Spencer planoscopic ocular circa 1924? EDIT: NO

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J_WISC
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Spencer planoscopic ocular circa 1924? EDIT: NO

#1 Post by J_WISC » Tue Feb 14, 2023 3:24 am

Hello.

The eyepieces in the photo were with a 1916 Spencer monocular microscope. Despite 4x and 5x magnification (not listed in 1924 catalog), and no indication of manufacturer, are the eyepieces likely Spencer planoscopic? The internal structure resembles the illustration for catalog nos.175-180.
eye single 4x and 5x side smaller.jpg
eye single 4x and 5x side smaller.jpg (42.92 KiB) Viewed 2003 times
eye single 4x and 5x top smaller.jpg
eye single 4x and 5x top smaller.jpg (43.63 KiB) Viewed 2003 times
eye single 4x and 5x bottom smaller.jpg
eye single 4x and 5x bottom smaller.jpg (44.17 KiB) Viewed 2003 times
new planoscopic ocular - 1924.jpg
new planoscopic ocular - 1924.jpg (232.3 KiB) Viewed 2003 times
There were a similar 6x Leitz, and two similar 10x B&L oculars with the microscope as well.

Thank you.
Last edited by J_WISC on Wed Feb 15, 2023 5:05 am, edited 1 time in total.

apochronaut
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Re: Spencer planoscopic ocular circa 1924?

#2 Post by apochronaut » Tue Feb 14, 2023 3:54 am

The 5X looks to be a catalogue # 136 Spencer 5X Huyghens. I don't think the 4X is Spencer. Spencer did not mark their oculars with a brand but the knurling around the perimeter of the eyelens mount is quite distinctive.
Planoscopic were marked as such on the eyelens bezel. planoscopic 10X for instance. Note that they have a smaller eyelens, that of the 10X is only about 1/4" in diameter but it is a doublet and I have not seen a 5X planoscopic and certainly not a 4X. 5,,6,8,10,12,15 and 20X were the common increments of eyepieces at Spencer with 4X and 30X rarely. The 30X was a compens only and was probably used only in rare instances with the 10X and 20X apochromats in order to preserve their longer working distance at the expense of eye relief. There were 2.5X and 3X projection eyepieces for photography etc.
Last edited by apochronaut on Wed Feb 15, 2023 7:20 pm, edited 1 time in total.

apochronaut
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Re: Spencer planoscopic ocular circa 1924?

#3 Post by apochronaut » Tue Feb 14, 2023 5:30 pm

Here is a couple of group shots of most of the Spencer eyepieces used up until about 1955 for the 160mm system, one is likely to encounter.

Picture 1) are the more common Huyghens types with a Ramsden and early W.F. type included. The design of the eyepieces was changed in the late 20's from a conventional flat eyelens bezel design to a more peaked cone design, similar to that used by Meopta and in some instances Leitz. However the optics stayed pretty much the same.
Left to right back row is the design up to 1929, except the focusing eyepiece which persisted until the infinity era. The maker and type of eyepiece were not marked on them, just the magnification engraved on the top. The knurling around the edge of the eyelens bezel of that era of Spencer eyepieces is fine and unique.
3X Projection eyepiece, 6X Huyghens, 10X Huyghens, 10X Huyghens focusing type to take a reticle. There were also 4X,5X,15X and 20X, which looked just like longer or shorter versions of the middle 2.
Left to right front row. There was still no branding and the magnification engraving has been moved to the barrel. 5X Huyghens, 6X Huyghens, 8X Huyghens, 8X Ramsden, 10X Huyghens, 10X W.F. (marked on the barrel). There were also 15 and 20X Huyghens, 10,15 and 20X Ramsden and 6 and 15X W.F. The Ramsden pictured has nothing marked on the barrel but usually the word Ramsden is stamped on the barrel as well as the magnification. The 8X Ramsden pair I have must have been either very early ones or a custom production.
In all cases if there is a serial# it is to designate a custom tested and matched pair and there would have originally been two with the same serial#.

Picture 2). Spencer marked eyepieces with optical formulas other than Huyghens on the top bezel and as mentioned in the csse of Ramsden, on the side of the barrel. Compens and planoscopic designs maintained a flat top profile from their inception until there was a design change around 1955.
Left to right back row. 5X compens, 10X compens hi-eyepoint, 10X compens , 15X compens, 20X compens, 30X compens.
Left to right middle row. 10X planoscopic, 15X planoscopic, 20X planoscopic.
Front row. After the series #5 was discontinued, AO transferred the apochromat concept to the Apostar, a variation on the series 4. The apochrnomat objectives were redesigned into brushed chrome on brass barrels and the compens eyepieces received a more modern look too but more importantly there was a chsnge in the compensation. The 10X compens in the front is one of those for the series 4 apostar.

Not shown in the pictures is a 2.5X compens, 5X planoscopic and the series 4 15X compens.
Attachments
1676395195810.jpg
1676395195810.jpg (75.95 KiB) Viewed 1958 times
1676395144842.jpg
1676395144842.jpg (111.11 KiB) Viewed 1958 times

J_WISC
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Re: Spencer planoscopic ocular circa 1924?

#4 Post by J_WISC » Wed Feb 15, 2023 12:08 am

apochronaut wrote:
Tue Feb 14, 2023 3:54 am
The 5X looks to be a catalogue # 136 Spencer 5X Huyghens.
Is the ocular on the right, catalog illustrated cross section, plano-convex field lens, the Huyghens? If so, bad graphic design or layout for the novice flipping through their catalog.

apochronaut
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Re: Spencer planoscopic ocular circa 1924?

#5 Post by apochronaut » Wed Feb 15, 2023 1:34 am

So, the two oculars pictured in the upper section they designate as examples of Huyghens by virtue of the catalogue #'s below. ; 134-144. The two schematic drawings in the lower section are designated as examples of planoscopic eyepieces by virtue of the cat. #'s 175-180 below. The catalogue #'s exhibit the range, not the specific items pictured.
Huyghens are always two plano/convex singlet lenses. The planoscopic oculars vary and are either plano/convex doublet x plano/convex singlet as the 10X is or plano/convex doublet x bi-convex singlet as the 15 and 20X are. Presumably the 5X would be plano/convex doublet x plano/convex singlet.
Those two schematic illustrations appear to be 15X left and 10X right. They are quite accurate. The 10X planoscopic plano/convex field lens is indeed forward of the field stop and the 15X bi-convex field lens behind the field stop.
Last edited by apochronaut on Wed Feb 15, 2023 1:33 pm, edited 1 time in total.

J_WISC
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Re: Spencer planoscopic ocular circa 1924?

#6 Post by J_WISC » Wed Feb 15, 2023 2:29 am

I see! Gosh I feel foolish. I interpreted the catalog numbers as labels for two columns, an example of products 134-144 on the left and an example of products 175-180 on the right. Thank you.

apochronaut
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Re: Spencer planoscopic ocular circa 1924?

#7 Post by apochronaut » Wed Feb 15, 2023 2:59 am

Material in a lot of catalogues is very easy to misinterpret. I had the benefit of having actual eyepieces to refer to. AO and Spencer have a history of reusing illustrations and cat.#'s, so their printed literature has more than a few times been difficult for me.

J_WISC
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Re: Spencer planoscopic ocular circa 1924?

#8 Post by J_WISC » Wed Feb 15, 2023 3:19 am

Are the extended caps, for lack of a better word, characteristic of Spencer Huygen wide field oculars. Below are two sets which were with a Spencer dissecting scope, circa 1945. Are the oculars interchangeable from dissecting scope to compound microscope? I realize I’ll still see something, but what about quality?

Thank you for your help. Your photos of eyepieces are just what I was hoping to find somewhere on the internet.
17E5C6BC-620B-42E6-ACC0-A91E8EC70667.jpeg
17E5C6BC-620B-42E6-ACC0-A91E8EC70667.jpeg (185.54 KiB) Viewed 1894 times
630A7FCE-8869-4782-A36F-3ED1CB8A7403.jpeg
630A7FCE-8869-4782-A36F-3ED1CB8A7403.jpeg (252.6 KiB) Viewed 1894 times
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B2434D9C-39EC-4B7A-91AA-B6CA945AAE52.jpeg (210.61 KiB) Viewed 1894 times
104C6E49-82BA-442C-9EBD-88C862521060.jpeg
104C6E49-82BA-442C-9EBD-88C862521060.jpeg (196.84 KiB) Viewed 1894 times

apochronaut
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Re: Spencer planoscopic ocular circa 1924?

#9 Post by apochronaut » Wed Feb 15, 2023 3:30 am

Those have poor off axis correction when used with achromat compound microscope objectives in my experience. I didn't try them out extensively but with the 10X and I think 44X I did try them with, they generated a lot of ca. They were catalogued exclusively for use with stereo microscopes and work well in that role giving well corrected quite wide flat fields with the series 25 through 28 stereos.

J_WISC
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Re: Spencer planoscopic ocular circa 1924?

#10 Post by J_WISC » Wed Feb 15, 2023 5:04 am

Well, that leaves me with two pairs of eyepieces for my Spencer #5. A pair of B&L 10x and pair of Spencer 6x. I was not impressed by the B&L.

C349BCBC-339E-4A0C-AFBB-E05F708D9A9E.jpeg
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A01E25BC-EE34-4046-A8D7-8BDC5FE2FE79.jpeg (191.45 KiB) Viewed 1879 times
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C4CEEDE2-D303-4F09-809C-4FA2BC7A9770.jpeg (257.03 KiB) Viewed 1879 times
Someone — I apologize for not recalling name — recommended a specific Spencer and a specific Olympus set of eyepieces. Are there other suggestions for proper eyepieces for a Spencer #5?

apochronaut
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Re: Spencer planoscopic ocular circa 1924? EDIT: NO

#11 Post by apochronaut » Wed Feb 15, 2023 1:30 pm

That depends on the objectives, not the microscope. The B & L 10X Huyghens , which those eyepieces are, should work fine enough with Spencer achromats but not apochromats. The same is true for the Spencer Huyghens eyepieces. Achromat objective and huyghen eyepiece combinations will always have some optical defects ; residual lateral ca, some sa, curvature of field, maybe some astigmatism and coma. That's just the nature of that sort of optical system, which are and were economical. Everybody used that combination for a reason and even today simple achromat systems flood the market.
That is also why fluorite and apochromat optical combinations exist. With the older apochromat designs and it is hard to pick an exact time frame that covers older because the different manufacturers moved at different paces but with Spencer it was pre 1963, there should be little of any of those distortions and aberrations but only if the eyepiece carries the correct calculation to compensate for the objective's calculations. Plus the image is provided as flatter than that of an achromat. Using a Huyghens eyepiece, which lacks calculations as such, kind of negates the point of having an apochromat. If you are going to be mixing objective types, the best option is to search out planoscopic eyepieces, which are kind of in the middle ground and while improving the performance of achromats, they aren't quite fully compensating for the apochromats , nonetheless they are good. That is a good compromise that I know of. B & L Hyperplane might do as well or other eyepieces too but with older eyepiece/objective combinations, testing them is the only real way . The planoscopics I have, I use on an old binocular research stand fitted with two Spencer fluorites but there never was a low power fluorite, just achromats, so even with an achromat in the mix that combination is very good with a surprisingly flat wide field for such an old microscope. A 1.3 N.A. achromat oblique condenser too. It is a Spencer # 2, probably made in Sept. 1920.

The # 5 deserves a good set up and the best set up on the # 5 in order to take advantage of it's full potential, is either a full set of apochromats and a set of 10 and 15X compens eyepieces, or a cat.#106 3.5X achromat plus 3 apochromats and either compens or planoscopics. The #106 is an almost full length, chrome finished objective with only a 4.2mm working distance. Almost all sub 5X objectives from it's time were very short with working distances of 20mm and up. This one has field flattening optics added so it was really an early low power plan objective, working well with higher power objectives as parfocal. Unique.

It might have been me that recommended the Olympus Bi WF10X. It is a heavily compensating eyepiece. It works well enough with Spencer but better with B & L apochromats, which require a little more compensation. That is an option but they don't work well with conventional achromats.

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