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Over the past several hundreds of years, optical systems (telescopes, microscopes, eyeglasses, cameras, etc.) have formed their optical image on the human retina, photographic plate, or film. The birth of photodetectors dates back to 1873 when Smith discovered photoconductivity in selenium. Progress was slow until 1905, when Einstein explained the newly observed photoelectric effect in metals, and Planck solved the blackbody emission puzzle by introducing the quantum hypothesis. Applications and new devices soon flourished, pushed by the dawning technology of vacuum tube sensors developed in the 1920s and 1930s, culminating in the advent of television. Zworykin and Morton, the celebrated fathers of videonics, on the last page of their legendary book Television (1939) concluded that: “when rockets will fly to the moon and to other celestial bodies, the first images we will see of them will be those taken by camera tubes, which will open to mankind new horizons.” Their foresight became a reality with the Apollo and Explorer missions. Photolithography enabled the fabrication of silicon monolithic imaging focal planes for the visible spectrum beginning in the early 1960s. Some of these early developments were intended for a videophone, and other efforts were for television cameras, satellite surveillance, and digital imaging. Infrared imaging has been vigorously pursued in parallel with visible imaging because of its utility in military applications. More recently (1997), the charged-coupled device (CCD) camera aboard the Hubble Space Telescope delivered a deep-space picture, a result of 10 day’s integration, featuring galaxies of the 30th magnitude—an unimaginable figure, even for astronomers of our generation. Thus, photodetectors continue to open to humanity the most amazing new horizons.

We investigated the specific features of two diffraction schemes for a widely divergent X-ray beam that use a circular diaphragm 30–50 μm in diameter as a point source of characteristic radiation. In one of the schemes, the diaphragm was set in front of the crystal (the diaphragm-crystal (d-c) scheme); in the other, it was installed behind the crystal (the crystal-diaphragm (c-d) scheme). It was established that the diffraction image in the c-d scheme is a topographic map of the investigated crystal area. In the d-c scheme at L = 2l (l and L are the distances between the crystal and the diaphragm and between the photographic plate and the diaphragm, respectively), the branches of hyperbolas formed in this family of planes (hkl) by the characteristic Kα and Kβ radiations, including higher order reflections, converge into one straight line. It is experimentally demonstrated that this convergence is very sensitive to structural inhomogeneities in the crystal under study.

A hologram is a tool for shaping the amplitude and the phase of a light wave. Shaping the amplitude distribution is easy, one way is by a photographic plate, another way is by binary pixels as used in "half-tone printing”. The phase distribution can be shaped by RE-fraction on a thin film of variable thickness, or by DIF-fraction on a diffraction grating that has been distorted on purpose.

For image formation, basically only one condition needs to be fulfilled: The rays which originate at “object points” must be limited to a small spatial opening angle ω by passing through an aperture (Sect. 16.1) on their way to the image plane (e.g. a projection screen or a photographic plate). In Fig. 17.1a, the aperture B is a small round opening (pinhole camera!); in Fig. 17.1b, it is a small planar mirror. In both cases, as a suitable object to be imaged, we have chosen an arrow or letter made with small light bulbs.

The results of a new reduction of 1545 photographic observations of 14 selected asteroids obtained with the Normal Astrograph of the Pulkovo Observatory from 1948 to 1990 are presented. Photographic plates stored in the archive of the observatory were digitized with a general purpose flatbed scanner using a specially developed technique. The accuracy of the reduction of photographic plates is measured. The UCAC3 catalogue has been used as a reference. Residual differences between coordinates of stars in the reference catalogue are used to analyze and tacking into account obtained instrumental systematic errors. Equatorial coordinates of 1378 individual observations of target asteroids are obtained. They are compared with the results of the reduction of the material made earlier. Among the objects of the background, positions of 1475 stars with large proper motions from the LSPM catalogue are measured.

The results of a new reduction of positional observations of the asteroid Ceres are presented. The observational material was obtained in the State Astronomical Institute using the wide-angle astrograph AFR-1. The interval of photographic observations is 30 years, from August 1956 to May 1986. Measurements of the relative coordinates of stars and the asteroid were submitted electronically. A new model of reduction and a modern catalogue of stellar positions, the reference catalogue Tycho, were used in the calculations. Right ascension and declination of the asteroid at the time of observations were obtained from the International Celestial Reference Frame. The estimate of the mean square error of one measurement is 0.25″.

A method for implementing the diffraction of a widely divergent characteristic X-ray beam from a standard X-ray tube with a linear focal spot was improved. X rays, passing through a diaphragm 30 μm in diameter, diffract from a crystal adjacent to the diaphragm. The crystal, together with a photographic plate, rotates around the axis perpendicular to the plate. It is shown that the diffraction image is a set of hyperbolas in this case. The equations of the hyperbolas are obtained and investigated. A method for interpreting the diffraction images in the case of small crystal asymmetry is proposed.

In phase-shifting digital holography, a hologram is usually recorded on a CCD sensor instead of a photographic plate. The complex amplitude of the object is analyzed from the phase-shifted holograms obtained by shifting the phase of the reference beam. The reconstructed image can be calculated from the complex amplitudes of the hologram [1].

Since the time of Isaac Newton (1642–1727) scientists and astronomers have been trying to come to terms with the fact that all lenses produce a spectrum. Newton’s early experimentation with prisms incorrectly led him to conclude that a glass lens would always present this spectrum of light as a chromatic aberration and was therefore of limited value to astronomical telescopes. If nothing else, this encouraged him to work on reflective optics and the “Newtonian” telescope was born.

ArgumentThis article explores the entangled histories of three imaging techniques in early nineteenth-century British physical science, techniques in which a dynamic event (such as a sound vibration or an electric spark) was made to leave behind a fixed trace on a sensitive surface. Three categories of “sensitive surface” are examined in turn: first, a metal plate covered in fine dust; second, the retina of the human eye; and finally, a surface covered with a light-sensitive chemical emulsion (a photographic plate). For physicists Michael Faraday and Charles Wheatstone, and photographic pioneer William Henry Fox Talbot, transient phenomena could be studied through careful observation and manipulation of the patterns wrought on these different surfaces, and through an understanding of how the imaging process unfolded through time. This exposes the often-ignored materiality and temporality of epistemic practices around nineteenth-century scientific images said to be “drawn by nature.”

As a result of the cooperation between the Sofia Sky Archive Data Center (Bulgaria) and Bamberg Observatory (Germany), Royal Observatory of Edinburgh (UK), Konkoly Observatory (Hungary), Strasbourg Observatory, Institute of Astronomy in Cambridge (UK), etc., a programme for investigation of the long-term behaviour of the Pleiades active dwarf stars (in particular, flare stars) is in progress. Existing plates in the Pleiades are found in different European plate archives, made since the end of the nineteenth century, by the searching tool of the wide-field plate database (http://www.skyarchive.org), which provides detailed information for astronomical plate archives all over the world, as well as for plates themselves. We investigate the Pleiades flare stars (UV Cet-type stars) included in the flare Stars database and identified in the USNO A2.0 catalogue. 68 Pleiades plates are already digitized with different scanning machines such as PDS 1010 (Sofia), PDS 2020 (Munster), SUPER COSMOS (Edinburgh), APM (C...

The birth of astrophotography is discussed followed by rapid advances over several decades in both the types of objects imaged and the technical changes developed to meet the challenges of imaging those objects.

Synchrotron X–ray reticulography measures lattice–plane orientation variations point by point on the crystal with microradian resolution capability. A fine–scale X–ray–absorbing mesh placed close to the crystal in the back–reflected diffracted beam of ‘white’ X–rays splits the beam into an array of microbeams whose direction differences are measured from the mesh–bar shadow shifts that result from controlled changes of the distance between the mesh and the recording high–resolution photographic plate. In the present work, lattice tilts were measured on either side of a growth–sector boundary outcropping at the surface of a single–crystal synthetic diamond cut and polished parallel to (110) in which the displacements and strains due to lattice–parameter mismatch at coherent growth–sector boundaries have been analysed in part I. Attention was concentrated on a crystallographically well–defined planar segment of a boundary separating two sectors, each of uniform, but significantly differing, concentration of substitutional nitrogen impurity, and for which the anisotropic elasticity theory of part I provided quantitative relations between the lattice–parameter relative difference, Δa/ā, and the lattice tilts due to coherency strains at the boundary. This enabled a novel method for determining Δa/ā to be realized, using reticulographic measurements of tilts of near–surface lattice planes alone. The paper explains the reticulographic technique fully. Factors affecting the quality and reliability of reticulographic records are examined in detail. For the growth sectors concerned, the reticulographic measurement Δa/ā = (1.10 ± 0.10) × 10−5 is in accord with an earlier finding by synchrotron X–ray double–crystal diffractometry, slightly revised as recommended in part I, Δa/ā = (1.20 ± 0.07) × 10−5. The closeness of the findings by two quite different methods confirms the conclusion from X–ray topography that the growth–sector boundary was free from misfit dislocations compensating the lattice–parameter mismatch. On mismatch boundaries in crystals too highly absorbing for transmission X–ray topography, such comparisons of reticulographic and diffractometric measurements would reveal information otherwise inaccessible by non–destructive methods.

The method of holographic interferometry with the increased sensitivity was applied for measurements of height of nano-steps (from 10 nm and higher) with standard uncertainty about 0.5 nm. The increasing of sensitivity is obtained by interference of waves with mutually complex conjugated phases. Index Terms – liquid crystal, spatial light modulator, dynamic holography, holographic intereferometry. The technique of interferogram magnification was invented at the early stages of holographic interferometry (see, for instance, [1]). Its idea of this two-stage method is as follows. On the first stage the interferogram was recorded on photographic plate and processed. The processed pattern was treated as the amplitude plane hologram. On the magnification stage it was reonstructed by illumination by a plane reference wave and numerous beams, corresponding to various diffraction orders were thus obtained. Holographic magnification of the interferogram was produced by registration of interference pattern, produced by an arbitrary pair of these beams, most often – by the beams, corresponding to one and the same diffraction orders m of two signs. Combining the beams with m = ±1, ±2 or ±3 provides increase of fringe deformations in 2, 4 or 6 times correspondingly. Such a procedure, of course, adds nothing to the information, contained in the interference pattern, but in many cases, especially when the fringe deformations are small, it makes it possible to decipher the information in a much faster and simpler way. The progress in digital record and numerical processing of interferometric information has reduced the need in such technique, but the recent progress in dynamic holography with the use of matrix phase modulators returns it to agenda. Now similar approaches can be of use in the case of realtime interferometery, mass production etc. One can also introduce in the routine various digital techniques like change of spatial carrier frequency, filtration of distortions, imposed by interferometer elements etc. We report the results of experimental evaluation of such approach with the use of digital holography in matrix liquid crystal spatial light modulator Holoeye LC-2002. Fig. 1 Master-hologram (interferogram, above) and magnified interferogram (multiplication 4x, below). Prof. Vladimir Yu.Venediktov thanks the Ministry of Science and Education of Russian Federation for the funding through the leading scientists’ support program. The authors are grateful to the Russian scientific foundation for funding through the grant # 14-19-00693.

Underwater photography first appeared on the screen of modern visual consciousness at the ornate Palace of Optics at the Paris Universal Exhibition of 1900. Far from being a benign distraction, this new medium revealed optics itself to be in a state of suspended animation. A cursory inventory of the Palace's contents-a reading of its architectural cross section, evenreveals the outline of the situation. Planned as a working observatory, the Palace housed a colossal refracting telescope that promised to produce the "largest, brightest, and most distinct" photographs possible of the celestial vault.' Representing the leading edge in resolution, the telescope was part of an international project to catalogue the night sky. Indeed, photography had become the reason for, and not only the result of, new advances in optics. What such a claim meant for the progress of vision, however, is another question. The fact that photography represented "a different kind of retina than the human eye" had already been noted by one prominent astronomer, who reported that certain nebulae visible through a telescope failed to expose a photographic plate, and others that made a photographic impression could not be seen by the eye.2 That this fact was interpreted as an argument against the "blindness" of animals living in the "pretended darkness" of the ocean's depths points to an unusual space that had opened up between vision and visuality.3 What appeared on the screen at the Palace was the notion of a visual milieu.

An experiment is described in which two semi-transparent reticles and a photographic plate separated by several centimeters are illuminated by a monochromatic point source in a typical in-line configuration. The resulting shadowgram is a hologram that contains information from both reticles. Illuminating this complex hologram with a similar point source with the reticles removed produces reconstructed real images at two separate locations whose coordinates are predicted from simple theory, and also produces virtual images of the reticles at their original coordinates. This experimentally confirms the three-dimensional capability of an in-line hologram. As imaging devices such as charge-coupled device sensors become cheaper and of higher resolution, a simple demonstration of this aspect of holograms, which can be projected to an audience, can be observed by sliding the image sensor along the axis.

Reflection type high-speed holographic microscopy is applied to photograph the bifurcation of fast propagating cracks in PMMA. The cracks are of the opening mode. Spatial resolution is more than 180 lines/mm, frame interval is 5μs and the number of frames is three. A crack at bifurcation is recorded as three successive holograms on one photographic plate by means of angle-multiplexing holography. Lens assisted reconstruction method is used to reconstruct separately the three crack images from the holograms. The reconstructed crack images are magnified and photographed through a conventional microscope. The photographs show that, at bifurcation, several crack tips are running simultaneously in a small region about 1 mm in diameter. And also shown is dynamic three dimensional behavior of crack front edges or microcracks at bifurcation.

We analyze the conditions for formation in diffusely scattered fields of a fringe-shift hologram characterizing spherical aberration of a positive test lens or objective with spatial filtration of the diffraction field performed at the recovery of a double-exposure Gabor hologram.

As with virtually all photographic plate material, the astrograph plates from which the Southern Proper Motion (SPM) catalog is being compiled suffer from magnitude-dependent systematic shifts in the image positions, i.e., a magnitude equation. If left uncorrected, these would adversely affect both the primary goals of the SPM catalog, the absolute proper motions, and the faint secondary reference frame. Using the diffraction-grating images present on the plates, a procedure is adopted that allows a spatially variant magnitude equation correction to be derived individually for each SPM plate. Application of the method to ~120 SPM fields, primarily around the south Galactic pole and the -30° and -35° declination zones, demonstrates its effectiveness. Indeed, the method proves superior, in the case of the SPM, to a direct calibration of the magnitude equation using the newly available Tycho Catalogue. The result of the diffraction-grating technique is final SPM positions and proper motions that are largely magnitude equation–free, as verified by numerous internal and external checks.

We present trigonometric, photometric, and photographic distances to 1748 southern ($\delta \leq$0$^\circ$) M dwarf systems with $\mu \ge$ 0\farcs18 yr$^{-1}$, of which 1404 are believed to lie within 25 parsecs of the Sun. The stars have 6.67 $\leq$ $V_J$ $\leq$ 21.38 and 3.50 $\leq$ ($V_J-K_s$) $\leq$ 9.27, covering the entire M dwarf spectral sequence from M0.0V through M9.5V. This sample therefore provides a comprehensive snapshot of our current knowledge of the southern sky for the nearest M dwarfs that dominate the stellar population of the Galaxy. Roughly one-third of the 1748 systems, each of which has an M dwarf primary, have published high quality parallaxes, including 179 from the RECONS astrometry program. For the remaining systems, we offer photometric distance estimates that have well-calibrated errors. The bulk of these ($\sim$700) are based on new $V_JR_{KC}I_{KC}$ photometry acquired at the CTIO/SMARTS 0.9m telescope, while the remaining 500 primaries have photographic plate distance estimates calculated using SuperCOSMOS $B_JR_{59F}I_{IVN}$ photometry. Confirmed and candidate subdwarfs in the sample have been identified, and a census of companions is included., Comment: accepted by The Astronomical Journal on 25 July, 2014; 75 pages of tables, 11 figures

The formation of a lateral-shear speckle interference pattern in bands of infinite width in two-exposure recording of the Fourier speckle pattern of a ground-glass screen by a negative lens is analyzed. It is demonstrated theoretically and experimentally that an interference pattern is localized in the Fourier plane during reconstruction; that patterns is characterized by axial wave aberrations of the lens and optical system used in the channel illuminating the ground-glass screen, with twice the sensitivity for a fixed lateral shear. In the particular case when the lens is in the plane of the ground glass screen the interference pattern characterizes the axisymmetric wave front aberrations.

Astrometry in the solar system made more progress during the past ten years than it did during the seven or eight decades before. In fact, the development of large refractors with micrometers, and after the improvement of the photographic technique, allowed one to get very accurate positions at the end of the 19th century. After that, relatively little progress was made. Astronomers faced several difficulties: first, was the poor sensitivity of the photographic plates leading to long exposures and therefore to low accuracy for faint objects; second, was the poor quality of the catalogues of stars which depended upon a very small number of available astrometric reference stars.New receptors appeared around the 1950, such as electronic cameras or T.V. tubes. But, most of these new receptors were not interesting for astrometry, mainly because of the field of view – which was too small – and of the difficulty of using such receptors. However, the development of a new technique based upon the CCD targets changed most of the astrometric observational programs. In fact, CCD receptors were made for small fields, but the CCDs were easy to use; the images were numerical, allowing processing by computers, and the sensitivity was much more important. Because of that, the accuracy increased and relative astrometry was developed. The recent development of new catalogues, such as the Guide Star Catalogue and Tycho, permits astronomers to reduce small fields, which was not possible earlier.

Astronomers were among the first to embrace the digital era. In the early 1970s, long before jpegs and gifs, and digital cameras in the hands of everyday consumers, astronomers were spending huge portions of their budgets on CCD (charge couple device) technology. Many claim that the development of the CCD was the second-most important technological breakthrough in astronomy (second only to the invention of the telescope itself). For astronomers, the advantage of digital imaging is far greater than convenience. Once armed with the CCD, and its ability to quantitatively measure the intensity of incoming light, to effectively count photons one by one; they dropped the photographic plate like a hot potato.

The study of the passage of electricity through gases had lagged behind the corresponding study on metals and liquids. Faraday himself had engaged in research on electrical discharges in gases as early as 1838 but was hampered by the inefficiency of his vacuum pumps.

A polymer alloy film on a photographic plate (ILFORD, Q-plate) was exposed to the dispersed soft X-rays in the wavelength region between 8.1 nm and 33.6 nm. The image on Q-plate was magnified by an optical microscope. In the microscopic images of the polymer alloy containing silicon, circular spots of about 30 μm in diameter scattered in a matrix was observed with certain wavelengths of soft X-rays. The image contrast between the spots and the matrix was reversed at around the wavelengths of 12.6 nm and 17.5 nm. This reversal of contrast suggests that these circular spots, or islands, are silicon-rich phases because the L-absorption edge of silicon is 12.3 nm.

The development of emission spectroscopy and its application is closely connected with the analysis of metals and related materials. Therefore, this short review mainly will pay homage to metal analysing laboratories. Some highlights of the 170-year period of development will be given here. The examples of solid sampling techniques applied to the analysis of metals or related oxides in the micro range have originated in the author's laboratory over the past 30 years. Thirty years ago, when ICP emission spectroscopy was first described and atomic absorption spectrometry was introduced for practical analysis, very precise and accurate emission spectrographic methods were being used successfully. Micro-sampling of solids took place by arc or spark vaporization including laser ablation, and detection was achieved by photographic plate exposure. After closure of these sections of analytical laboratories and retirement of the very experienced operators, a long period of development was started, enhanced by the new techniques of AAS and ICP spectrometry. The result of this development makes the two techniques available for application to microanalysis, together with the old spectrographic methods. ICP is chiefly of interest because of its multielement capability. The success of the 30-year development of emission spectroscopic methods related to direct microsampling is characterized by obtaining a greater quantity of precise data in a shorter time but no improvement of accuracy can be seen up to now.

The history of astrometry, the branch of astronomy dealing with the positions of celestial objects, is a lengthy and complex chronicle, having its origins in the earliest records of astronomical observations more than two thousand years ago, and extending to the high accuracy observations being made from space today. Improved star positions progressively opened up and advanced fundamental fields of scientific enquiry, including our understanding of the scale of the solar system, the details of the Earth's motion through space, and the comprehension and acceptance of Newtonianism. They also proved crucial to the practical task of maritime navigation. Over the past 400 years, during which positional accuracy has improved roughly logarithmically with time, the distances to the nearest stars were triangulated, making use of the extended measurement baseline given by the Earth's orbit around the Sun. This led to quantifying the extravagantly vast scale of the Universe, to a determination of the physical properties of stars, and to the resulting characterisation of the structure, dynamics and origin of our Galaxy. After a period in the middle years of the twentieth century in which accuracy improvements were greatly hampered by the perturbing effects of the Earth's atmosphere, ultra-high accuracies of star positions from space platforms have led to a renewed advance in this fundamental science over the past few years., 52 pages, 14 figures. To appear in The European Physical Journal: Historical Perspectives on Contemporary Physics

Photographic images are valuable data resources for studying long term changes in the solar magnetic field and its influence on the Earth's climate and weather. We digitized more than 100 years of white light images stored in photographic plates and films that are available at Kodaikanal observatory starting from 1904. The digitized images were calibrated for relative plate density and aligned in such a way that the solar north is in upward direction. A semi-automated sunspot detection technique was used to identify the sunspots on the digitized images. In addition to describing the calibration procedure and availability of the data, we here present preliminary results on the sunspot area measurements and their variation with time. The results show that the white-light images have a uniform spatial resolution throughout the 90 years of observations. However, the contrast of the images decreases from 1968 onwards. The images are circular and do not show any major geometrical distortions. The measured monthly averaged sunspot areas closely match the Greenwich sunspot area over the four solar cycles studied here. The yearly averaged sunspot area shows a high degree of correlation with the Greenwich sunspot area. Though the monthly averaged sunspot number shows a good correlation with the monthly averaged sunspot areas, there is a slight anti-correlation between the two during solar maximum The Kodaikanal data archive is hosted at http://kso.iiap.res.in. The long time sequence of the Kodaikanal white light images provides a consistent data set for sunspot areas and other proxies. Many studies can be performed using Kodaikanal data alone without requiring intercalibration between different data sources., Comment: 9 pages, A&A(accepted)

Elliptical Bragg-Fresnel multilayer lenses (BFML), designed and fabricated at the Institute of Microelectronic Technology (Russian Academy of Science) have been used for two-dimensional focusing of the white X-ray synchrotron beam at LURE (Orsay France). For two fixed beam energies (8 keV and 12.4 keV), the spot size produced was approximately 1 μm as determined from a high resolution photographic plate. A fluorescence X-ray scanning microprobe based on these BFML lenses was also tested. The transmitted signal registered during the scan of a test object shows less than 1 μm resolution with 8 keV output photon energy. 2D scanning images with submicron resolution of test objects in transmission mode at 8 keV and 12.4 keV beam energies are presented.

Matrix and linear interference patterns formed in emulsion layers of transmission holograms are considered. Boundary effects are observed between matrix and linear interference patterns, as well as between a linear interference pattern and the unexposed part of a hologram.

Thomson’s first idea for how the atom combined positive and negative electrical charge – known as the plum pudding model – was that it consisted of a positively charged lump of mass studded through with the negatively charged electrons. Experiments using a kind of particle accelerator would later prove this model wrong – but here the accelerator was not man made.

For the measurement of vibrations using double-pulse techniques, pulses separations between 1 and 1000 microseconds are necessary. Until now double-pulsed holographic interferometry has been extensively used to measure vibrations. This method has the disadvantage that it needs the recording and the reconstruction of a hologram. For the recording a photographic plate or a thermo-plastic camera is usually used. The hologram is then reconstructed usually with a continuous laser and viewed with a CCD camera. This process is time consuming. Double pulsed ESPI [1] enables to obtain correlation fringes corresponding to the displacement without recourse to any form of photographic processing and plate relocation.

Some ways to increase the sensitivity of high-resolution silver halide materials in the spectral range of 1.06–1.3 μm are considered. The sensitivity is increased by four orders of magnitude, and the range of spectral sensitivity is expanded to 1.7 μm.

The publication of Kirchhoff’s and Bunsen’s work brought the awareness of the spectroscope, and what it could reveal, to a wider audience, including astronomers. The obvious question was, how could this new instrument be used to analyze the light from the Sun and stars?

When normal laser holographic technique is applied to subjects in strong incoherent illumination, an additional darkening of the photographic plate due to the incoherent light is introduced. Effects of the darkening on the signal-to-noise ratio of the reconstructed image are analyzed using a simplified model for photographic plate characteristics. Optimum values of the fraction of laser light used as reference, plate exposure, and S/N are obtained. Reconstructed images of reasonable contrast and pictorial quality have been obtained for 3-D subjects illuminated with substantial incoherent light intensity in addition to the laser light.

Two and three primary colors derived from an He-Ne gas laser and an argon gas laser were employed in recording and reconstructing holograms. For the tricolor case it is possible to reconstruct a three-dimensional multicolor image which possesses almost all the natural hues of the original object. Each wavelength generates an independent fringe system that is recorded on a photographic plate with a thick emulsion that constitutes a three-dimensional recording medium. In reconstruction, each fringe system diffracts light in a manner satisfying the Bragg relation for a particular reconstructing wavelength. If the reconstruction wavelengths are the same as the original wavelengths used to record the fringe systems, the result is a multicolor reconstruction possessing few or no ghost images. In our experiments, the angle between the object beam and the reference beam was greater than 100 degrees , and the photographic plates were oriented so that the fringe surfaces were approximately perpendicular to the emulsion surfac This minimized the deleterious effects of single-color, ghost image formation and shrinkage during development. Finally, a method of synthesizing multicolor scenes using a multiple-exposure recording with one wavelength and reconstructing with several wavelengths is described.

Over the period of three hundred years leading up to the detection of the first parallax in 1838, the measurement of star positions had actually followed two somewhat separate branches. The first of these concentrated on the measurement of parallax, exemplified by the pioneering works of Bradley and Bessel.

A catalogue of 180 stellar associations in M81 has been compiled using two plates taken with the 2-m Rozhen telescope. The catalogue gives the positions of associations, their mean angular sizes and H II identifications. It is found that the frequency distribution of associations in M81 is similar to that in M33, and their characteristic length is ≃ 80 pc. These small dense groups are real OB associations because their stellar contents are the same as those in the Galaxy. Most of the associations selected in the present work coincide with H II regions

We report the recording of optical holograms in both holographic plate films and thermoplastic film using a commercial single-mode laser diode having a wavelength of 787.3 nm. Holographic film characteristics and laser-diode coherence length studies as well as experimental results with simple plane-wave holograms are discussed.

Image-stabilization systems are used in many applications, ranging from astronomical imaging to optical communications systems. Despite the differences in application, many tip-tilt systems have a great deal in common because they make use of a wavefront sensor, a controller, and a wavefront compensator. The differences between the systems are often in the selection of the individual components used to make up the final system. Previous chapters identified the function of the components and demonstrated how they are used together. This chapter provides an overview of several prominent observatory and telescope projects that use image-stabilization systems. The image-stabilization instrumentation identified here is often included as part of large adaptive optics and long-baseline interferometric systems. The project-specific material presented here was taken from the literature and publications about the projects. References are provided so readers can follow up on projects that they find particularly interesting. Imaging through atmospheric turbulence has provided a number of challenges for astronomical observers. As the first large telescopes became available in the first quarter of the 20th century, observers using long exposures on photographic plates faced significant challenges in keeping the stellar images in fixed position on spectroscope slits or on imaging plates. On many of the early large telescopes, the position of the star on the photographic plate was controlled by visual guiding; that is, the observer watched the position of a star in a high magnification eyepiece attached to the plate holder and adjusted orthogonal positioners to keep the star fixed in a high-magnification eyepiece, and thus on the plate. As observations could literally take all night, this was not a great assignment.

In 1896 Henri Becquerel discovered that compounds containing uranium emit radiations that can penetrate opaque paper and even thin sheets of metal and cause photographic plates to darken. Like x-rays, these emissions ionized air and caused electroscopes to discharge, but unlike x-rays, they occurred without any external source of excitation. Becquerel’s student, Marie Curie, named this spontaneous emission of ionizing radiation “radioactivity.”

Most instruments employed for astronomical observations are designed primarily to increase the intensity of illumination on the surface of an image-recording device, be it a conventional photographic plate, a sophisticated electronic detector, or merely the human eye. This may be achieved by enhancing the light-collecting area or by sharper imaging, with the aims of improved angular resolution in order to separate closely adjacent objects and high light-gathering power in order to clearly pick out faint objects. There is no all-round, “universal” instrument available that satisfies all of these requirements simultaneously. Rather, an observing instrument is optimized for a specific purpose and is often named after a particular type of construction or observational mode (e.g., zenith telescope, transit circle, binoculars, rich-field telescope, coronograph, astrograph or Schmidt camera).

Sensitivity, dynamic range, resolution, precision and response time of a channeltron electron multiplier array and of conventional detectors (Faraday cage, electron multiplier and photographic plate) are compared. The properties of the detection methods differ greatly and each method is superior in some aspect. Capabilities of channel plate detection and features of channel plate mass spectra are discussed.

An artificial screen has been constructed to encode spatial information of simple transparent objects. The constructed encoder is composed of a matrix of small strips, photographed several times on a high resolution film to obtain strips of nearly ten times the average grain size of natural speckles. A second encoder has been constructed by recording a natural speckle pattern on a photographic plate which has gone through a continuous shift during the time of exposure in a specific direction, forming an elongated speckle pattern. A comparison between the results obtained using the two encoders has been presented.

The contrast degradation due to tilt between exposures limits the amount of tilt, the number of fringes and the spatial resolution. The effect was derived quantitatively and verified experimentally. Mutual influences between system parameters cause ambiguity in the measurement results. The main effects are imaginary displacement resulting from combined deflection and initial slope, and imaginary strain resulting from deflection. These effects were demonstrated experimentally. Formulas were developed that enable the designer of the experiment to choose the desirable parameters of the set-up. They point out the difficulties in using the method in ‘field measurements’, primarily because of the finite dimensions of the lens and the photographic plate.

The StarScan machine at the U.S. Naval Observatory (USNO) completed measuring photographic astrograph plates to allow determination of proper motions for the USNO CCD Astrograph Catalog (UCAC) program. All applicable 1940 AGK2 plates, about 2200 Hamburg Zone Astrograph plates, 900 Black Birch (USNO Twin Astrograph) plates, and 300 Lick Astrograph plates have been measured. StarScan comprises of a CCD camera, telecentric lens, air-bearing granite table, stepper motor screws, and Heidenhain scales to operate in a step-stare mode. The repeatability of StarScan measures is about 0.2 micrometer. The CCD mapping as well as the global table coordinate system has been calibrated using a special dot calibration plate and the overall accuracy of StarScan x,y data is derived to be 0.5 micrometer. Application to real photographic plate data shows that position information of at least 0.65 micrometer accuracy can be extracted from course grain 103a-type emulsion astrometric plates. Transformations between "direct" and "reverse" measures of fine grain emulsion plate measures are obtained on the 0.3 micrometer level per well exposed stellar image and coordinate, which is at the limit of the StarScan machine., 24 pages, 8 figures, accepted for PASP

In this article principles of operation of a coherent optical image correlator based on a well know optical joint transform correlator are examined. Theoretical predictions and experimental data for of the optical image correlator with a holographic filter recorded on a thin holographic photographic plates PFG - 01 are analyzed. Results of the operation of the dynamic joint transform correlator on the basis of cadmium fluoride crystal, CdF2, with bistable impurity centers are demonstrated. Calculated and experimental correlation peak intensity dependencies with the scale and angular mismatch between an observed and reference objects for static and dynamic joint transform correlators are compared. Tangram figures were used as a test images. In the paper all computations were performed by use of MATLAB 7.0.1 mathematical program.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In Particle Image Velocimetry the analysis of the multi-exposed photographic plate can be carried out either by means of the Young's fringe analysis or by a direct technique. With this second approach the image of each interrogation area, enlarged by a microscope, is recorded by means of a digital image acquisition system. After some preliminary filtering operations the digitized image can be analyzed with numerical tools. In this paper a review of the digital techniques used in the analysis of these images is carried out. Both twodimensional and onedimensional techniques are analyzed and the problems involved in their use are discussed.

SUMMARY A new technique based on holographic interferometry has been developed for measuring crustal deformations. The holographic recording system, consisting of an He-Ne gas laser and associated optical elements, was first installed in a tunnel at the Amagase Crustal Movement Observatory in 1984. Tunnel deformations caused by tidal and tectonic forces have been precisely determined using the ‘real-time’ technique of holographic interferometry. In this procedure, a hologram of the tunnel wall within a section 1-2 m in diameter is directly recorded on a photographic plate and then the plate is carefully reset in the position at which the hologram was taken. When the reconstructed image of the hologram is superimposed on the current image of the tunnel wall, many interference fringes can be seen through the hologram. The fringe displacement, formed by the deformation of the tunnel, is continuously recorded on a video-cassette tape using a video camera and a time-lapse video recorder. The change in the fringe patterns is analysed using the image-processing system. Tidal deformations obtained from the holographic method are consistent with the strain changes observed with laser extensometers in the same tunnel. These observational results substantiate the tunnel deformation estimated by finite-element calculations.