scholarly journals Archives of Photometric Data

1992 ◽  
Vol 9 ◽  
pp. 725-726 ◽  
Author(s):  
J.-C. Mermilliod
Keyword(s):  
Data Retrieval ◽  
Photometric Data ◽  
Multiple Systems ◽  
Double Stars ◽  
Definition Of

The process of archiving photometric data and compiling catalogues is in principle easy to solve, but, in practice, does not appear so simple. Data retrieval may become difficult and inefficient if sufficient care is not taken to solve the general problems which are encoutered: (i) the lack of definition of fundamental identificators; (ii) the lack of coordinates for thousands of faint stars; (iii) the innacuracy of the identification and description of the components observed in double stars or multiple systems: A, B, C, AB, or BC; (iv) the fact that the number of observations is often not published.

scholarly journals Observational Programme for Classical and CCD Photometry of Visual Double and Multiple Systems

1992 ◽  
Vol 135 ◽  
pp. 339-342
Author(s):  
E. Oblak ◽  
P. Lampens
Keyword(s):  
Photometric Data ◽  
European Network ◽  
Ccd Photometry ◽  
Multiple Systems ◽  
Double Stars ◽  
Visual Double Stars ◽  
Astrometric Data ◽  
Input Catalogue ◽  
Colour Indices

Complementary accurate photometric data with astrophysical content are needed for a well-chosen sample of binaries and multiple systems for which good-quality astrometric data already exist or will soon be available. The observational programme, started in the context of the European Network of Laboratories “Visual Double Stars” (Oblak et al. 1992), is therefore based on samples extracted from the “Catalogue des Composantes d’Etoiles Doubles et Multiples” (CCDM, Dommanget, 1989) and reported in Annex 1 (Double and Multiple Systems) of the HIPPARCOS Input Catalogue (C. Turon et al. 1992).Systems with components in the HIPPARCOS Input Catalogue are selected for which the present photometric information is poor, i.e. not all components have been observed or they have colour indices and/or magnitudes of insufficient quality for extraction of astrophysical quantities (Figure 1).Observations, performed in various observatories located in both hemispheres, must yield both classical and CCD photometric campaigns.

scholarly journals Astrometric Standard Fields for CCD Observations of Double Stars

1994 ◽  
Vol 161 ◽  
pp. 291-293
Author(s):  
D. Sinachopoulos ◽  
E. Oblak ◽  
M. Geffert ◽  
J. Colin ◽  
J.-F. LeCampion ◽  
...  
Keyword(s):  
Scientific Community ◽  
Photometric Data ◽  
Stellar Systems ◽  
European Network ◽  
Multiple Star ◽  
Double Stars ◽  
Visual Double Stars ◽  
Ccd Observations ◽  
Formation And Evolution ◽  
Selection Of

The number of known double stars is steadily increasing, thanks to ground-based and space observations. Therefore the ratio of known double to single stars has to be revised upwards continuously. With the Hipparcos parallaxes it will be possible to get stellar statistics for precisely defined volumes of space. This will lead to strong constraints on all astrophysical calibrations of masses, spectral types and luminosities in the solar neighbourhood. A European network of laboratories was created in August 1990 in order to remedy the lack of photometric data for close visual double stars. This network intends to study all aspects of formation and evolution of double and multiple star systems. The immediate goal of the group is to provide the scientific community with a compilation of known photometric data on a large selection of close visual double stars and to significantly enlarge this information by new observations with modern devices. A photometric database of stellar systems is being compiled from most widely used photometric systems in collaboration with the ‘Centre de Données Stellaires’ of Strasbourg.

scholarly journals Etoiles Multiples Et Amas Ouverts

1977 ◽  
Vol 33 ◽  
pp. 67-72
Author(s):  
J. Dommanget
Keyword(s):  
Frequency Distribution ◽  
Basic Difference ◽  
Multiple Systems ◽  
Number Of Components ◽  
Double Stars ◽  
Dense Part ◽  
Galactic Clusters

AbstractIt is generally suspected that multiple systems and galactic clusters are objects of different kinds. Their frequency distribution as a function of the number of components, n, as well as their sizes and their masses, show important differences between both categories and also the probable existence of a limit lying between n = 10 and n = 20 components. The basic difference between these objects seems to be that the multiple systems finally appear to be components of the stellar medium in th same way as single and double stars, whereas the galactic clusters are groups of components of a particularly dense part of this medium.

Gaia Photometric Catalogue: the calibration of the DR2 photometry

2018 ◽  
Vol 14 (A30) ◽  
pp. 466-470
Author(s):  
D. W. Evans ◽  
M. Riello ◽  
F. De Angeli ◽  
J. M. Carrasco ◽  
P. Montegriffo ◽  
...  
Keyword(s):  
Scientific Community ◽  
Photometric Data ◽  
Photometric System ◽  
Gaia Dr1 ◽  
System A ◽  
Data Release ◽  
Definition Of ◽  
High Level ◽  
Crucial Part ◽  
Gaia Dr2

AbstractGaia DR2 was released in April 2018 and contains a photometric catalogue of more than 1 billion sources. This release contains colour information in the form of integrated BP and RP photometry in addition to the latest G-band photometry. The level of uncertainty can be as good as 2 mmag with some residual systematics at the 10 mmag level. The addition of colour information greatly enhances the value of the photometric data for the scientific community. A high level overview of the photometric processing, with a focus on the improvements with respect to Gaia DR1, was given. The definition of the Gaia photometric system, a crucial part of the calibration of the photometry, was also explained. Finally, some of the photometric improvements expected for the next data release were described.

scholarly journals CCD Photometry of Hipparcos Stellar Systems

1995 ◽  
Vol 166 ◽  
pp. 390-390
Author(s):  
E. Oblak ◽  
M. Chareton
Keyword(s):  
Photometric Data ◽  
Stellar Systems ◽  
Ccd Photometry ◽  
Double Stars ◽  
Visual Double Stars ◽  
Ccd Detectors

With the introduction of CCD detectors, it now appears feasible to obtain accurate photometric data for each of the components of close visual double stars with an angular separations between 1 and 12″.

A Fuzzy Ontology-Based Platform for Flexible Querying

2015 ◽  
Vol 6 (3) ◽  
pp. 12-26 ◽  
Author(s):  
Amira Aloui ◽  
Amel Grissa Touzi
Keyword(s):  
Fuzzy Logic ◽  
Initial Data ◽  
Data Retrieval ◽  
Conceptual Clustering ◽  
Large Databases ◽  
Flexible Queries ◽  
Definition Of ◽  
Preliminary Classification ◽  
Flexible Querying

Flexible queries have recently received increasing attention to better characterize the data retrieval. In this paper, a new flexible querying approach using ontological knowledge is proposed. This approach presents an FCA based methodology for building ontologies from scratch then interrogating them intelligently through the fusion of conceptual clustering, fuzzy logic, and FCA. The main contribution is the definition of the ontology rom classes resulting from a preliminary classification of the data and not the initial data. The data cleansing provides a simple ontology and an optimal research of relevant data taking into account the preferences cited by the user in his initial interrogation. To realize this approach, a new platform called “FO-FQ Tab plug-in” is implemented. This plug-in is integrated within the ontology editor Protégé to allow building fuzzy ontologies from large databases and querying them intelligently

Providing a user-friendly outlier analysis service implemented as open REST API

2020 ◽  
Author(s):  
Doron Goldfarb ◽  
Johannes Kobler ◽  
Johannes Peterseil
Keyword(s):  
Web Service ◽  
Data Retrieval ◽  
Environmental Data ◽  
Data Repository ◽  
Outlier Analysis ◽  
Data Set ◽  
Access Methods ◽  
Rest Api ◽  
Definition Of ◽  
User Friendly

<p>As outliers in any data set may have detrimental effects on further scientific analysis, the measurement of any environmental parameter and the detection of outliers within these data are closely linked. However, outlier analysis is complicated, as the definition of an outlier is controversially discussed and thus - until now - vague. Nonetheless, multiple methods have been implemented to detect outliers in data sets. The application of these methods often requires some statistical know-how.</p><p>The present use case, developed as proof-of-concept implementation within the EOSC-Hub project, is dedicated to providing a user-friendly outlier analysis web-service via an open REST API processing environmental data either provided via Sensor Observation Service (SOS) or stored as data files in a cloud-based data repository. It is driven by an R-script performing the different operation steps consisting of data retrieval,  outlier analysis and final data export. To cope with the vague definition of an outlier, the outlier analysis step applies numerous statistical methods implemented in various R-packages.</p><p>The web-service encapsulates the R-script behind a REST API which is decribed by a dedicated OpenAPI specification defining two distinct access methods (i.e. SOS- and file-based) and the required parameters to run the R-script. This formal specification is subsequently used to automatically generate a server stub based on the Python FLASK framework which is customized to execute the R-script on the server whenever an appropriate web request arrives. The output is currently collected in a ZIP file which is returned after each successful web request. The service prototype is designed to be operated using generic resources provided by the European Open Science Cloud (EOSC) and the European Grid Initiative (EGI) in order to ensure sustainability and scalability.</p><p>Due to its user-friendliness and open availability, the presented web-service will facilitate access to standardized and scientifically-based outlier analysis methods not only for individual scientists but also for networks and research infrastructures like eLTER. It will thus contribute to the standardization of quality control procedures for data provision in distributed networks of data providers.</p><p> </p><p>Keywords: quality assessment, outlier detection, web service, REST-API, eLTER, EOSC, EGI, EOSC-Hub</p>

scholarly journals The Catalogue of the Components of Double and Multiple Stars (CCDM) - First Edition

1995 ◽  
Vol 166 ◽  
pp. 395-395 ◽  
Author(s):  
J. Dommanget ◽  
O. Nys
Keyword(s):  
Data Base ◽  
Multiple Star ◽  
Multiple Systems ◽  
Double Stars ◽  
Multiple Stars ◽  
Double And Multiple Stars ◽  
General Data ◽  
Input Catalogue ◽  
Better Than

The Hipparcos mission required the realisation of an Input Catalogue giving the positions of 100.000 stars (single or components of double and multiple systems) to an accuracy better than 1″5. At the start of this work (1981) no specific catalogue of double and multiple stars provided these data. The only general data base on double stars available to us, giving positions to ±1′, was the Index (1961,0) updated at the USNO by C. E. Worley till 1976,5 and of which a copy was communicated by P. Muller of the Observatoire de Meudon. It has then been decided to reformat this Catalogue in such a way as to allow the introduction of all necessary information for the mission. This permitted a correct cross-identification with the Hipparcos Input Catalogue (of finally 118.000 stars). It was later called: the Catalogue of the Components of Double and Multiple stars (CCDM). Since then, it has been developed and its aim remains to furnish the best accurate locations and descriptions of the double and multiple systems on the sky for all double and multiple star research.

A new genus and species of the family Isididae (Coelenterata: Octocorallia) from a CMAR Biodiversity study, and a discussion on the subfamilial placement of some nominal isidid genera

Zootaxa ◽  
2012 ◽  
Vol 3154 (1) ◽  
pp. 21 ◽  
Author(s):  
PHILIP ALDERSLADE ◽  
CATHERINE S. MCFADDEN
Keyword(s):  
Internal Structure ◽  
New Genus ◽  
New Genus And Species ◽  
Double Stars ◽  
The Family ◽  
Biodiversity Study ◽  
Definition Of

We describe a new abyssal genus and species of bamboo coral (family Isididae) with some markedly unusual characteris-tics, collected from a depth of just over 2000 m off southern Tasmania. Jasonisis thresheri n. gen., n. sp. possesses a fleshytegument that contains nematocysts, tubular axial internodes that are internally partitioned, scale-shaped sclerites thathave a morphology not recorded before for octocorals, and polyps that lack thorny rods or double stars in the pharynx.Molecular data place Jasonisis n. gen. in the subfamily Keratoisidinae whose definition is altered to incorporate the un-usual characters. We also report some comparative observations on the internal structure of the axial internodes of theisidid genera Keratoisis Wright, 1869, Lepidisis Verrill, 1883 and Isidella Gray, 1857, and we alter the definition of thesubfamily Mopseinae to allow the inclusion of the genera Tenuisis, Echinisis sensu Bayer & Stefani 1987 and Sclerisis sensu Bayer & Stefani 1987.

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