Variable Stars Common Observation
Mission in Particular Areas of the Sky
Every VS-COMPAS team member has an internal access to a software package allowing to perform stellar variability period analysis. The software was created by Ivan Adamin and Andrey Prokopovich (Project Core Team). There are two versions exist currently: Windows desktop application and a web-based. The software allows to perform wide range of routine operations automatically. One of the most important automation feature - apart of period search itself - is an automatic photometry combining from different sources. This reduces the amount of time spent on that step significantly. Moreover, there are adjustable filters on top of photometric data, so an user could have a flexible control over the resulting plot.
Historically, a desktop version of the tool was initially implemented for basic processing of NSVS data series in order to detect star's variability. To determine the approximate values of the periods of new variable stars, the “WinEffect” software (Dr. Goransky, 2005) was used during the very first months of the project's life. The periods have been determined from the periodogram analysis using the Kholopov’s (1971) improvement of the method by Lafler and Kinman (1965). This software has influenced the overall trend for project development.
Soon there was a need in photometric surveys combining arisen. Further development lead to a more complex solution, including filtering data overlays and enhanced usability. Usability is what makes this software really effective. All the data a researcher needs for analysis is collected almost instantly from online public services (like VizieR and photometry archives) particularly for selected object. The program can process photometry from NSVS, ASAS and CRTS surveys, providing a way to discover a variable star and search for its periodicity much faster than it was before for the team.
The tool has rich set of options to manipulate data. There is no need in combining NSVS aliases photometry - it's all done automatically. For better portability, a significant part of data processing functionality was implemented as a web service. This allowed the same implementation to be used both for desktop and future web-based tool. Step by step, tool became more mature and complete. There was a feature allowing curve fitting added also.
Online Variability Period Explorer
Along with the desktop version, we have a prototype for online stellar variability research. This tool provides an "all-in-a-single-place" dashboard, allowing users transparently collect and analyze photometric data directly from a browser. No additional software have to be installed on a machine. All you need to provide to the service is object's coordinates or its ID within a survey (NSVS, CRTS, ASAS). Once this is provided, it loads all available data for the object automatically. Also, links to VizieR and Aladin services are created as well as star's designations, color indexes, etc.
As NSVS may have several aliased records for the same object, there is an automatic aliases merging feature available. It is extremely useful, since an user don't need to merge this data manually and get a resulting combined light curve points just instantly. Though the desktop version has more UI controls abilities due to application's nature, web version supports most of its functionality and is enough for a fast basic research online.
Online version can do period analysis within a period/frequency range, but there is a "Try Period" feature also, allowing users to verify if a particular period value is matching variability properties. You can get basic impression about the online version from the screen shot provided above.
Variables by Type
Variables by Magnitude
Variables by Period
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