scholarly journals Photoelectric Polarimetry of the Tail of Comet Ikey-Seki (1965 VIII)

1976 ◽  
Vol 25 (Part1) ◽  
pp. 92-120 ◽  
Author(s):  
J. L. Weinberg ◽  
D. E. Beeson
Keyword(s):  
High Spatial Resolution ◽  
Small Region ◽  
Field Of View ◽  
Large Field ◽  
Small Range ◽  
Comet Tail ◽  
Small Aperture ◽  
Spatial Coverage ◽  
Phase Angles ◽  
Small Field Of View

With few exceptions, measurements of cometary brightness and polarization have been restricted to regions in or near the coma and therefore to a relatively small range of phase angles. Photoelectric techniques are required for detailed wavelength coverage, whereas large-field photographic techniques are better suited for mapping the large regions of sky spanned by a comet tail. Observations with a small field of view provide high spatial resolution but generally restrict multicolor measurements of brightness and polarization to a small region of the comet. Observations with a large field of view (diameter larger than 1 or 2 deg) provide adequate color and spatial coverage but can result in the loss of detail. A compromise is afforded by Fabry photometry, using a modest telescope of small aperture and relatively large field of view.

scholarly journals Shadow monochromatic backlighting: Large-field high resolution X-ray shadowgraphy with improved spectral tunability

2001 ◽  
Vol 19 (2) ◽  
pp. 285-293 ◽  
Author(s):  
T.A. PIKUZ ◽  
A. YA. FAENOV ◽  
M. FRAENKEL ◽  
A. ZIGLER ◽  
F. FLORA ◽  
...  
Keyword(s):  
High Resolution ◽  
High Spatial Resolution ◽  
Field Of View ◽  
Large Field ◽  
X Ray ◽  
Traditional Scheme ◽  
Wide Range ◽  
Wide Wavelength Range ◽  
Bent Crystals ◽  
First Time

The shadow monochromatic backlighting (SMB) scheme, a modification of the well-known soft X-ray monochromatic backlighting scheme, is proposed. It is based on a spherical crystal as the dispersive element and extends the traditional scheme by allowing one to work with a wide range of Bragg angles and thus in a wide spectral range. The advantages of the new scheme are demonstrated experimentally and supported numerically by ray-tracing simulations. In the experiments, the X-ray backlighter source is a laser-produced plasma, created by the interaction of an ultrashort pulse, Ti:Sapphire laser (120 fs, 3–5 mJ, 1016 W/cm2 on target) or a short wavelength XeCl laser (10 ns, 1–2 J, 1013 W/cm2 on target) with various solid targets (Dy, Ni + Cr, BaF2). In both experiments, the X-ray sources are well localized spatially (∼20 μm) and are spectrally tunable in a relatively wide wavelength range (λ = 8–15 Å). High quality monochromatic (δλ/λ ∼ 10−5–10−3) images with high spatial resolution (up to ∼4 μm) over a large field of view (a few square millimeters) were obtained. Utilization of spherically bent crystals to obtain high-resolution, large field, monochromatic images in a wide range of Bragg angles (35° < Θ < 90°) is demonstrated for the first time.

scholarly journals The Use of the Hubble Space Telescope for Global Reference Frame Work

1986 ◽  
Vol 7 ◽  
pp. 87-88
Author(s):  
P. D. Hemenway
Keyword(s):  
Transfer Functions ◽  
Hubble Space Telescope ◽  
Field Of View ◽  
Optimum Conditions ◽  
Small Aperture ◽  
Space Telescope ◽  
Frame Work ◽  
Global Reference Frame ◽  
Better Than ◽  
Small Field Of View

The Hubble Space Telescope (HST) will have the capability of making relative astrometric measurements with an accuracy of four to ten times better than similar ground based measurements. The instruments of choice will be the Fine Guidance Sensors (FGS’s). Details of the instrumentation have been given elsewhere (c.f. Jefferys, 1980). Each FGS consists of two interferometer detectors which look at a small aperture located within a larger field of view (FOV). The raw data consist of encoder readings, from “star selectors”, and error signals derived from the interferometer transfer functions. The star selector positions determine the position of the small aperture within the pickles. The precision is always less than 0.001 arcsec, with an expected accuracy of 0.002 to 0.003 arcsec per observation. Under optimum conditions, the best expected accuracy is 0.0016 arcsec per observation. An observation will consist of the relative positions of several objects in one pickle. Thus the highest accuracy observations will be relative observations within a relatively small field of view.

scholarly journals The Instrument Design of Lightweight and Large Field of View High-Resolution Hyperspectral Camera

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2276
Author(s):  
Xinghao Fan ◽  
Chunyu Liu ◽  
Shuai Liu ◽  
Yunqiang Xie ◽  
Liangliang Zheng ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Spectral Resolution ◽  
High Spatial Resolution ◽  
Instrument Design ◽  
Field Of View ◽  
Large Field ◽  
Challenging Problem ◽  
Ground Sample ◽  
The Cost ◽  
Hyperspectral Camera

The design of compact hyperspectral cameras with high ground resolution and large field of view (FOV) is a challenging problem in the field of remote sensing. In this paper, the time-delayed integration (TDI) of the digital domain is applied to solve the issue of insufficient light energy brought by high spatial resolution, and a hyperspectral camera with linear variable filters suitable for digital domain TDI technology is further designed. The camera has a wavelength range of 450–950 nm, with an average spectral resolution of 10.2 nm. The paper also analyzed the effects of digital domain TDI on the signal–noise ratio (SNR) and the spectral resolution. During its working in orbits, we have obtained high-SNR images with a swath width of 150 km, and a ground sample distance (GSD) of 10 m @ 500 km. The design of the hyperspectral camera has an improved spatial resolution while reducing the cost.

scholarly journals Detection of cerebral tauopathy in P301L mice using high-resolution large-field multifocal illumination fluorescence microscopy

2020 ◽  
Author(s):  
Ruiqing Ni ◽  
Zhenyue Chen ◽  
Juan A. Gerez ◽  
Gloria Shi ◽  
Quanyu Zhou ◽  
...  
Keyword(s):  
High Resolution ◽  
Fluorescence Microscopy ◽  
Field Of View ◽  
Large Field ◽  
Depth Of Focus ◽  
Microscopy Technique ◽  
Microscopy Techniques ◽  
Small Field Of View

AbstractCurrent intravital microscopy techniques visualize tauopathy with high-resolution, but have a small field-of-view and depth-of-focus. Herein, we report a transcranial detection of tauopathy over the entire cortex of P301L tauopathy mice using large-field multifocal illumination (LMI) fluorescence microscopy technique and luminescent conjugated oligothiophenes. In vitro assays revealed that fluorescent ligand h-FTAA is optimal for in vivo tau imaging, which was confirmed by observing elevated probe retention in the cortex of P301L mice compared to non-transgenic littermates. Immunohistochemical staining further verified the specificity of h-FTAA to detect tauopathy in P301L mice. The new imaging platform can be leveraged in pre-clinical mechanistic studies of tau spreading and clearance as well as longitudinal monitoring of tau targeting therapeutics.

scholarly journals Achieving high spatial resolution in a large field-of-view using lensless x-ray imaging

2021 ◽  
Vol 119 (12) ◽  
pp. 124101
Author(s):  
Yi Jiang ◽  
Junjing Deng ◽  
Yudong Yao ◽  
Jeffrey A. Klug ◽  
Sheikh Mashrafi ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Field Of View ◽  
Large Field ◽  
X Ray ◽  
X Ray Imaging
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