Recent content by Andy Resnick

Really excellent photos- both compositionally and technically (exposure, etc)- thanks for posting!

Another altered carbonatite: Altered carbonatite. A veinlet of carbonatite intrudes into an existing carbonatite pluton, bisecting a crystal of phlogopite. Based on Notebook LM output, appearance seems to be a result C4 contact metasomatism. Here’s a (IMO) a pretty good analogy...

Yes, but the amount of energy radiated by the wire will be much lower than the sun. The amount of energy you need to absorb to protect you from the amount of UV radiation emitted from a tungsten oxide wire is considerably less than required to block UV from the sun.

Interesting question- one I had not thought of. First, confined plasmas have a variety of radiation emission mechanisms, not just blackbody but also synchrotron and "bremsstrahlung". There are also emitted neutrons in addition to photons. I did find a brief summary of the safety measures in...

Carbonatite, Fen Complex. This sample has a significant amount of apatite, generally arranged either in aggregations of elongated anhedral grains or larger isolated subhedral crystals. Minor amount of altered phlogopite, which generally occurs as medium-to-large, isolated crystals...

Well.... if you know the emissivity, then I would agree that a commercial IR detector/camera can hit that 5% accuracy. The problem is if you don't know the emissivity.....

But that's sort of my point- without any 'ground truth' data, it's not possible to accurately determine the temperature of an unknown material just by remotely detecting the IR radiation emitted from it. And I would go further and say +-5% is wildly optimistic. Well.... that depends entirely on...

I'm not entirely sure what you mean- for example, MWIR (3-5 micron band) is well suited for imaging 'hot' internal combustion engines while LWIR (8-12 micron band) is good for living objects and room temperatures. In both of those wavebands, an object's emissivity is most definitely not...

I think the problem is more difficult than that- the emissivity can vary wildly over the relevant waveband (especially either MWIR or LWIR bands) and so, regardless of the spectral sampling you want to do, you end up having to assume the emissivity is constant, which defeats the purpose of...

Carbonatite, from the Fen complex. This sample has a significant amount of apatite, generally arranged in radiating aggregations of elongated anhedral grains. While most grains of apatite are characteristically anhedral, there are some large well-developed euhedral crystals. Biotite...

I still have most/all of my college texts because I still (occasionally) consult them. To be sure, I consult them to reflect on how I (partially) learned the material then, so I can more effectively teach the material now. But I've also held onto books because that material is either not...

Jealous = me! This is one of the lenses I'd like to play with, for sure. It seems we are in a 'new golden era' of lens design, with Laowa offering some really off-the-wall lenses (10mm rectilinear full frame! Macroprobe!). Nikkor has recently introduced a 58/0.95 (for the Z mount). Sigh...

A second example of a carbonatite: Carbonatite. The literature on carbonatites is generally too advanced for me (for now), so I will simply quote some relevant sentences from a recent review (Annu. Rev. Earth Planet. Sci. 2022. 50:261–93) that may be open source: “Carbonatites are igneous...

Moving on from Fenites, I have several samples of carbonatites- the source magma for fenitization. Carbonatites are still the subject of active research, and I confess I'm way out of my depth. But, the optical properties of carbonates make the samples fairly photogenic. Here's the first one...

Thanks, but these don't address the problem that spatially varying hue causes. For my other lenses, I've had excellent results by placing the lens against a flat panel display monitor: there is no problem correcting for the spatial brightness. Again, as you can see from the image I posed, the...