Search found 6272 matches

by apochronaut
Thu Mar 28, 2024 1:17 pm
Forum: Microscopes and optics
Topic: Field number vs. field stop diameter in "negative" eyepieces
Replies: 2
Views: 67

Re: Field number vs. field stop diameter in "negative" eyepieces

So then, why not use angle as an indicator of f.o.v. ? Would it not be a better indicator of the field width?
by apochronaut
Thu Mar 28, 2024 11:49 am
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34599

Re: Leica Reichert Jung Polyvar (models)

No , we aren't talking apples and apples. ... I will rephrase that because either I jumbled the words or you misunderstood them. A 15X/20 eyepiece produces an image circle that is the same size that a 10X/30 eyepiece would produce. I don't think it can ever be apples to apples unless you specify mo...
by apochronaut
Thu Mar 28, 2024 11:19 am
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34599

Re: Leica Reichert Jung Polyvar (models)

It is apochronaut, not apochromat. That is a type of lens. It is not always easy to rely on one's perception of things around you when you are bound in a system and can't get out. I used the term image circle to describe what is being seen because you were relying entirely on theory out of a book, w...
by apochronaut
Thu Mar 28, 2024 10:06 am
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 42
Views: 1288

Re: Do I need another objective?

All you need is an iris equipped objective, a .90 corrected condenser and a corrected condenser that allows the objective to work at or above the calculated combined N.A. to determine that.....and probably a good diatom slide, maybe something like p.angulatum.
by apochronaut
Wed Mar 27, 2024 10:03 am
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34599

Re: Leica Reichert Jung Polyvar (models)

Your example of a 15x/20 eyepiece returning a30mm isn’t possible. No , we aren't talking apples and apples. You seem entiely stuck on the actuality of the true measurements you have provided and that is all true mathematically but you had to get out a calculator to determine at least some of them d...
by apochronaut
Wed Mar 27, 2024 8:13 am
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34599

Re: Leica Reichert Jung Polyvar (models)

Only if the camera was in my eye. The image circle at the enrance to the eye is 20mm. If you hold a quarter out at arms length it will obscure the moon but if you bring it right close to your eye it will obscure a third of the sky.
by apochronaut
Wed Mar 27, 2024 12:55 am
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34599

Re: Leica Reichert Jung Polyvar (models)

Of course. You are viewing the exit pupil from what, 10 inches away with a camera lens. I don't know where uou have your screen. My point was that the apparent field your eye sees right st the cornea is 20mm. Put the scale at your eye.
by apochronaut
Tue Mar 26, 2024 12:41 pm
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 42
Views: 1288

Re: Do I need another objective?

Look up the Rayleigh Criterion for microscopes.
by apochronaut
Tue Mar 26, 2024 9:55 am
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34599

Re: Leica Reichert Jung Polyvar (models)

F.N. is an arbitrary system. It is a code system stamped on some eyepieces, only some. There seems to be a begrudging compliance on the part of manufactuers. Maybe there is a reason? In existence, and you can look them up on ebay right now and find at least some of these, so they sre pretty common a...
by apochronaut
Tue Mar 26, 2024 3:15 am
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34599

Re: Leica Reichert Jung Polyvar (models)

The hangup is the difference between f.o.v. and image circle. All of the stuff you posted is obvious but the system as it exists does not adequately or easily explain or predict to a naive user that a 15X eyepiece with a smaller F.N. will have a larger viewing field ( not field of view) than a 10X e...
by apochronaut
Tue Mar 26, 2024 1:26 am
Forum: Microscopes and optics
Topic: Substituting LED bulb for incandescent bulb
Replies: 7
Views: 330

Re: Substituting LED bulb for incandescent bulb

Your microscope is an educational microscope that was originally intended to be used with a med. blue filter. The filter increases the resolution and makes the image more like daylight: more pleasing to the eye. In that illuminator the filter is incorporated into the lensing system above the illumin...
by apochronaut
Mon Mar 25, 2024 9:27 pm
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 42
Views: 1288

Re: Do I need another objective?

There was a bit of a condenser revolution, possibly after your Universal was minted? Either there was a paper presented at a conference or something akin about how a high percentage of users don't oil their condensers or wider field planarity became mainstream. Probably some of both. After a certain...
by apochronaut
Mon Mar 25, 2024 10:57 am
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34599

Re: Leica Reichert Jung Polyvar (models)

How do you know it is clear to everyone? What is clear is that some people think that an F.N. of 16 has a smaller field than an F.N.of 20 because that is what is prnted on the eyepiece , not that the product of magnification and field gives the field size. How many times does the question of why is ...
by apochronaut
Mon Mar 25, 2024 2:00 am
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 42
Views: 1288

Re: Do I need another objective?

It is essentially a funnel stop but there is no funnel because the back lens is pretty flush with the top of the objective barrel, so it is flat. I found a rear diaphragm from a euchered objective that had a hole just a little smaller and sticking it on the existing diaphragm worked. Temporary and n...
by apochronaut
Mon Mar 25, 2024 12:04 am
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 42
Views: 1288

Re: Do I need another objective?

Perhaps apochronaut can chime in with some comments on the immersion objectives available from BestScope? Harry My involvement with Bestscope is limited. I had some involvement with them in 2017 and 18, almost purchasing a BS-2081, which is a Chjnese version of the E 200 but can be tricked out more...
by apochronaut
Sun Mar 24, 2024 8:53 pm
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34599

Re: Leica Reichert Jung Polyvar (models)

It's only intuitive if you already know it. I don't personally have a problem with it but for those unfamiliar with the system it id difficult. The way it is done in astronomy makes much more sense and the microscope world could learn a bit .
by apochronaut
Sun Mar 24, 2024 5:57 pm
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 42
Views: 1288

Re: Do I need another objective?

I could have sold you one cheaper and had it there in 10 days, Pete.
by apochronaut
Sun Mar 24, 2024 11:56 am
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34599

Re: Leica Reichert Jung Polyvar (models)

Yes but the f.N. only matches the real or viewed ield with a 10X eyepiece.because they are the default and the system's logic is based entirely on 10X eyepieces. Other eyepiece magnifications can still have any F.N. as viewed through the theoretical 1X objective but their F.N. no longer equals the s...
by apochronaut
Sun Mar 24, 2024 1:29 am
Forum: Pictures and Videos
Topic: 4 different 40X Reichert phase infinity objectives used in an AO 10 stand.
Replies: 3
Views: 237

Re: 4 different 40X Reichert phase infinity objectives used in an AO 10 stand.

# 3 is a bit of a unique objective. It has a very thin and wide annulus, not at all like the annulus in it's two companion objectives and it is situated deeper in the lens stack. It will not work with the 40X condenser annular diaphragm. I have to use the 100X and manipulate both the annular diaphra...
by apochronaut
Sun Mar 24, 2024 1:14 am
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34599

Re: Leica Reichert Jung Polyvar (models)

I refrained ftom using telescope terminology. The term apparent seems to be a no no when it comes to microscopes but is widely used when it comes to telescopes. I have used it in the past. In terms of angular field of view then, a 15X eyepiece with an F.N. greater than 13.33333... will have an angul...
by apochronaut
Sat Mar 23, 2024 9:05 pm
Forum: Microscopes and optics
Topic: Leica Reichert Jung Polyvar (models)
Replies: 88
Views: 34599

Re: Leica Reichert Jung Polyvar (models)

The pictures I posted are showing between 18.3 and 20.25 units, with 20 units across an eyepiece that is listed as having an F.N. of 20mm, so the scale must be in mm. So, I am showing the F.N.'s of the eyepieces but it doesn't matter to the current discussion about 15X eyepiece fields because there ...
by apochronaut
Sat Mar 23, 2024 7:43 pm
Forum: Pictures and Videos
Topic: 4 different 40X Reichert phase infinity objectives used in an AO 10 stand.
Replies: 3
Views: 237

Re: 4 different 40X Reichert phase infinity objectives used in an AO 10 stand.

I decided to check the specs. on the slide. The total thickness is 2.12 mm with a .21 coverslip, so it definitely stresses the condensers capability to project the diaphragm accurately, not to mention the overripe sample thickness. The point of this excercise was to illustrate that the 45mm Reichert...
by apochronaut
Sat Mar 23, 2024 7:31 pm
Forum: Pictures and Videos
Topic: 4 different 40X Reichert phase infinity objectives used in an AO 10 stand.
Replies: 3
Views: 237

4 different 40X Reichert phase infinity objectives used in an AO 10 stand.

This is a thread branched off of another recent AO/Reichert/Leica thread. https://www.microbehunter.com/microscopy-forum/viewtopic.php?f=5&t=8625&p=143035#p143035 Four images of the same Fragillaria diatom taken through 4-40X phase contrast infinity objectives with the 182.5mm reference length that ...
by apochronaut
Sat Mar 23, 2024 2:17 pm
Forum: Microscopes and optics
Topic: Oxidation on front assembly / retraction stopper
Replies: 7
Views: 376

Re: Oxidation on front assembly / retraction stopper

Anhydrous Ethyl Alcohol. U.S.P. + 432526. and yes, the coatings may have been imperfectly deposited but who would suspect that at the outset. Previously I.P.A. was probably the strongest solvent I had used on them with no effect. Ethanol speckled them immediately. Henceforward I use nothing stronger...
by apochronaut
Sat Mar 23, 2024 12:02 pm
Forum: Microscopes and optics
Topic: Oxidation on front assembly / retraction stopper
Replies: 7
Views: 376

Re: Oxidation on front assembly / retraction stopper

I once had ethanol damage a costing that was on an objective made in Germany.
by apochronaut
Sat Mar 23, 2024 8:05 am
Forum: Microscopes and optics
Topic: Oxidation on front assembly / retraction stopper
Replies: 7
Views: 376

Re: Oxidation on front assembly / retraction stopper

The alloys in those front bezels are usually unknown but are designed to be corrosion resistant. They have been variously alloys with anything from iridium through gold to nickel. The nickel alloys obviously weren't great but they were never intended to get wet with anything but did. One front bezel...
by apochronaut
Sat Mar 23, 2024 1:19 am
Forum: Microscopes and optics
Topic: Do I need another objective?
Replies: 42
Views: 1288

Re: Do I need another objective?

An option is always a pair of 12.5X or 15X eyepieces. Both , if designed as proper extensions of the system you have, will provide quality imaging and a larger image circle at any given magnification than a 10X eyepiece will provide, as long as the N.A. of the objective is high enough. Drop the deci...
by apochronaut
Fri Mar 22, 2024 6:39 pm
Forum: Microscopes and optics
Topic: who has picture of this Reichert objective?
Replies: 3
Views: 268

Re: who has picture of this Reichert objective?

Reichert changed the lettering format a few times. There is this one you may have already seen. Not exact and not great pictures. https://www.ebay.at/itm/363916493207?itmmeta=01HSKQ1RCV42YQWV0A6CK0WYA3&hash=item54bb1d0197:g:3MsAAOSw~m1i2SkR&itmprp=enc%3AAQAJAAAA4HLOI1NbIitnVtYcXgilgOq0CNur%2FSWhVynr...
by apochronaut
Fri Mar 22, 2024 6:31 pm
Forum: Microscopes and optics
Topic: Polylite SC endusers(?)
Replies: 49
Views: 2090

Re: Polylite SC endusers(?)

It looks like it might be decentered to the right some plus some pincushion curvature. The brown line that runs top to bottom on the left side is slightly bowed in and there is some ca bordering the characters to it's left.
by apochronaut
Fri Mar 22, 2024 2:15 am
Forum: Microscopes and optics
Topic: Polylite SC endusers(?)
Replies: 49
Views: 2090

Re: Polylite SC endusers(?)

So the telan lens is not contributing any corrections for ca or likely sa either. It is just a convergence lens. The eyepieces that I have from some Poly microscope, I just today pictured in your other thread , seem to have some correction for curvature of field. They have a fairly pronounced concav...