Hi All,
Winter is a great time for me to continue researching early Celestron eyepieces. One of the techniques I use for dating their production is the presence of a Japan Telescopes Inspection Institute (JTII) sticker.
I do need some help. I've included a photograph of a progression of such stickers from eyepieces in my collection. I'd appreciate any help you could provide in determining the time frame that eash was used. If you have any equipment with these (or similar) stickers and you know when it was first purchased, your info will help me narrow when each style of sticker was used.
Here's some info about the picture...
The left most eyepiece is a Celestron Circle-T 6mm Ortho from the early to mid 1960s. It sports a gold sticker with PASSED in red and the JTII moniker spelled out in blue on two lines beneath.
It gets a little more interesting...
The center eyepiece is a Celestron Circle-M Kellner dating from the late 1960's or early 1970's. It sports a circular yellow JTII sticker with blue lettering. As a side note, I am fairly certain that the Circle-M eyepieces were not made by Mizar as some other discussion threads have suggested (I can explain why in another post if anyone is interested).
Even more interesting...
The right eyepiece is a very early (how early, I don't know - yet) Celestron Silver Top Plossl. It sports a round green JTII sticker with gray lettering in the same format as the yellow one in the center.
I've been told that the practice of using JTII was phased out sometime in the mid-1970s. If I can get a number of posts regarding equipment purchased and the type of sticker on it, I should be able to narrow when each style of sticker was used.
Thanks in advance!
Blake
Winter is a great time for me to continue researching early Celestron eyepieces. One of the techniques I use for dating their production is the presence of a Japan Telescopes Inspection Institute (JTII) sticker.
I do need some help. I've included a photograph of a progression of such stickers from eyepieces in my collection. I'd appreciate any help you could provide in determining the time frame that eash was used. If you have any equipment with these (or similar) stickers and you know when it was first purchased, your info will help me narrow when each style of sticker was used.
Here's some info about the picture...
The left most eyepiece is a Celestron Circle-T 6mm Ortho from the early to mid 1960s. It sports a gold sticker with PASSED in red and the JTII moniker spelled out in blue on two lines beneath.
It gets a little more interesting...
The center eyepiece is a Celestron Circle-M Kellner dating from the late 1960's or early 1970's. It sports a circular yellow JTII sticker with blue lettering. As a side note, I am fairly certain that the Circle-M eyepieces were not made by Mizar as some other discussion threads have suggested (I can explain why in another post if anyone is interested).
Even more interesting...
The right eyepiece is a very early (how early, I don't know - yet) Celestron Silver Top Plossl. It sports a round green JTII sticker with gray lettering in the same format as the yellow one in the center.
I've been told that the practice of using JTII was phased out sometime in the mid-1970s. If I can get a number of posts regarding equipment purchased and the type of sticker on it, I should be able to narrow when each style of sticker was used.
Thanks in advance!
Blake
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