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November 16, 2000

    XML and the PIXY System 2    

MISAO Project Announce Mail (November 16, 2000)

Hello. I am Seiichi Yoshida working on the MISAO project.

The new version of the PIXY System 2, the next generation of the Practical Image eXamination and Inner-objects Identification system, is released on Nov. 12, 2000. This is the 7th version up release since the first release on June 24.

There are two main use cases of the current PIXY System 2.

  1. Examine one image comparing to a catalog.
  2. Compare two images.

In the first case, star catalogs such as GSC 1.1, USNO-A2.0, etc., are required. The R.A. and Decl., and the magnitude of all stars in the image are automatically measured. Stars not recorded in the catalog are picked up. You can list up all comets, asteroids, variable stars, clusters and nebulae in the image. You can also make a magnitude report for VSNET of many variable stars in the image automatically.

In the second case, two images of the same area are compared each other. Comets, asteroids and variable stars are marked up colorfully. You can also blink the images.

The tutorial pages which introduce the usage of the PIXY System 2 for both cases using sample images are available at the home page of the system.

  • Examine your image
  • Look up comets, asteroids, variable stars, clusters and nebulae in the image field
  • Magnitude report of variable stars to VSNET
  • How to discover comet or asteroid
  • How to discover variable star

The result of the image examination in the first case can be saved in the XML file. Open the XML file and the desktop of the image examination is reproduced again, then you can review the result or continue analysis such as identification of comets, asteroids, variable stars, clusters and nebulae in the image.

In the tutorial pages of the PIXY System 2, the XML files of the sample images are available in addition to the images themselves. You can experience the PIXY System 2 immediately opening the XML files.

The XML (eXtensible Markup Language) is a form to save a document or data in a file. It is one of the most remarkable techniques now. The data is formatted by tags and the document structure is described in the DTD (Document Type Definition). The common framework of the tagged file and the DTD brings some merits. It makes data exchange easy. The program to read or write the XML file can be held in common. Shiro Nishimura introduce me that the NASA Astronomical Data Center promotes the conversion of catalogs into XML.


The PIXY System 2 adopts the RELAX and Relaxer techniques, too. The RELAX enables to define data structure much more in details than DTD. The Relaxer automatically generates specific programs to parse the XML file based on the RELAX definition. The PIXY System 2 utilizes the generated programs.

The details of the XML and the PIXY System 2 are available in the special page on the XML.


As the old PIXY System did, the examination result can be also saved in PXF file. The system cannot read PXF file and cannot reproduce the desktop from the PXF file. However, the format of the PXF file is easy to be read by script programs like Perl.

Using the latest version of the PIXY System 2, you can identify comets and asteroids using the Minor Planet Checker, variable stars based on the GCVS 2000 edited by Taichi Kato and Makoto Iida, and clusters and nebulae based on the NGC 2000.0. The identification result can be viewed in the overview chart and report table. You can plot any of the identified stars on the chart, and read the data by mouse. You can verify the identification of each star in the table, based on the distance between the identified stars and detected star images, referring to the data of all stars.

By the way, John Greaves, Jim McCullough, Taichi Kato, Klaus Bernhard, and many people send me e-mails with information of various catalogs. They will be supported in the next or the later version. So will be the many other catalogs supported by the old PIXY System.

The past MISAO project announce mails are available at:


Seiichi Yoshida

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