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[en] A novel charge-coupled device concept and structure (the overlaid CCD) is described. The device operates by transferring charge packets on two distinct levels which are overlaid in the semiconductor bulk. This bulk-integrated CCD has an increased density per unit area and a reduced driving power consumption per bit, compared to conventional buried-channel CCD's, still enjoying bulk-channel operation. Furthermore, the overlaid CCD can be employed to perform certain operations that could otherwise be performed only at greater expense. The price to be paid is a smaller charge-carrying capacity of the deeper-laying transfer level. The operational characteristics of the new device are investigated by means of analytic as well as two-dimensional numerical calculations. (author)
[en] A novel method for small angular displacement measurement based on an autocollimator and a common-path compensation principle by using single CCD detector was proposed. The principles of the angular displacement measurement and the common-path compensation were analyzed. The feasibility of measurement method was verified and the experimental results revealed that the linear correlativity between the relative displacement of the measuring beam spot and the angular displacement is 0.99996. And the measurement resolution is about 0.03 arcsec. To test the compensation's effect, a series of experiments introducing three different interferences from system and external environment were performed. The experimental results indicated that the standard deviations of the measuring beam spot's angular drift were improved by at least 25.0% to at most 80.0% in x direction while by at least 28.2% to at most 95.6% in y direction. Thus, the stability of the system and the measurement resolution were improved.
[en] From a study of two methods for the use of CCDs as photometers, it is shown that high-precision relative photometry of variable stars is possible using a CCD detector under nonphotometric conditions with good time resolution and a fainter magnitude limit than is possible with photomultipliers. The method consisting of trailing a group of stellar images along columns of the CCD at a rate of several seconds of time per pixel is useful for brighter objects, and the time resolution can be substantially shorter than one second. The method involving the taking of repeated short exposures of a particular star field containing the star of interest can be used on faint stars of V greater than 15 provided that the required time resolution is not less than about 15 seconds. Stars as faint as V of 18.5 were observed with time resolutions of three minutes and photometric accuracy of better than 0.04 magnitude using the repeated exposure method. 8 references
[en] We discuss a number of physical effects about deeply depleted CCDs that have a significant impact on shape estimation. In particular, the focus is on issues related to measuring accurate shear values of galaxies for weak lensing science. There are three types of effects we discuss: effects related to the world coordinate system (WCS), the so-called brighter-fatter relation, and variable pixel size. In each case, we describe the effect, explain the impact on shape measurements, and propose possible solutions
[en] By scanning a charge-coupled device (CCD) camera transverse to the beam axis and observing the variation in counts on a marked pixel, we demonstrate that we can measure a laser beam spot size smaller than the size of the CCD-pixel. We find this method particularly attractive for measuring the size of central spot of a Bessel beam, for which the established scanning knife-edge method does not work appropriately because of the large contribution of the rings surrounding the central spot to the signal
[en] The results of 2916 intensified CCD observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory, are presented. Each observation of a system represents a combination of over two thousand short-exposure images. These observations are averaged into 1584 mean relative positions and range in separation from 0.''54 to 98.''09, with a median separation of 11.''73. This is the 19th in this series of papers and covers the period 2012 January 5 through 2012 December 18. Also presented are 10 pairs that are reported for the first time, 17 pairs that appear to be lost, linear elements for 18 pairs, and orbital elements for 2 additional pairs
[en] In this paper, an approach for expanding the sampled area of a dynamic process by digital holography is reported, where angular, polarization and wavelength multiplexing are applied to record different regions of the sample on a series of sub-holograms overlapped in a single frame of the charge-coupled device. This approach based on a single exposure has special potential for the digital holographic recording of dynamic processes. (paper)
[en] Solid-state imaging devices (CCD, CID, Reticons) are finding increasing use as low-level light detectors in optical astronomy. Charged Coupled Devices are also used as memory storage elements in computers. In both applications the interaction of cosmic rays with the silicon is a serious limitation. Measurements of the event size distribution and event rate as a function of lead shielding with three CCD imaging cameras (Fairchild CCD 20 and RCA CCD ''thick'' and ''thin'' chips) are presented
[en] Extensive differential time-series CCD photometry has been carried out between 2003 and 2009 for the high-amplitude δ Scuti (HADS) star GP And. We acquired 12,583 new measurements consisting of 41 nights (153.3 hr) spanning over 2221 days. This is the largest time-series data set to date for the star. Based upon these data and others available in the literature, a comprehensive analysis has been conducted to investigate the pulsational properties of the star. Except for the known fundamental period and its harmonics we failed to detect any additional pulsation periods either radial or nonradial. We show clear amplitude variability, but we failed to verify the previously claimed periodic amplitude modulation. Classic O-C analysis indicates that the fundamental pulsation period of GP And is slowly increasing at a rate of P-dot /P = (5.49 ± 0.1)x10-8 yr-1 in accordance with the predictions of stellar evolutionary models. Findings of nonradial oscillations in previously known radial high-amplitude pulsators are being increasingly reported. We have briefly reviewed the current status of multiperiodicity and nonradial pulsation features among the high-amplitude pulsators in the classic instability strip.