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For the past 2% years, our team has been developing a unique photovoltaic concentrator array for collection and conversion of infrared laser light. This laser-receiving array has evolved from the solar-receiving Stretched Lens Array (SLA). The laser-receiving version of SLA is being developed for space power applications when or where sunlight is not available (e.g., the eternally dark lunar polar craters). The laser-receiving SLA can efficiently collect and convert beamed laser power from orbiting spacecraft or other sources (e.g., solar-powered lasers on the permanently illuminated ridges of lunar polar craters). A dual-use version of SLA can produce power from sunlight during sunlit portions of the mission, and from beamed laser light during dark portions of the mission. SLA minimizes the cost and mass of photovoltaic cells by using gossamer-like Fresnel lenses to capture and focus incoming light (solar or laser) by a factor of 8.5X, thereby providing a cost-effective, ultra-light space power system.

The stock light blockers that came with the quest pro do not work well with glasses leading me to design this variant which provides ample room and also includes a modular lens insert. The inserts are designed for the Zenni lenses found here: https://www.zennioptical.com/p/stainless-steel-round-eyeglass-frames-/5500?skuId=550021. The lens adapter module was spaced to accommodate those with 68-70mm IPD. You'll need four 4mm diameter magnets for the blocker and lens insert. They will magnetically attach to the sides of the quest. Models should be printed in the orientation provided with support set to > 65%. I used PLA for my prints. I'll be working on modifying the design to provide more coverage along the bottom.

I first designed the lens to fit the original CJ metal parking light housings. Then when I realized the stock bulb holders wouldn't properly hold the LED bulbs, I designed a housing that would use plastic bulb holders available on Amazon. I used these https://amzn.to/3djhbX8 but any that fits the hole should work. For best results print the lens open side up with no support and the housing open side down with support. I used transparent white ABS for the lens, and black ABS for the housings. https://youtu.be/mllpLnsGyZg https://youtu.be/6VDBZ6287NY

Try out our @EDC_LasVegas inspired Owl Lens and light up your sky. https://t.co/i8829471Sc #EDCLV2022 https://t.co/VpFZeNaPYd Source: https://twitter.com/Snapchat/status/1528073136264077312 Uploader: Snapchat

This paper is in the public domain in USA. Metadata comes from the CrossRef API, see full record in the source URL below.

"A Letter from the Rev. Nevil Maskelyne, A. M. Fellow of Trinity College, in the University of Cambridge, and F. R. S. to the Rev. Dr. Birch, Secretary to the Royal Society; Containing a Theorem of the Aberration of the Rays of Light Refracted Through a Lens, on Account of the Imperfection of the Spherical Figure" is an article from Philosophical Transactions (1683-1775), Volume 52 . View more articles from Philosophical Transactions (1683-1775) . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-105581

"A Letter from the Rev. Nevil Maskelyne, A. M. Fellow of Trinity College, in the University of Cambridge, and F. R. S. to the Rev. Dr. Birch, Secretary to the Royal Society; Containing a Theorem of the Aberration of the Rays of Light Refracted Through a Lens, on Account of the Imperfection of the Spherical Figure" is an article from Philosophical Transactions (1683-1775), Volume 52 . View more articles from Philosophical Transactions (1683-1775) . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-105581

For the past 2% years, our team has been developing a unique photovoltaic concentrator array for collection and conversion of infrared laser light. This laser-receiving array has evolved from the solar-receiving Stretched Lens Array (SLA). The laser-receiving version of SLA is being developed for space power applications when or where sunlight is not available (e.g., the eternally dark lunar polar craters). The laser-receiving SLA can efficiently collect and convert beamed laser power from orbiting spacecraft or other sources (e.g., solar-powered lasers on the permanently illuminated ridges of lunar polar craters). A dual-use version of SLA can produce power from sunlight during sunlit portions of the mission, and from beamed laser light during dark portions of the mission. SLA minimizes the cost and mass of photovoltaic cells by using gossamer-like Fresnel lenses to capture and focus incoming light (solar or laser) by a factor of 8.5X, thereby providing a cost-effective, ultra-light space power system.

after seeing the crazy costs of a very simple light housing for my custom built scale semi trailers I decided to try my hand at a set , I'm pleased how they turned out

We present a strong and weak gravitational lens model of the galaxy cluster MACSJ0416.1-2403, constrained using spectroscopy from the Grism Lens-Amplified Survey from Space (GLASS) and Hubble Frontier Fields (HFF) imaging data. We search for emission lines in known multiply imaged sources in the GLASS spectra, obtaining secure spectroscopic redshifts of 31 multiple images belonging to 16 distinct source galaxies. The GLASS spectra provide the first spectroscopic measurements for 6 of the source galaxies. The weak lensing signal is acquired from 884 galaxies in the F606W HFF image. By combining the weak lensing constraints with 15 multiple image systems with spectroscopic redshifts and 9 multiple image systems with photometric redshifts, we reconstruct the gravitational potential of the cluster on an adaptive grid. The resulting total mass density map is compared with a stellar mass density map obtained from the deep Spitzer Frontier Fields imaging data to study the relative distribution of stellar and total mass in the cluster. We find that the projected stellar mass to total mass ratio, $f_{\star}$, varies considerably with the stellar surface mass density. The mean projected stellar mass to total mass ratio is $\langle f_{\star} \rangle= 0.009 \pm 0.003 $ (stat.), but with a systematic error as large as $0.004-0.005$, dominated by the choice of the IMF. We find agreement with several recent measurements of $f_{\star}$ in massive cluster environments. The lensing maps of convergence, shear, and magnification are made available to the broader community in the standard HFF format.

This paper is in the public domain in USA. Metadata comes from the CrossRef API, see full record in the source URL below.

This is a 1.25" filter holder and light shroud for 1/3" cmos sensors and Chinese 25mm F1.4 c-mount lenses. The filter is securely sandwiched between the holder and the shroud.

We reformulate the transport equation which determines the size, shape and orientation of infinitesimal light beams in arbitrary spacetimes. The behaviour of such light beams near vertices and conjugate points is investigated, with special attention to the singular behaviour of the optical scalars. We then specialize the general transport equation to the case of an approximate metric of an inhomogeneous universe, which is a Friedmann metric `on average' with superposed isolated weak matter inhomogeneities. In a series of well-defined approximations, the equations of gravitational lens theory are derived. Finally, we derive a relative optical focusing equation which describes the focusing of light beams relative to the case that the beam is unaffected by matter inhomogeneities in the universe, from which it follows immediately that no beam can be focused less than one which is unaffected by matter clumps, before it propagates through its first conjugate point.

If the dark halo matter is primarily composed of MACHOs toward the lower end of the possible detection range ($ < 10^{-3}$ $M_{\odot}$) a fraction of the lens detection events should involve the lens crossing directly in front of the disk of the background star. Previously, Nemiroff (1987) has shown that each crossing would create an inflection point in the light curve of the MACHO event. Such inflection points would allow a measure of the time it took for the gravitational lens to cross the stellar disk. Given an independent estimate of the stellar radius by other methods, one could then obtain a more accurate estimate of the velocity of the lens. This velocity could then, in turn, be used to obtain a more accurate estimate of the mass range for the MACHO or disk star doing the lensing.

If the dark halo matter is primarily composed of MACHOs toward the lower end of the possible detection range ($ < 10^{-3}$ $M_{\odot}$) a fraction of the lens detection events should involve the lens crossing directly in front of the disk of the background star. Previously, Nemiroff (1987) has shown that each crossing would create an inflection point in the light curve of the MACHO event. Such inflection points would allow a measure of the time it took for the gravitational lens to cross the stellar disk. Given an independent estimate of the stellar radius by other methods, one could then obtain a more accurate estimate of the velocity of the lens. This velocity could then, in turn, be used to obtain a more accurate estimate of the mass range for the MACHO or disk star doing the lensing.

Excerpt: Doctor w/ his tiny light and lens peers where we can’t and says Hmmm. Or Jesus! De- pending. A poem or fragment, derived from Frank B. Ford 's Google Drive. Ford was an experimental poet and playwright, and it was his wish to have his work publicly archived online after his death. The file was automatically converted into an OpenOffice document from WordPerfect, AbiWord, Microsoft Word, or text, and was located at: ./myfiles/thisdesktop73009/doctlight.odt on the drive. The file date may not be accurate, especially if it is dated after 2022. ~18 words. Frank B. Ford (1932-2023): Works , Short CV , Obituary , Blog

"On the Structure of the Crystalline Lens in Fishes and Quadrupeds, as Ascertained by Its Action on Polarised Light" is an article from Philosophical Transactions of the Royal Society of London, Volume 106 . View more articles from Philosophical Transactions of the Royal Society of London . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-107534

David served as an @idf combat photographer, documenting intense battles and capturing the reality of war through his lens. On December 12, during an operation in Gaza, his unit was hit by an RPG, leaving him critically wounded, leading to the amputation of his leg, and marking the beginning of a new, unimaginable chapter in his life. David’s journey is a reminder that even in the darkest moments, determination, grit, and comradery light the way forward. Thank you, @sagidovev, for bringing us David's story and shining your light on others too!

David served as an @idf combat photographer, documenting intense battles and capturing the reality of war through his lens. On December 12, during an operation in Gaza, his unit was hit by an RPG, leaving him critically wounded, leading to the amputation of his leg, and marking the beginning of a new, unimaginable chapter in his life. David’s journey is a reminder that even in the darkest moments, determination, grit, and comradery light the way forward. Thank you, @sagidovev, for bringing us David's story and shining your light on others too!

The Marshall Space Flight Center (MSFC) has been developing a space deployable, lightweight membrane concentrator to focus solar energy into a solar furnace while remaining aligned to the sun. For an inner surface, this furnace has a cylindrical heat exchanger cavity coaligned to the optical axis; the furnace warms gas to propel the spacecraft. The membrane concentrator is a 1727 mm (68.00 in.) diameter, F/1.7 Fresnel lens. This large membrane is made from polyimide and is 0.076 mm (0.0030 in.) thick; it has the Fresnel grooves cast into it. The solar concentrator system has a super fast paraboloid reflector near the lens focus and immediately adjacent to the cylindrical exchanger cavity. The paraboloid collects the wide bandwidth and some of the solar energy scattered by the Fresnel lens. Finally, the paraboloid feeds the light into the cylinder. The Fresnel lens also possesses a narrow annular zone that focuses a reference beam toward four detectors that keep the optical system aligned to the sun; thus, occurs a refracting lens that focuses two places The result can be summarized as a composite Fresnel lens for solar concentration and alignment.

We revisit the effect of cosmological constant $\Lambda$ on the light deflection and its role in the cosmological lens equation. First, we re-examine the motion of photon in the Schwarzschild spacetime, and explicitly describe the trajectory of photon and deflection angle $\alpha$ up to the second-order in $G$. Then the discussion is extended to the contribution of the cosmological constant $\Lambda$ in the Schwarzschild-de Sitter or Kottler spacetime. Contrary to the previous arguments, we emphasize the following points: (a) the cosmological constant $\Lambda$ does appear in the orbital equation of light, (b) nevertheless the bending angle of light $\alpha$ does not change its form even if $\Lambda \neq 0$ since the contribution of $\Lambda$ is thoroughly absorbed into the definition of the impact parameter, and (c) the effect of $\Lambda$ is completely involved in the angular diameter distance $D_A$.

We study the relative alignment of mass and light in a sample of 16 massive early-type galaxies at z=0.2-0.9 that act as strong gravitational lenses. The sample was identified from deep multi-band images obtained as part of the Canada France Hawaii Telescope Legacy Survey as part of the Strong Lensing Legacy Survey (SL2S). Higher resolution follow-up imaging is available for a subset of 10 systems. We construct gravitational lens models and infer total enclosed mass, elongation, and position angle of the mass distribution. By comparison with the observed distribution of light we infer that there is a substantial amount of external shear with mean value $ = 0.12 \pm 0.05$, arising most likely from the environment of the SL2S lenses. In a companion paper, we combine these measurements with follow-up Keck spectroscopy to study the evolution of the stellar and dark matter content of early-type galaxies as a function of cosmic time.

When linearly polarized light impinging on a lens, it will reflect and refract along the lines curves resulting from the interception of a plane (plane of polarization) with a sphere (lens surface) maintaining the orientation of refraction and reflection in the plane of polarization. This effect is significant only looking at the lens laterally. Therefore, a lens acts as a lateral analyzer when we rotate the polarization plane of polarized light incident on the lens. Following this principle that in the spherical surface of a lens fit n circles of radius r, where n is inversely proportional to r, and each circle is a lens itself. Then if we shine a beam of light in one of these areas, the polarization phenomenon is expressed lateral side and diametrically opposite to where the incident linearly polarized light, the lens acting as a waveguide for the light beam polarized.

We characterize the interaction between a single atom or similar microscopic system and a light field via the scattering ratio. For that, we first derive the electrical field in a strongly focused Gaussian light beam, and then consider the atomic response. Following the simple scattering model, the fraction of scattered optical power for a weak coherent probe field leads to unphysical scattering ratios above 1 in the strong focusing regime. A refined model considering interference between exciting and scattered field into finite-sized detectors or optical fibers is presented, and compared to experimental extinction measurements for various focusing strengths.

The Marshall Space Flight Center (MSFC) has been developing a space deployable, lightweight membrane concentrator to focus solar energy into a solar furnace while remaining aligned to the sun. For an inner surface, this furnace has a cylindrical heat exchanger cavity coaligned to the optical axis; the furnace warms gas to propel the spacecraft. The membrane concentrator is a 1727 mm (68.00 in.) diameter, F/1.7 Fresnel lens. This large membrane is made from polyimide and is 0.076 mm (0.0030 in.) thick; it has the Fresnel grooves cast into it. The solar concentrator system has a super fast paraboloid reflector near the lens focus and immediately adjacent to the cylindrical exchanger cavity. The paraboloid collects the wide bandwidth and some of the solar energy scattered by the Fresnel lens. Finally, the paraboloid feeds the light into the cylinder. The Fresnel lens also possesses a narrow annular zone that focuses a reference beam toward four detectors that keep the optical system aligned to the sun; thus, occurs a refracting lens that focuses two places! The result can be summarized as a composite Fresnel lens for solar concentration and alignment.

Deliberately, but in error, the authors of AirSea Battle Concept (ASBC) did not define a specific desired end state to develop their plan to defeat People's Republic of China (PRC) aggression. Instead, the authors proposed a broad end state linked to a number of unnecessary and disadvantageous broad military objectives to keep the study as applicable to as many scenarios as possible. The predictable results from this construct were traditional obsolete and constrained ways to conduct the battle using virtually economically unconstrained traditional air and naval means. Commander, United States Pacific Command (CDRUSPACOM) should take heed of the author's accurate assessments of current warfighting imbalances in the theater, but begin planning by defining a clear end state with the most likely scenarios--maintaining the status quo of the disputed islands of Taiwan, the Spratley Islands, and the Senkaku islands. From this end state, CDRUSPACOM can identify and abandon unnecessary lines of operation such as active Ballistic Missile Defense (BMD) and mainland strikes using fighter aircraft, to free up resources for currently available technology which would enhance his ability to ensure a successful defense of the islands.

On the Structure of the Crystalline Lens in Fishes and Quadrupeds, as Ascertained by Its Action on Polarised Light. Brewster, D Philosophical Transactions of the Royal Society of London (1776-1886). 1816-01-01. 106:311–317

p. cm

"On the Structure of the Crystalline Lens in Fishes and Quadrupeds, as Ascertained by Its Action on Polarized Light. [Abstract]" is an article from Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London, Volume 2 . View more articles from Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-109862

Studio photography is a common career path for aspiring photographers and students but the professional and commercial nature of the field makes it a challenging area to break into. Whilst other introductory books on the subject are often bogged down with too much technical detail or too many 'show-off' shots, Studio Photography: Essential Skills offers a practical and accessible guide to the fundamental techniques for successful studio photography. Whether photographing a person or a product, you need control over the light, mood and look to arrive at the perfect result for a particular assignment. This book takes a commercial and creative approach and considers the important elements of lighting, exposure, capture, art direction and the studio setting to ensure a successful shoot. With a clearly structured learning approach and a wide variety of activities and assignments to inspire and engage you, this is an informative, stimulating guide to the basics. Broaden your skills and increase your earning potential with Studio Photography: Essential Skills !

Studio photography is a common career path for aspiring photographers and students but the professional and commercial nature of the field makes it a challenging area to break into. Whilst other introductory books on the subject are often bogged down with too much technical detail or too many 'show-off' shots, Studio Photography: Essential Skills offers a practical and accessible guide to the fundamental techniques for successful studio photography. Whether photographing a person or a product, you need control over the light, mood and look to arrive at the perfect result for a particular assignment. This book takes a commercial and creative approach and considers the important elements of lighting, exposure, capture, art direction and the studio setting to ensure a successful shoot. With a clearly structured learning approach and a wide variety of activities and assignments to inspire and engage you, this is an informative, stimulating guide to the basics. Broaden your skills and increase your earning potential with Studio Photography: Essential Skills !

On the Structure of the Crystalline Lens in Fishes and Quadrupeds, as Ascertained by Its Action on Polarized Light. Brewster, D Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London (1800-1843). 1815-01-01. 2:50–51

A Letter from the Rev. Nevil Maskelyne, A. M. Fellow of Trinity College, in the University of Cambridge, and F. R. S. to the Rev. Dr. Birch, Secretary to the Royal Society; Containing a Theorem of the Aberration of the Rays of Light Refracted Through a Lens, on Account of the Imperfection of the Spherical Figure. Maskelyne, N Philosophical Transactions (1683-1775). 1761-01-01. 52:17–21

"¡Vendedores, Presente!", a Lens creation by Ruben Ochoa in partnership with @LACMA, can be experienced in MacArthur Park and sheds light on the critical role of street vendors in L.A. Learn more about the Monumental Perspectives initiative: https://t.co/iuQFDU1uch https://t.co/jwZVYCiQn7 Source: https://twitter.com/Snapchat/status/1382804647509901318 Uploader: Snapchat