is written on the box they come supplied in. I'm fairly convinced they were originally made by Barsta. I also believe some focal lengths were bundled with a couple of mid-level Sky-Watcher refractors at one time. TBH I always though they were pretty good and rivalled my ortho's for contrast. Definitely decent for under forty quid. I still have, and occasionally use, the 6mm, 7mm and 9mm.

[Lady Fraktor]

I'm fairly sure my 15mm Antares 'Plossl' is a Masuyama clone

Antares made regular Plossl and Elite Plossl at the same time.
If yours gives a clean view with telescopes faster than f/7 then it is most likely a regular Plossl.
The Masuyama design works best at f/7 or slower.

Is there any astro eyepiece or accessory you do not think was made by Barsta??

[Shorty Barlow]

I'm fairly sure my 15mm Antares 'Plossl' is a Masuyama clone

Antares made regular Plossl and Elite Plossl at the same time.
If yours gives a clean view with telescopes faster than f/7 then it is most likely a regular Plossl.
The Masuyama design works best at f/7 or slower.

Is there any astro eyepiece or accessory you do not think was made by Barsta??

The Antares says MC on it and I was told it was a Masuyama clone by the retailer who sold it to me. It has around a 44 degree FOV. There's loads not made by Barsta.

[notFritzArgelander]

I'm fairly sure my 15mm Antares 'Plossl' is a Masuyama clone

Antares made regular Plossl and Elite Plossl at the same time.
If yours gives a clean view with telescopes faster than f/7 then it is most likely a regular Plossl.
The Masuyama design works best at f/7 or slower.

Is there any astro eyepiece or accessory you do not think was made by Barsta??

The Antares says MC on it and I was told it was a Masuyama clone by the retailer who sold it to me. It has around a 44 degree FOV. There's loads of shite not made by Barsta. I'm not talking out of my clacker.

Usually MC means multi coated as opposed to FMC for fully multi coated. I've never heard of MC meaning Masuyama clone.

[Shorty Barlow]

Antares made regular Plossl and Elite Plossl at the same time.
If yours gives a clean view with telescopes faster than f/7 then it is most likely a regular Plossl.
The Masuyama design works best at f/7 or slower.

Is there any astro eyepiece or accessory you do not think was made by Barsta??

The Antares says MC on it and I was told it was a Masuyama clone by the retailer who sold it to me. It has around a 44 degree FOV. There's loads not made by Barsta.

Usually MC means multi coated as opposed to FMC for fully multi coated. I've never heard of MC meaning Masuyama clone.

I very much doubt it actually means 'Masuyama clone' and assumed it was coincidental, but I've seen other 'Plossls' like mine with it written on. I've not seen it written on most Antares standard Plossls. I only use it for lunar/planetary anyway. It is very orthoscopic-like in contrast and the FOV is basically the same as the Eudiascopic, ruling it out as a standard. It's Japanese and very probably made by Ohi (Masuyama). Besides, I know the retailer I bought it from well, I doubt he was lying. I have a sneaking suspicion he's a Bolton Wanderers fan though.

[Lady Fraktor]

The Antares says MC on it and I was told it was a Masuyama clone by the retailer who sold it to me. It has around a 44 degree FOV.

My Elite as well as Plossl says MC on them, (which stands for multicoated not Masuyama clone) the only way to check which version you have is by checking its performance.
Just some information for others that may come across them.

[Shorty Barlow]

The Antares says MC on it and I was told it was a Masuyama clone by the retailer who sold it to me. It has around a 44 degree FOV.

My Elite as well as Plossl says MC on them, (which stands for multicoated not Masuyama clone) the only way to check which version you have is by checking its performance.
Just some information for others that may come across them.

It's still a Masuyama clone, whatever you say.

[Lady Fraktor]

You do not need to be defensive, no where have I said it is not.
I provided information for others to tell the difference between the two types as they outwardly look identical.

[turboscrew]

It just looks like Masuyama doesn't make 15mm eyepieces. The closest is 16 mm.

[Lady Fraktor]

The original discontinued Masuyama eyepieces were available as 1.25" and did include a 15mm

[turboscrew]

The original discontinued Masuyama eyepieces were available as 1.25" and did include a 15mm

Hmm, so it seems. I tried to search, but didn't find. Not even on Ohi Optical's pages.

[Jones]

My supply of masuyama made eyepieces are 6 and 4mm Hutechs, Tak abbe 6mm and this strange Kasai 5mm 5 element. Agena in USA sold various Kasai for a couple years, but everyone dismissed it because it was in a Ultima housing. But one look and WOW! That is how you can tell a masuyama made lens from ordinary lenses.