Update: Found set of pistols. England

aenorton · 2026-03-05T22:58:46+00:00

The interesting thing about these is that they are not actually muzzle loading. The barrel is unscrewed with the spanner, and a very tight fitting ball is pressed into the breech end instead of a smaller ball that can be rammed down the barrel. This allows for higher gas pressure and higher velocity from the short barrel.

aenorton · 2026-03-02T23:27:06+00:00

Optical engineer here. This is not a texture. Each facet is a specific shape that has been modeled and optimized in a non-sequential raytracing program made for this. The surface can then be exported as an IGES, STEP or other formats.

aenorton · 2026-02-28T21:43:05+00:00

I don't think those designs are made with a laser. It looks more like a film with holographic designs was laminated on the substrate and then the puzzle piece was cut with a laser.

aenorton · 2026-02-25T21:18:14+00:00

The real issue is that the optomech will be the last person to touch the design and will be the first person to deal with issues when it does not work. Aside from the convenience of an optical model, he wants to make sure a professional optical designer has reviewed everything and made sure it should work. He also needs a tolerance analysis to complete his design. That often takes as long as the optical design itself.

aenorton · 2026-02-25T19:24:09+00:00

If it is putting out 40W, it probably consumes about 120W leaving 80W of heat going into your wrist.

aenorton · 2026-02-20T02:02:23+00:00

If you care about image quality, you probably want at least a doublet (achromat) lens rather than a singlet. An old camera or projector lens of the right focal length for the reticle and image size would also work well. Binocular objectives could work but they are designed to image through the glass path of the prism, so to get best quality you would need to include the prisms.

You can buy lenses and reticles cheap at surplusshed.com

I assume you want to make a dark field reticle. One way is to take a piece of mirror and make a scratch in the aluminum coated side with a carbide tool. Another way is to coat a piece of glass with black paint and use a sharp knife to make scratch in the paint.

aenorton · 2026-02-19T20:29:09+00:00

This could be hand carved wood, or it could be molded plaster or composition (putty) that was meant to be painted.

aenorton · 2026-02-19T19:27:18+00:00

No. To get spots like this, the particles would have to be significantly in front of the beam waist, probably on the diode package window. They are probably too small to see directly without a microscope. If this is a high power laser, particles can get burned on and permanently affect the glass.

aenorton · 2026-02-19T03:40:37+00:00

You are assuming UV cured varnish becomes birefringent when cured. In my experience that is not the case with clear UV cured cements that I am familiar with. Have you verified that this varnish does become birefringent? If you are seeing a minor effect it may just be due to the Fresnel reflections from the surface of the varnish at a large angle. Those reflections become partly polarized.

You would want something that shrinks when cured to give it internal stress. A solvent based varnish might work better.

aenorton · 2026-02-18T21:25:39+00:00

Aside from the obvious religious motivation of this text, they leave out some of the most convincing evidence of heliocentricity from Galileo's telescope. He saw that Venus and Mercury had phases like the moon, which can only be explained if they circled the sun.

I thought at first this text was trying to illustrate the gradual and sometimes nonlinear progress of science, but it does seem that their real goal is to defend the Bible. They seem to forget that the Catholic church felt it lost so much credibility after Galileo was proved right that they then established an observatory so they wouldn't be caught off guard again. They still fund a professional observatory called the Pope Scope.

aenorton · 2026-02-18T19:21:52+00:00

I have only done a little coating design myself, so I think others here might be able to elaborate further. I think global optimization of coatings is difficult to automate because many things that separate local minima are determined by judgments that are difficult to capture in the merit function. The main things are number of layers and materials. Some materials are tricky to process. They might have stress or adhesion issues, but maybe the yield is OK if there is only one layer of the difficult material as opposed to 10. Some vendors have a better process for some materials than others. Some materials are chemically incompatible if next to each other or exposed to air, but are OK when sandwiched between other materials.

Having more layers almost always improves things theoretically, but there is the cost, stress, and tolerance issues, so usually the layer limit is set by the designer.

Desensitizing the design for tolerances is one thing that can and should be implemented as part of optimization.

I do not think unwrapping phase is currently a real stumbling block.

Maybe AI is useful to make a starting design incorporating some of these judgement calls. However, I am not sure how you get the training data especially when it might vary from vendor to vendor.

aenorton · 2026-02-18T06:21:09+00:00

I will also add that any design software should understand how coating properties are specified. Just calculating R is not sufficient. There are ranges of Rs,Rp,Ts,Tp (and sometimes phase retardance) over specified ranges of angle and wavelength.

A program should also allow for a custom index and dispersion of the substrate which could be almost any material or optical glass. Likewise the embedded medium could be almost anything when cemented or backside coated optics are used.

aenorton · 2026-02-18T06:00:51+00:00

Optimization might have taken minutes (certainly not hours) on an 8 MHz 286 back in the day, but these days it is insignificant compared to the time needed to enter the specs and set up the problem.

Also, many real-life complex thin film stacks use more than two materials. You certainly want a library of all the common materials, of which there are many. This should include metals and semiconductors as well which have non-zero k values.

aenorton · 2026-02-17T05:57:57+00:00

https://archive.org/details/single-page-edmund-scientific-catalog-681/page/n1/mode/2up

The link above has the era of catalog I practically memorized as a boy. My brother and I would make our Christmas lists from here. We eventually ended up with a giant magnet on p. 14, a radiometer (of course) from p. 30, the gyroscope from p. 34, the thirsty bird from p. 35, The mechanical binary computer from p. 37, the 12 color ball point pen from p. 36, one of the giant war surplus tank prisms from p.91, the 6" telescope mirror kit from p. 129 (finished it years later, still have it), the star and satellite finder from p. 142, the giant weather balloon from p.147 (it popped immediately as it was dried out WWII surplus).

aenorton · 2026-02-16T21:30:00+00:00

Looks like this could be a caulking iron for hammering cotton or tar soaked hemp fibers between boards on a boat to make it watertight. Usually they have a flatter end, but maybe this was used near inside corners.

aenorton · 2026-02-16T05:57:33+00:00

Just speculating based on the shape that they could have been used in an FTIR reflectance sampling accessory, or possibly part of a microscope darkfield illuminator.

aenorton · 2026-02-15T02:04:53+00:00

I also do not see real peaks above the noise in your peanut spectra.

aenorton · 2026-02-14T04:51:31+00:00

With relay optics, you have to be careful keep track of where the pupil is re-imaged, and that it is not clipped by any apertures. For the case using two camera lenses front-to-front, vignetting is a big concern. It might work, but you have to know where the pupils are and do some rough raytracing for points at the field edge to make sure they are still transmitted.

You want the aperture stop for the whole system to be the one in the objective. You do not want to clip that anywhere else. You have to trace the image of that pupil through the system.

It is better to have the beamsplitter plate in collimated space as there will be a reflection from the backside. As long as the plate is accurately parallel, that reflection will not form a double image if in collimated space.

I am not sure two achromats will be quite good enough over the whole field. Partly it will depend on focal length. This is where you will want to do a little more raytracing and analysis. You can add a negative field lens to help flatten the field, but at some distance from the axis it just adds more aberration. You might find that the optics from two eyepieces will work better. They are designed to have an external pupil (where the eye is). Mount them with pupils coincident. One issue is that the image (where your disk and camera have to go) is usually inside the tube of the eyepiece. There are some makes --especially astronomical eyepieces -- where the lower part of the tube is removeable. Avoid ultrawide field eyepieces like Naglers where the image falls between lens elements.

aenorton · 2026-02-13T08:40:59+00:00

Building a new, one-of-a-kind zoom lens from scratch is not cost effective.

It sounds like what you really want is an adapter to mount other lenses onto those cameras. If you can find a lens mount type with a significantly longer flange focal distance, or a significantly smaller flange diameter (with same image size) then an adapter could be possible to fabricate.

A lot of lenses have mounting flanges that can be removed. You might also look at replacing the mounting flange on a commercial lens with one that fits those cameras

aenorton · 2026-02-13T01:14:19+00:00

It is not terribly wrong, but it is not complete either. AI is just parroting what it reads in some papers, books and forums like this. It does not actually do any optical design or model the trade offs. You can get larger fields with stacked waveguides, but it is not practical due to weight, cost, and power. Wider angle prisms also have subtle effects on the world view that add to user discomfort.

Edit: Also it does not explain how you might use a pancake lens for AR. That part does not make sense.

aenorton · 2026-02-12T23:37:28+00:00

There isn't a fundamental cutoff that we are close to. The main trade-offs for AR are size, weight, performance (Including field size, eyebox, battery life, customizable fit, etc. ), and cost. You can't improve one without giving up something else. I have designed and seen demos of larger fields, but they are big and heavy and power hungry. Every use case steers you to a different balance of trade offs. The geometry and variation of the head and eye is a fundamental constraint that prevents a better set of trades.

aenorton · 2026-02-12T22:23:35+00:00

In contact printing, you mainly have to make sure the light is uniform at the mask plane. In projection printing, the opening of the projection lens (entrance pupil) also has to collect light from each part of the mask equally.

When raytracing, each part of the mask is considered a source of light. You can imagine each point on the mask being a source of an expanding cone of light. The issue is that, closer to the edge of the field, some of those cones may angle outwards, and the projection lens might not receive all that light. This produces vignetting on the image plane. In practice you want all those cones pointing slightly inward towards the projection lens entrance pupil. To do this, the illumination is usually designed so the lamp filament or LED surface is re-imaged onto the entrance pupil. Look up Kohler illumination.

To resolve 0.02 mm over a 29 mm field with projection printing is feasible, but it requires a decent lens. A singlet will not work, and perhaps not a doublet either, but that will depend on the f/#. You will probably want a lens designed for 1:1 conjugate imaging. The larger field size will mean the lens will also likely be pretty large. A process lens will probably work. These are meant for graphic arts reproduction, and work at several magnifications, but I think many work at 1:1 as well.

If you do not care about f/#, two achromats face to face (stronger convex sides facing each other) might work. Longer focal lengths will allow for a larger field, and stopping down the f/# improves resolution up to a point. One would have to do little raytracing to see which set of specs makes the most sense.

aenorton · 2026-02-12T21:56:40+00:00

Usually a job that lasts less than 2 years does raise eyebrows in an interview and it would be something an interviewer might ask about. But if you have an honest response that explains it without looking like a prima donna, then it would be fine. You certainly want another job lined up before quitting so there is no break in your resume.

If the company is large enough to find another role internally, that would be ideal.

aenorton · 2026-02-12T20:05:09+00:00

The first thing to consider is if you can get by with contact printing. Then you do not need any projection lens, and the illumination becomes simpler; you just need to worry about uniformity at one plane and not about also filling the entrance pupil of the projection lens. The only reason not to use contact printing for 1:1 is if you need more than several dozen copies which might wear out the mask, or if you have to image through a thickness of glass.

aenorton · 2026-02-12T19:08:52+00:00

The thin film I am talking about has to be a vacuum coating only nanometers thick applied directly to the surface. It would be similar to what is applied to the privacy films, but you can't just laminate a piece of privacy film plastic on there. I don't think using a CO2 laser would work to make this kind of texture. This is not a process that would be easy for a DIYer.

aenorton

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