Among the functions the Cluster Database supplies the tclets are usefull tool for various researches (for example, for identification of radio and of optical sources).

These tclets work with wish interpreter on user side. They are generated on the fly by CGI module when requested.
The tclet displays the field of the sky where the inquired Cluster of galaxies from Abell catalog is located. Well, the scheme of field is displayed.

Two windows are created: Control window contains some buttons and Field window contains a picture. Three type of object are present on the picture:

- the galaxies from APM optical data (blue colored objects),
- the radio sources from FIRST catalogue (brown colored objects) and
- the radio sources from NVSS catalogue (green objects).

The galaxies are shown as ovals with axis taken from APM. The radio sources are shown as crosses.
When mouse is over the object this object put into other color (more dark as a rule) and the info is displyed at bottom of the Field window: the coordinates of object, the size (a and b axis), the positional angle of a-axis, star magnitude (for galaxy) or flux density at frequency 1400 MHz.

The tclet supplies some useful actions.

The picture usually contains several hundreds of objects. So some objects lay over another one.
To place the current object under all other click on left mouse button.
To remove the object click on right one.
To scale the picture with some scale factor click on middle mouse button (3-button mouse desirable).
To restore scale click the middle button once more.

You can switch off/on all objects of some type by clicking on the Control window buttons: "Galaxies", "FIRST radio objects" or "NVSS radio objects".
If you had some objects removed you can restore them by clicking the "Objects restore" button.

You can change scale factor by clicking on appropriate button with number "2", "3" or "10".

You can create a list of objects you are interested in by clicking left button while Shift key's pressed when mouse pointer is over the object. Then the info about this object appears in the table in bottom of Field window. Some extra function are defined for objects of the list. When pointer is over info string the corresponding object put in the other color (just if the pointer is over this object). On the contrary when pointer is over the object the corresponding string of the list put into another color.
You can remove the info string clicking the right mouse button.

These tclets are used to solve some real astronomical problems such as the identifying of radio sources. In a while we intend to add extra features to our tclets.

Good luck in your work!

Detailed information may be asked by E-mail:

tit@astro.spbu.ru
or
ag@astro.spbu.ru

        1 March 1999