661 research outputs found
Digitized Astronomical Photographic Archives as Large Area Sky Survey of Large Amount of Astronomical Data
We report here on an investigation of astronomical plate archives and tests of the scanning devices for digitization of archival astronomical plates. These archives represent huge database of
historical astronomical data, astrometric, photometric, and spectroscopic, with many applications in modern astrophysics
Fish eye optics
We report on small student (high school) project of the Czech Academy of Sciences dealing with animal (fish) eyes and possible application in science and technology. Albeit most fishes have refractive eyes, the recent discoveries confirm that some fishes have reflective eyes with strange arrangements as well
A novel method for identifying Fast Optical Transients on astronomical archival plates
We report on a novel method to identify brief optical transients (OTs) on astronomical archival photographic plates. This method does not require identification of all objects and their comparison with the catalogue, but rely solely on the information included in the particular plate itself
Ultra Low Dispersion Spectroscopy with Gaia and Astronomical Slitless Surveys
The ultra-low dispersion spectroscopy to be applied in the ESA Gaia space observatory and the ground-based objective-prism plate surveys represent a similar type of astrophysical data. Although the dispersion in plate surveys is usually larger than in the Gaia blue and red photometers (BP/RP), the spectral resolutions differ by a factor of 2–3 only, since the resolution in ground-based spectra is seeing-limited. We argue that some of the algorithms developed for digitized objective-prism plates can also be applied for the Gaia spectra. At the same time, the plate results confirm the feasibility of observing strong emission lines with Gaia RP/BP
Mixed Noise Suppression in Color Images by Signal-Dependent LMS L-Filters
The paper is devoted to the signal-dependent (SD) design of adaptive LMS L-filters with marginal data ordering for color images. The same stem of SD processing of noised grayscale images was applied on noisy color images. Component-wise and multichannel modifications of SD LMS L-filter in R'G'B' (gamma corrected RGB signals) color space were developed. Both modifications for filtering two-dimensional static color images degraded by mixed noise consisting of additive Gaussian white noise and impulsive noise were used. Moreover, single-channel spatial impulse detectors as detectors of impulses and details were used, too. Considering experimental results, SD modifications of L-filters for noisy color images can be concluded to yield the best results
Ultra Low-Dispersion Spectroscopy with Gaia and Photographic Objective Prism Surveys
This paper discusses the ultra low-dispersion spectroscopy to be applied in the ESA Gaia space observatory and the ground-based objective-prism plate surveys. Although the dispersion in plate surveys is usually larger than in the Gaia BP/RP spectrometers, the spectral resolutions differ by a factor of 2–3 only, since the resolution in ground-based spectra is seeing-limited. We argue that some of the algorithms developed for digitized objective-prism plates can also be applied for the Gaia spectra. At the same time, the plate results confirm the feasibility of observing strong emission lines with Gaia RP/BP
Golden Era of Cataclysmic Variables and Related Objects II: Concluding Remarks
The cataclysmic variables continue to represent important part of modern astrophysics, as demonstrated, already second time, by the productive and successful conference Golden Era of Cataclysmic Variables and Related Objects II held on Mondello (Palermo) in September 2013
The Puzzle of V407 Cygni
We discuss the nature and recent observations (optical and gamma-rays) of symbiotics binary/Mira variable V407 Cygni. In addition we discuss another object of similar category, namely the variable star FY Aql with possible association with an eruptive gamma-ray source
Extension of Impulse Detectors to Spatial Dimension and their Utilization as Switch in the LMS L-SD Filter
In this paper, one kind of adaptive LMS filters based on order statistics is used for two-dimensional filtration of noisy greyscale images degraded by mixed noise. The signal-dependent adaptive LMS L-filter (L-SD) consists of two normalized constrained adaptive LMS L-filters, because they have better convergence properties than simple LMS algorithm. Moreover, first filter suppresses the noise in homogeneous regions and second filter preserves the high components of filtered image. Some versions of spatial order statistic detectors were developed from the impulse detectors and were employed as switch between output these filters
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