An AO Spencer  Objectives Reference

Using the various available manuals and catalogs it is possible to construct a reference of Cat #'s (Catalog Numbers) and Objectives that may be useful in finding objectives for your AO Spencer microscope.   


Description Example Models Time-frame TL and parfocal distance
Metallurgical Scopes   Any era Infinity TL
Black Scopes Series 33, 35, etc.   1920s - 1956 160mm TL, 34mm parfocal*
The Blue-Gray  Scopes Series 1, 2, 4.   1956 until 1961 160mm TL, 34mm parfocal
The Gray Scopes, and Gray & White Scopes Series 10, 20, 110, 120, etc.   1961 to 1985 Infinity, 34mm parfocal 
The White Scopes AO-Reichert, Reichert, Leica, Series 310, 410, etc.   From 1985 Infinity, 45mm parfocal

The rules for objectives:

1.  You cannot put infinity corrected lenses on a 160mm TL scope, nor can you put 160mm TL objectives on an infinity corrected scope . . . Yes, you'll get an image sometimes . . . but not a very good one.
2.  It is a pain to mix 34mm and 45mm parfocal objectives on the same nosepiece -- stick with one or the other -- or prepare to be frustrated and possibly to crunch an objective or two against the slide and coverglass  :-)

Eyepieces, on the other hand, are quite forgiving can be used interchangeably on 160mm TL and Infinity corrected scopes with good results.*  

*Note: The 'purist' in me wants to note that the very best, optimum results will be obtained by using the eyepieces specifically  made for each objective set (e.g.  a Cat# 146 10x eyepiece on a 160mm TL Series 2 scope, a Cat# 176 10X eyepiece on an infinitely corrected Series 10 scope, etc.) -- but the 'practical side' of me says it really, truly doesn't make a heck of a lot of difference -- use what you have.  But if you are wondering what the differences might be between different brands of eyepieces, Mervhob of Yahoo's Microscope Group has furnished the useful information below (also see Mikrofibel page 55) :

Table of Eyepiece Distance to First Image

Maker

From Top of Body Tube (mm)

From Objective Shoulder (mm)

Mechanical  Tube Length

Zeiss-Winkel

5

155

160

Zeiss (Old pre 1948)

15

145

160

Zeiss (Oberkochen)

10 (old 13)

150 (old 147)

160

Reichert

13

147

160

Reichert (metal.)

13

177

190

Leitz

18

152

170

Leitz (metallurgical)

18

197

215

Leitz (Ultropak)

18

167

185

A. O. Spencer

11.3

148.7

160

Bausch & Lomb

11

149

160

B & L (metallurgical)

11

204

215

C. Baker

0

160

160

C. T. S.

20

140

160

Beck

10

150

160

Beck (metallurgical)

10

190

200

Wild Heerbrugg 9 151 160
PZO 10 150 160
Olympus (Tokyo) 16 144 160

You can see that B&L (Bausch & Lomb) eyepiece are very close to the same specifications as AO eyepieces.  It is quite common to find B&L eyepieces on AO scopes and, probably, vice-versa.  Amazingly, you'll often find B&L objectives on AO scopes, without an shims, even though their parfocal distance is 35.6mm vs. the 34mm distance for AO Objectives.

OK, Here is a list of the AO and Spencer Objectives 'known' to me from either experience, or from the AO Spencer Literature (i.e. a catalog or a manual).  (Note: You can select the whole list, top to bottom, and past it into Excel to create a spreadsheet that can be sorted on any column if you'd like)

Sources:

#1 = 110 Objectives Catalog #6 = AO 60 Manual #11 = Series 2 & 4 Phase Catalog #16 - MetalStar 2200 manual
#2  = Series 10 Phase Catalogs #7 = AO 120 Manual #12 = Series 10 Phase Manual #17 - Seen on eBay
#3 = Epi Lume Catalog #8 = 1969 Series 10 Manual #13 = Series 15 & 35 Catalog #18 -- AO PolStar Brochure
#4 = AO Starlight Catalog #9 = eBay or have used one #14 = Series 15 & 35 Phase Catalog  
#5 = BioStar Inverted Catalog #10 = Series 2 & 4 Catalog #15 = DN50, DN60 Dual View Manual  

 Note: A 'C' at the beginning of the Cat#, at least in the Series 15 and 35 era (1930's and 40's), meant 'C'oated.  For example, you could order either a Cat# 115 uncoated 43x objective, or a Cat# C115 coated (Americote) objective.  A 'K' at the beginning of a Cat# designated a 'special order' item.

Cat # Power Correction N.A. W.D (mm) T.L (mm) Parfocal (mm) Comments Source
B42504 10x Achro 0.25   160? 34?   9
B44762 97x Achro 1.25   160 34?   9
B62717 43x Achro 0.66 160 34   9
(C)101 2x Achro 0.08 52.5 160      13
(C)102 3x Achro 0.08 35.2 160     13
(C)104 4x Achro 0.10 21.0 160     13
C105 3.5x Achro 0.09 25.4 160 34   10
(C)106 3.4x Achro 0.08 37.0       13
C107 5x Achro 0.20 20 160 34   10
C109 10x Achro 0.25 6.8 160 34   10
C110 10x, 4.2x Achro 0.25, 0.10 6.8 160 34 Separable Objective 10
C112 20x Achro 0.50 1.3  160 34   10
C115 43x Achro 0.66 0.73 160 34   10
(C)118 43x Achro?  0.85 0.18 160     13
(C)122 57x Achro?  0.85 0.12 160      13
C125 50x Oil Achro 0.95 0.37 160 34   10
C127 97x Oil Achro 1.25 0.12 160 34   10
C150 10x Apo  0.30 5.2 160 34   10
C152 20x Apo  0.60 0.65 160 34   10
C154 43x Apo  0.95 0.15 160 34 With Correction Collar 10
C158 90x Apo  1.30 0.08 160 34   10
C159 90x Apo  1.40 0.05 160 34   10
C1279 10x Achro         Short mount objective 16
C1283 20x Achro         Short mount objective 16
C1289 40x Achro         Short mount objective 16
C1292 97x Oil Achro  1.25 0.13 160 34 With Iris 10
C1294 95X Achro         Short mount objective 16
C47121 43x Achro  0.66   160 34   9
C61546 43x Phase Achro 0.66   160 34 Bright - M  9
C71789 43x Achro 0.66   160 34    9
C73486 10x Achro 0.25   160 34    9
C73540 10x Achro 02.5 160 34    9
K2075 6.5x Air Spaced       Inf. 34 Air Spaced Objectives for Laser Apps.. Series 3000 scopes 1
K2259 6.5x Air Spaced     Inf. 34 Air Spaced Objectives for Laser Apps., Series 3000 scopes 1
K1610 10x Air Spaced     Inf. 34 Air Spaced Objectives for Laser Apps., Series 3000 scopes 1
K2246 10x Air Spaced     Inf. 34 Air Spaced Objectives for Laser Apps., Series 3000 scopes 1
103 4x Achro 0.10 17.5 Inf. 34 Student Objectives 6
113 10x Achro 0.25 6.9 Inf. 34 Student Objectives 6
114 43x Achro 0.55 0.6 Inf. 34 Student Objectives 6
130 4x Std. Achro  0.10 17.5 Inf. 34 Student Objectives 1
131 10x Std. Achro  0.25 6.9 Inf. 34 Student Objectives 1
132 43x Std. Achro  0.55 0.6 Inf. 34 Student Objectives 1
1014 100x Oil Adv. Plan Achro 1.25 0.1 Inf. 34 With Iris 1
1016 50x Oil Adv. Plan Achro 0.80 0.3 Inf. 34 With Iris 1
1017 4x Plan Achro  0.12 7.22 Inf. 34   5
1017S 4x Adv. Plan Achro 0.12   Inf. 34 Strain Free -- for Pol. Work 1, 18
1019 10x Plan Achro 0.25 9.1 Inf. 34   4
1019S 10x Plan Achro 0.25   Inf   Strain Free -- for Pol. Work 18
1021 10x Adv. Plan Achro 0.25 4.3 Inf. 34   7
1021S 10x Adv. Plan Achro     Inf. 34 Strain Free -- for Pol. Work 1
1022 20x Adv. Plan Achro 0.50 1.4 Inf. 34    1
1022S 20x Adv. Plan Achro 0.50 1.4 Inf. 34 Strain Free -- for Pol. Work 1, 18
1023 40x Achro 0.66 0.5 Inf. 34   8
1023 40x Plan Achro.     Inf. 34   4
1024 100x Plan Achro  1.25 0.1 Inf. 34   5
1026 10x Adv. Achro 0.25 9.1 Inf. 34 Industrial, Series 3000, 2560 1
1026 50x Achro 0.85 0.3 Inf. 34 With Iris 8
1027 100x Achro 1.25 0.1 Inf. 34 With Iris 8
1028 2.5x Adv. Plan Achro 0.07 9.2 Inf. 34   1
1028S 2.5x Adv. Plan Achro 0.07 9.2 Inf. 34 Strain Free -- for Pol. Work 1
1029* 50x Achro 0.85 0.3 Inf. 34   8
1029* 100x Plan Achro  1.25 0.1 Inf. 34   9
1029S 100x Plan Achro 1.25       Strain Free -- for Pol. Work 18
1075 4x Achro 0.12 7.2 Inf. 34   8
1076 10x Achro 0.25 9.1 Inf. 34   8
1077 20x Achro 0.50 0.80 Inf. 34   8
1078 45x Achro 0.66 0.7?   Inf. 34    17
1079 100x Achro 1.25 0.1 Inf. 34   8
1079 100x Oil Adv. Achro 1.25 0.1 Inf. 34    1
1109 10x Achro.       Inf  34    15
1116 45x Achro. 0.66 0.7 Inf. 34   8
1116 45x Adv. Achro 0.66 0.7 Inf. 34 Long W.D. good for Hemacytometer 1
1126 4x Adv. Plan Achro 0.12 7.2 Inf. 34    1
1127 10x Adv. Plan Achro 0.25 4.3 Inf. 34    1
1128 40x Adv. Plan Achro 0.66 0.5 Inf. 34 Longer W.D. good for Hemacytometer 1
1129 100x Oil Adv. Plan Achro 1.25 0.1 Inf. 34    1
1211 10x Phase Plan Achro 0.25 9.1 Inf. 34  Dark Phase 1
1212 20x Phase Plan Achro 0.50 1.4 Inf. 34  Dark Phase 1
1213 40x Phase Plan Achro 0.66 0.5 Inf. 34  Dark Phase 1
1214 100x Oil Phase Plan Achro 1.25 0.1 Inf. 34  Dark Phase 1
1215 20x Achro 0.50 1.1 Inf. 34 1.0mm cover glass correction 5
1216 20x Achro 0.50 1.1 -1.5 Inf. 22 Correction Collar 5
1216A 20x  LWD Achro 0.50 1.2 - 1.7 Inf. 34 Correction Collar; for Tissue Cultures 1
1217 20x Achro 0.50 1.0 -1.5 Inf. 34 Correction Collar 5
1217A 20x Phase LWD Achro 0.50 1.2 - 1.7 Inf. 34 Correction Collar; for Tissue Cultures 1
1218 45x Achro 0.66 0.4 -0.8 Inf. 34 Correction Collar 5
1218A 45x LWD Achro 0.66 0.6 - 1.1 Inf. 34 Correction Collar; for Tissue Cultures 1
1219 45x Achro 0.66 0.4- 0.8 Inf. 34 Correction Collar 5
1219A 45x Phase LWD Achro 0.66 0.6 - 1.1 Inf. 34 Correction Collar; for Tissue Cultures 1
1223 20x Phase Achro  0.50 1.1 Inf. 34 1.0mm Cover Glass Correction 5
1224 10x Phase Achro      Inf. 34 Dark Phase 2
1225 20x Phase Achro      Inf. 34 Dark Phase 2
1227 100x Phase Achro.     Inf. 34 Dark Phase 2
1229 100x Phase Achro     Inf. 34 B-minus Phase 12
1234 10x Phase Achro      Inf. 34 Bright Phase 2
1235 20x Phase Achro      Inf. 34 Bright Phase 2
1237 100x Phase Achro      Inf. 34. Bright Phase 2
1238 45x Phase Achro.     Inf. 34 Dark Phase 2
1239 45x Phase Achro.     Inf. 34 Bright Phase 2
1303 63x Semi-Plan 0.80 0.2 Inf. 34   1
1309 40x Adv. Plan Achro 0.66 0.2 Inf. 34 Not suitable for Hemacytometer 1
1311 100x Oil Adv. Plan Achro 1.25 0.1 Inf. 34   1
1321 10x Plan Apo  0.30 1.0 Inf. 34    1
1323 40x Plan Apo  0.80 0.3 Inf. 34    1
1866 40x  . Adv. Plan Achro 0.55 3.4 Inf. 34 No Cover Glass, LWD 1
1866 LWD 40x Plan Achro     Inf. 34 Industrial, Series 3000, 2560 1
1867 100x  Dry Adv. Plan Achro 0.90 0.3 Inf. 34 No Cover Glass, LWD 1
1867 LWD 100x  Dry? Plan Achro     Inf. 34 Industrial, Series 3000, 2560 1
1867S 100x  Dry? Plan Achro     Inf. 34 Strain Free, 2560 Series, BD/DIC (not DF) 1
1891 40x Adv. Achro 0.80 or 0.85*** 0.5 Inf.  34 For Vert. Fluorescence 1, 18
1891S 40x Adv. Achro 0.80 or 0.85*** 0.5 Inf. 34 Strain Free for Pol. work 1, 18
2555 10x Plan Achro     Inf. 34 Industrial, Series 3000, 2560 1
2555S 10x Plan Achro     Inf. 34 Strain Free -- for DICV 1
2556 20x Plan Achro     Inf. 34 Industrial, Series 3000, 2560 1
2556S 20x Plan Achro     Inf. 34 Strain Free -- for DICV 1
2557 40x Plan Achro     Inf. 34 Industrial, Series 3000, 2560 1
2557S 40x Plan Achro     Inf. 34 Strain Free -- for DICV 1
2564 6.5x Plan Achro     Inf. 34 Series 2560 BF/DF  1
2564S 6.5x Plan Achro     Inf. 34 Series 2560 BF/DF/DIC (Strain Free) 1
2565 10x Plan Achro     Inf. 34 Series 2560 BF/DF  1
2565S 10x Plan Achro     Inf. 34 Series 2560 BF/DF/DIC (Strain Free) 1
2566 20x Plan Achro     Inf. 34 Series 2560 BF/DF  1
2566S 20x Plan Achro     Inf. 34 Series 2560 BF/DF/DIC (Strain Free) 1
2567 40x Plan Achro     Inf. 34 Series 2560 BF/DF  1
2567S 40x Plan Achro     Inf. 34 Series 2560 BF/DF/DIC (Strain Free) 1
2568 60x Plan Achro     Inf. 34 Series 2560 BF/DF  1
2568S 60x Plan Achro     Inf. 34 Series 2560 BF/DF/DIC (Strain Free) 1
3006 6.5x Adv. Achro  0.20 18.0 Inf. 34 Industrial, Series 3000, 2560 1
3007 45x 0.66 Inf 34 17
3022 10x Epi. Obj. 0.25 6.4 Inf. 34 No cover glass 3
3023 20x Epi. Obj. 0.50 1.3 Inf. 34 No cover glass 3
3024 40x Epi. Obj. 0.66 0.5 Inf. 34 No cover glass 3
***See note at page bottom on Phase Contrast types 
1120115W 43x Phase       160 34 Bright Contrast -- High 14
1120127W 97x Phase       160 34 Bright Contrast -- High 14
2120109W 10x Phase Achro     160 34 Bright Contrast  -- Medium 11
2120112W 20x Phase Achro     160 34 Bright Contrast  -- Medium 11
2120115W 43x Phase Achro     160 34 Bright Contrast  -- Medium 11
2210127W 97x Phase Achro     160 34 Bright Contrast  -- Medium 11
2220109W 10x Phase Achro     160 34 Dark Contrast -- Medium 11
2220112W 20x Phase Achro     160 34 Dark Contrast -- Medium 11
2220115W 43x Phase Achro     160 34 Dark Contrast -- Medium 11
2220127W 97x Phase Achro     160 34 Dark Contrast -- Medium 11
3120109W 10x Phase Achro     160 34 Bright Contrast  Low 14
3120112W 20x Phase Achro     160 34 Bright Contrast  Low 14
3120115W 43x Phase Achro     160 34 Bright Contrast  Low 14
3120127W 97x Phase Achro     160 34 Bright Contrast  Low 14
3220109W 10x Phase Achro     160 34 Dark Contrast Low 14 
3220112W 20x Phase Achro     160 34 Dark Contrast Low 14
3220115W 43x Phase Achro     160 34 Dark Contrast Low 14
3220127W 97x Phase Achro     160 34 Dark Contrast Low 14
6420115W 43x Phase Achro     160 34 B-Minus Contrast Medium 14
6420127W 97x Phase Achro      160 34 B-Minus Contrast Medium 14
8420109W 10x Phase Achro     160 34 B-Minus Contrast Low 14
8420112W 20x Phase Achro     160 23 B-Minus Contrast Low 14
8420115W 43x Phase Achro     160 34 B-Minus Contrast Low 14
8420127W 97x Phase Achro     160 34 B-Minus Contrast Low 14
876299 20x Achro 0.50   160 34    9
881424 10x Achro  0.25   160 34   9
882836 43x Achro 0.66   160 34   9
922968** 50x  Reflecting 0.56          Reflecting, used for Ultraviolet studies ca: 1956 9

*In the only case I know of, AO, strangely, reused a Catalog number.  In 1969, the Cat# 1029 was clearly a 50x (without a iris diaphragm).  Then sometime later AO brought out a Cat# 1029 100x Oil ( I've seen three examples of these -- they were 'new style' objectives so I would guess the 1029 was maybe produced in 1975 or 1976?)

**Unsure if this whole number is the Cat#.  Only have seen on example of this objective, but this is what was on it:

Stan Ayers -- "I just bought a phase-contrast microscope. It seems to be from the '50's. The objectives and condenser turret are familiar, except for one. There's a 50x reflecting objective, marked 922968. I have never seen one of these, and was wondering what they are for, or why they were specified."

Needham's 'Practical Use of the Microscope' p.137: "A recent computation is that of the American Optical Company.  The reflecting objective is 50x with an N.A. of 0.56.  The quartz optics made by this Company for the objective are a 10x Huygens eyepiece and an Abbe substage condenser."  Read the full account here.

***The catalog says N.A. 0.80, but I've seen, on ebay, an example that clearly says 0.8

FAQ Question:  Can I use other manufacturer's 160mm T.L. objectives with my 160mm T.L. AO Objectives?

Answer:  Sure . . . for almost 100 years, people have been happily exchanging 160mm objectives  But, there could be a few 'gotchas'.  First, color and flatness correction sometimes occur in an intermediate lens (e.g. some B&L designs) or, more commonly, in the eyepiece.  But you have a good chance of being successful without any loss of resolution and contrast.

Also, remember the parfocal distance challenge.  Sometimes, if the difference isn't too great, you can use shims between objective and nosepiece to defeat this challenge (e.g. see www.cynmar.com's affordable parfocal rings).  

A very useful table of parfocal distances is found in Mikrofibel page 55 -- 1st column = Manufacturer, 2nd column = tubelength, and the 3rd column = parfocal distance in mm -- which is what you need to know.  Can't read German?  Me neither, but 'mining' this document we can produce a table of good candidates as below:

Manufacturer Parfocal Distance (mm)
AO Spencer 34*
LOMO (Note: the U.S. distributor is OpticsPlanet) 33   
B&L (Bausch & Lomb) 35.67**
Olympus (the earlier - 1950's & 60's - short barrel) 36
Meopta 36
WILD 37
Reichert 37
WILL (from Wetzlar, not from Hund  37

FAQ Question:  Can I use other manufacturer's infinity corrected objectives with my infinity corrected AO Objectives?

Answer:  Not like you can 160mm objectives -- in theory, many advise against it.  But when did that ever stop you? :-)  After a rousing discussion on Yahoo's Microscope group about this (see this message for instance), and reading various references, I have concluded (with not much authority I might add :-)  ) that it may work, or it may not work, depending on which objectives and which scopes you use them on.  A very good reference, and read, is: 

http://www.microscopyu.com/articles/optics/cfintro.html

that addresses the history and issues well.  

Basically, bottom line, even an infinity system is designed with a tube-length in mind for the upper part of its optical train, which varies by manufacturer, and the design 'mismatch' can cause trouble when mixing various makes of infinity corrected objectives.  (Note:  A interesting overview of objective correction can be found here.  The issue comes down to the question: "How can a single objective cost $4000?",  with the answer:  "Because there's a lot to correct for in attaining the ultimate resolution.")

But theory is one thing, practice is another.  In practice, people have found that it is often possible to swap infinity corrected objectives without appreciable, or at least, noticeable, loss of resolution and contrast.   Remember though you will still face the parfocal distance challenge mentioned above.

FAQ Question:  Can I use Leitz 170mm T.L. lenses on my 160mm T.L. AO Scope? 

Answer:  Sure.  The Parfocal distance problem will be there (i.e. many Leitz lenses are 45mm parfocal, some are 37mm parfocal, etc.****), but it will work.  The definitive document on this is Leitz-160mm-Memo.pdf  at Gordon's site -- a very interesting read.


* Note: Determining the parfocal distance of an AO objective is not as easy as it sounds -- well accurately at least.  I have two LOMO 160mm T.L. objectives which are very clearly stated by the manufacturer to be 33mm parfocal.  Using the 1 micron graduated fine focus on the Series 4 scope, I found these LOMO objectives to be within 0.065mm parfocal to each other.  I then used them to compare against same power AO 160mm T.L objectives (which are within 0.040 mm parfocal to each other) and found the AO's parfocal distance to be almost exactly 1.0mm longer than the two LOMOs (0.925 mm in one case,  1.030 mm in the other).  So using the two Russian objectives as a standard (well, it was the best I had), I compute the AO Objective's parfocal distance to be 34mm.

**Note:  I compared an AO 97x Oil objective to a B&L 97x Oil objective -- both gave excellent images (by the way, the 97x AO was exactly parfocal with the 10x AO objective noted in the LOMO comparison above).  The B&L parfocal distance was exactly 1.67mm longer than the AO's distance.  Thus 34 + 1.67 = a 35.67mm parfocal distance for B&L objectives.  One message on the Yahoo's Microscope forum says that B&L objectives are 35.5mm parfocal, but that is 0.17mm too short per my measurements.

***Note:  Quoting from Needham (1958 -- The Practical Use of the Microscope, p. 153):  "American Optical Company (Spencer) has designed objectives in which the central beam is not changed while the diffracted light is both retarded and reduced in intensity.  This modification has been named by them, B minus contrast.  American Optical manufactures a very complete series of phase-contrast objectives for bright, dark, and B minus contrast, each with three degrees of contrast of low, medium, and high . . . The consensus of opinion of several of the foremost independent workers with the phase-contrast microscope is that the Zernike, 1/4 (lambda) retardation, negative (bright) contrast or positive (dark) contrast is preferred for the great majority of objects with very little contrast.  Also they object to the fact that too many variations in phase-contrast objectives complicate and confuse the beginner in this field, and that such modifications are not generally necessary, and that they add greatly to the cost."

****Note:  Leitz objectives are a tough one to unravel.  Older Leitz objectives (before 1960?) seem to be all 37mm parfocal.  But when Leitz brought out PL (plan) and NPL (neo plan) objectives, they designed them  with the longer 45mm parfocal design.  But, unfortunately, it turns out to be no that simple.  Note Mike Andre's comment to a question about availability of 170mm T.L 37mm Phaco or PV objectives -- Yahoo Microcope forum message #33059:

"Re: Looking for a Leitz Phaco or PV objectives -- 170mm T.L. , non-plan

Hello all,

Looking at my copy of the Leitz manual "Image-forming and Illuminating Systems of the Microscope"***** it states on page 49: Phaco phase contrast objective for the Zernike condenser are 170/0.17/45mm (with the exception of the Fl Oel 70 - 170/0.17/37mm)

Page 50 lists the Phaco NPL Phase Contrast Planachromats for the Zernike condenser at 170/0.17/45mm, but page 51 lists PV Phase contrast objectives for the Heine condenser at 170/0.17/37mm (with three exceptions for 170/0.17/38.5mm!)

I have sets of the achromat phacos as well as the NPL Phacos, all or which are 45mm (none for sale, I'm afraid!)

Hope this helps.

All the best, Mike"

***** Don Grybeck kindly has contributed this wonderful document, which was subsequently scanned, and you can download it here:  "Image-forming and Illuminating of the Microscope -- objectives, eyepieces, and condensers" (23.4 MB zipped file)   


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