MicrobeHunter.com Microscopy Forum

A bit hard to follow the wiring still but yeah, probably a TRIAC dimmer on the primary side. In any case, I agree with this: According to the picture the cables seem to come directly from the transformer as far as I can see. The current is not rectified, is AC and so the polarity does not matter. No...

How does the e400 behave without the lens? I just tried removing the lens from a Reichert Microstar IV. (AO/Reichert call it the collimator in patents, rather than field lens.) The field iris can still be focused by lowering the condenser until there is ~1.4 mm gap between the top lens and slide whi...

Going back briefly to your earlier post: ...diffuser that, I would guess, acts as the light source for Kohler illumination purposes. There are a lot of discussions around whether a particular location (filament, diffuser, field iris, etc.) can be thought of as "the" illumination source. For systems ...

If I understand correctly from the video the field iris is in the base before the mirror in the light path? If so what matters is the distance lens to iris relative to the focal length of the lens. Since it is a relatively modern microscope I would guess the iris is placed one focal length away so t...

A good example of what apochronaut is talking about that I came across recently: OSRAM 64625 HLX vs. 64623 HLX . Both are 12V/100W GY6.35 base with the same filament position (30 mm LCL) but the 64625 has a more compact filament operating at higher temperature (4.2x2.3 mm at 3450 K vs. 4.7x2.7 at 33...

There seems to be a round-shape component on the bottom of the case with some capacitors. Could be a rectifier, but can't be sure. The cables go to the front panel. What might it be? TRIAC dimming circuit on the primary side? I can't see the primary wires from the transformer in the photo, too low ...

Cool photo, I didn't realize epi DIC could work so well on stuff like this. After all the discussion in Louise's thread these reflections in the larger features look familiar...

Yeah but there's no detailed info about how he set up the prisms etc. Like how he got the fringes to align etc. I interpreted this as saying that the strong blue and magenta background was interference colors from the beams/polarizers, which would indicate that setup differs from normal DIC: Just o...

Saul's images look interesting but they are taken with a 20x objective so it's not clear exactly how he set things up... I think this post is saying that the upper beam (in the slider to the left of the condenser in the first photo) goes into a slot just above the objectives where a similar 3D-prin...

I don't any reason to doubt the final results in Rathi, most likely just a change in the 3/32" material McMaster sells (as mentioned earlier the 7/32" I have appears roughly consistent with fig. 3(b)) and maybe some of the implementation details are incorrect due to hurried (summer project) paper-wr...

The insert at 100% shows a line separated from the edge of the black division marker by about 50 pixels, or 0.0005mm. I take it this line is an effect of diffraction and represents the point beyond which no further detail can be resolved, even if all else were perfect? Seems more common to measure ...

or you can go old fashioned and resolve the stria of a Amphipleura pellucida diatom Yeah I like how even in recent, highly-technical papers on optics/microscopy there are sometimes still shots of diatoms. The ultimate test to earn credibility among microscopists, no integral transforms necessary...

Got 3/32 bar from McMaster per Rathi, unsurprisingly shows similar strong inherent birefringence as the 1/16 and 1/8 I already had, didn't bother taking a photo. So why does Rathi fig. 3(b) shows so little shift of the fringe pattern? McMaster changed suppliers, or supplier changed manufacturing met...

That doesn’t fit my definition of resolution Figure 6(d) here does : http://zeiss-campus.magnet.fsu.edu/articles/basics/imageformation.html Two pages discussing the relationship among PSF (as in Zeiss fig. 6(d)). LSF, and edge response with some nice illustrations: https://www.strollswithmydog.com/...

MichaelG. wrote: ↑

Tue Jul 20, 2021 9:33 am

I see nothing in the posted photo to demonstrate resolution of two points separated by half a micron.

What's wrong with the plot crb5 posted showing ~500 nm transitions at the edges of the lines on the calibration slide?

So if I can use a scale of known dimensions to define the length of a division in the EP graticule, then I think that's probably the information I want. Unless I screwed up somewhere. No screw-up, ~500 nm from your first, second, and third posts in the thread is correct. ...that is the wavelength o...

... I suggested using pixel pitch as a measuring scale, because all the other factors are 'nominal' values. Maybe I misunderstand what you are suggesting, but Markus is measuring directly in relation to the calibration slide so no "nominal" values other than the specification of the slide itself ar...

Is it not correct to look at one division on the slide, which we know is 0.01mm, and divide by the number of EP divisions that fit within? In this case, 0.01mm /19 = 0.0005263158. I don't see any problem with this, the projected size of the graduations in the object plane depends only on the magnif...

Scarodactyl wrote: ↑

Sun Jul 18, 2021 5:03 am

Scrolling through pages of bulbs is what this hobby is all about.

Probably a ways to go before I can be considered a master of the bulb-page-scrolling hobby, but it's a start:

For orientation, here below the simplified "polarnet" from Bennet's book... Glad you pointed this out, I never noticed polanret was described in that book and didn't think to look when it came up earlier in the thread. Oh yeah, also I didn't use an analyzer. That might be a useful addition. Abbrevi...

Interesting test Bram, definitely looks like there is something going on. To make sure I understand the arrangement... is this film sold specifically as 1/4 wave, or just some random film that happens to be close? So then you have a slit below the condenser to match the strip, and in the phase teles...

What do Nikon non-CF DIN objectives look like? I thought you were talking about CF because you referenced Seta's CFN objective you repaired. I have two older non-CF Nikon objectives that came mismatched with some B&L stuff I bought, haven't tried them on anything yet, but these are JIS with shorter ...

Interesting, do the Nikon heads for these objectives use prisms or mirrors? One note is that in the Microstar/Diastar the Reichert Austria objectives have a very slight lateral ca. It is almost imperceptible but cameras pick it up worse. This is cured by swapping to #145 eyepieces, which are slightl...

I wonder if they were able to measure the output power of the one that caused the damage? I have read that laser pointers can be more powerful than advertised, either poorly controlled manufacturing or intentionally mislabeled to avoid regulation.

Thanks Michael, it is sturdily built but not too heavy, should be nice for the kids to use. Quite a bargain as long as we don't include any hourly rate for all the time I spent scrolling through pages of light bulbs...

I haven't tried to make any sort of fixture yet, still holding the beam between my left and right hands with locking pliers and bending manually as in the previous photo with the larger 1/4" x 1" x 8" bar. The shiny things in the upper left and lower right corners are the jaws grabbing the ends of t...

Ended up replacing the line cord with a powerpole connector and getting 12 V "1076" type bulbs which have the same base. Specifications vary slightly among manufacturers but roughly: 12.8 V, 23 W, 2800 K, 400 lumen, 200 hour life. Overdriving to 14 V (28 W) gives fairly white (for a tungsten bulb) l...

Not ideal, but maybe useful as a workaround if low-birefringence material is hard to find -- stacking two beams with optic axes of the inherent birefringence 90 degrees apart should cause inherent (but not stress-induced) birefringence to cancel. Seems to work reasonably well in a crude test, first ...

One thing that I started thinking about is if the Sanderson prisms are stable over time, or if the shearing characteristics will change over time due to fatigue. Have you read anything about this? Just noticed this is mentioned briefly in section 2 of: Biss et al. - Differential schlieren-interfero...

Regarding whether the fringe pattern is shifted toward the compressive or tensile side of the beam... should depend on whether the optic axis of the inherent birefringence is perpendicular or parallel to the beam axis, I think. You are cutting beams from sheets like Schulz and also saw both cases, r...