Cartes du Ciel is free software released under the terms of the
GNU General Public License
SAMP is a messaging protocol, part of the Virtual Observatory, that enables astronomy software tools to interoperate and communicate. Skychart can connect to this other tools and send or receive coordinates position, FITS images and VO tables or selections.
Very useful tools to use with Skychart are Topcat and Aladin.
To start to use SAMP with Skychart you can configure some options from the menu Setup -> General -> SAMP. This include how to connect to the hub, which function request to accept, and how to keep the data after the program is closed.
If you select to not connect automatically, or if the hub is not running when you start Skychart, you need to connect from the menu File -> SAMP.
For all this function you have the choice to broadcast the message to every client or to select a single destination client from a list.
To send coordinates use the right click menu SAMP send coordinates.
You can send a VO table data you get in Skychart from the VO catalog setup. Only VOtable format is supported.
When you left click on the chart on an object that is part of a shared VO table the selected object is send as a selection. This is limited to single row selection.
To send a FITS image use the chart right click menu Image list, the “Send image” button.
Remember you can configure which message you want to receive and if you want a confirmation message before to take the action.
Also configure how you want to retain the data when the program is closed. This allow to make a complex data selection using Topcat for example and take the data offline for use with Skychart at the telescope.
Center the chart on the received coordinates and search for an object at this location.
If an object is found you can use all the function available in this case: show detailed information, slew the telescope, …
Add the table to the VO catalog list and display the objects on the chart. Only VOtable format is supported.
You can change the symbol, the color or the column selection with the Update button below the list.
Mark the selected objects in green on the chart.
Display the image and center the chart the same way as with a DSS image download. Only FITS format is supported.
We want to display on the chart the super-giant stars in the Hyades area using the XHIP catalog as the source of data. If you already know how to work with Topcat you can skip to the last three steps.
On Skychart make a chart centered on the Hyades with a FOV of 20°.
On Topcat click the menu VO → Vizier catalog service. Object name: hyades, click Resolve, enter 10 for the radius (degrees).
For “Output columns” select “all”.
For Catalog selection, click “By keyword”, for “Keyword” enter XHIP, click Search catalogues, select “V/137D” on the list. Click OK.
After you get this basic example working you can explore all the powerful function that Topcat can offer to produce the ideal catalog for the data you need. Start by the other options in the VO menu and also try the Joins menu to merge the data from many original tables.