On-orbit calibration of space camera based on stellar image correspondences

2015 ◽  
Author(s):  
You Zhai ◽  
Luan Zeng ◽  
Wei Xiong
Keyword(s):  
Stellar Image

scholarly journals Active alignment of space astronomical telescopes by matching arbitrary multi-field stellar image features

2021 ◽  
Author(s):  
Guohao JU ◽  
Hongcai Ma ◽  
Boqian Xu ◽  
Shuaihui Wang ◽  
chunyue zhang ◽  
...  
Keyword(s):  
Image Features ◽  
Stellar Image

Stellar Image Denoising Method for Active Pixel Sensor Based on Dynamic Sequential Noise Template

2019 ◽  
Vol 39 (3) ◽  
pp. 0315006
Author(s):  
谢俊峰 Xie Junfeng ◽  
朱红 Zhu Hong ◽  
李品 Li Pin ◽  
莫凡 Mo Fan ◽  
李响 Li Xiang
Keyword(s):  
Image Denoising ◽  
Denoising Method ◽  
Active Pixel Sensor ◽  
Active Pixel ◽  
Stellar Image

The Solid State Area Scanner Photometer

1983 ◽  
Vol 62 ◽  
pp. 220-223
Author(s):  
Karl D. Rakos
Keyword(s):  
Solid State ◽  
Reduction Method ◽  
Tracking Error ◽  
Optical Quality ◽  
Integration Time ◽  
Spectral Dispersion ◽  
Periodic Error ◽  
State Area ◽  
Stellar Image

The accuracy of the area scanning technique depends on observing conditions resulting from seeing, tracking irregularities of the telescope, photon and seeing statistics (integration time and the size of the telescope), and the atmospheric spectral dispersion of the stellar image in the spectral region used. In addition, the reduction method as well as the mechanical and optical quality of the telescope and photometer influence the accuracy of the results.The tracking error of the telescope is usually larger than the observer believes. The amplitude of the periodic error of the worm gear is at best ± 0.5 arc sec with period length between 4 and 10 minutes, depending on the particular telescope. Figure 1 shows the tracking error for the ESO 50 cm and 100 cm telescopes. Other telescopes usually fit in between this two extremes.

scholarly journals Stellar Image Location with Maximum Correlation Procedure

1995 ◽  
Vol 166 ◽  
pp. 363-363
Author(s):  
Zhu Zi
Keyword(s):  
Observational Data ◽  
Estimation Method ◽  
Positional Accuracy ◽  
Maximum Correlation ◽  
Single Star ◽  
Mathematical Performance ◽  
Location Methods ◽  
Photoelectric Technique ◽  
Correlation Procedure ◽  
Stellar Image

The location method and accuracy analysis has become a very important subject in astrometry since the photoelectric technique was widely applied. The location methods of the stellar images observed with the slit micrometer are discussed in this paper, and a new estimation method called the maximum correlation procedure is presented. This procedure has already been used to process and analyze the observational data. Because of the ideal mathematical performance of the correlation function, the procedure provides us a good way to determine image locations. By means of simulated observations according to the theoretical analysis, we find that the locating accuracy and the limiting magnitude for this method is much higher than those of traditional locating method. For the observational data of about one thousand stars obtained with the Photoelectric Astrolabe at Yunnan Astronomical Observatory, the positional accuracy of a single star using the maximum correlation is improved by 0.045 arcsec over that with the median. The maximum correlation procedure has also increased the data reduction ability for faint star observations with very low signal to noise ratios.

scholarly journals The Compared Efficiency Of Centering Algorithms

1988 ◽  
Vol 133 ◽  
pp. 389-392
Author(s):  
O. Bienaymé ◽  
C. Motch ◽  
M. Crézé ◽  
S. Considère
Keyword(s):  
Digital Image ◽  
Reliable Method ◽  
Fast Algorithms ◽  
Marginal Distributions ◽  
Stellar Image

SummaryThe purpose of this study is to compare the quality of three digital image centering algorithms; 1) the fit of marginal distributions by Gaussian, 2) the maximum of the Autocorrelation of a stellar image by its symmetrical, 3) the 2–dimensional fit of stellar images by a mean stellar Profile.The two main conclusions are: 1) the 3 centering methods give the same accuracy if the star is isolated, bright and unsaturated. But as soon as one of these conditions fails, fast algorithms lack robustness and the only reliable method is the 2-d profile fit, 2) preliminary tests on Schmidt plates digitized with the MAMA (Machine Automatique à Mesurer pour l'Astronomie) show that under the above restrictions, the centering algorithms do not alter the final astrometric accuracy, neither do the digitizing machine.

scholarly journals Six years of astrometric monitoring of the OH maser in U Herculis

2002 ◽  
Vol 206 ◽  
pp. 327-330
Author(s):  
Wouter Vlemmings ◽  
Huib Jan van Langevelde ◽  
Phil Diamond
Keyword(s):  
Proper Motion ◽  
Bright Spot ◽  
Maser Spot ◽  
Stellar Image

Using VLBI phase referencing, we have been registering the position of the most blue-shifted OH 1667 MHz maser spot with respect to nearby extragalactic reference sources for almost seven years. The data for these 10 epochs allow us to determine the proper motion and parallax of U Her. It also yields the opportunity to compare the maser position to the position of the star, as measured by the Hipparcos satellite. Results support the theory that the compact bright spot is the amplified stellar image.

scholarly journals The precision calcium photometer: A New Instrument for Astroseismology

1988 ◽  
Vol 123 ◽  
pp. 521-524
Author(s):  
P. Nisenson ◽  
A. K. Dupree ◽  
R. W. Noyes
Keyword(s):  
Optical Fiber ◽  
Optical System ◽  
Photon Counting ◽  
Image Stabilization ◽  
New Instrument ◽  
Counting Mode ◽  
Photon Counting Mode ◽  
System Characteristics ◽  
Stellar Image

The Precision CAlcium Photometer (PCAP) has been built with characteristics optimized for amplitude astroseismology. The instrument consists of two units: an on-telescope optical system that forms and stabilizes a stellar image onto a 200 micron optical fiber; and a spectrometer unit that accepts the light from the fiber and integrates the Calcium II H and K lines (3968.5 Å and 3933.7 Å), along with adjacent continuum regions, in a photon-counting mode. Some key system characteristics include active image stabilization, a 12-meter optical fiber with ~70% transmission at 3950 Å, and a thermally and mechanically stable spectrometer. A description of the instrument and of laboratory and on-telescope test runs are discussed below.

scholarly journals Astrometry of the stellar image of U Her amplified by the circumstellar 22 GHz water masers

2002 ◽  
Vol 393 (2) ◽  
pp. L33-L36 ◽  
Author(s):  
W. H. T. Vlemmings ◽  
H. J. van Langevelde ◽  
P. J. Diamond
Keyword(s):  
Water Masers ◽  
Stellar Image

RC telescope alignment based on out-of-focus stellar image

2011 ◽  
Vol 19 (4) ◽  
pp. 728-736
Author(s):  
孙敬伟 SUN Jing-wei ◽  
陈涛 CHEN Tao ◽  
王建立 WANG Jian-li ◽  
张金凯 ZHANG Jin-kai
Keyword(s):  
Stellar Image
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