SAMP integration

As of commit 4d0d133, or version 2.0.0, Gaia Sky supports interoperability via SAMP. However, due to the nature of Gaia Sky, not all functions are yet implemented and not all types of data tables are supported.

Since Gaia Sky only displays 3D positional information there are a few restrictions as to how the integration with SAMP is implemneted.

The current implementation only allows using Gaia Sky as a SAMP client. This means that when Gaia Sky is started, it automatically looks for a preexisting SAMP hub. If it is found, then a connection is attempted. If it is not found, then Gaia Sky will attempt further connections at regular intervals of 10 seconds. Gaia Sky will never run its own SAMP hub, so the user always needs a SAMP-hub application (Topcat, Aladin, etc.) to use the interoperability that SAMP offers.

Also, the only supported format in SAMP is VOTable through the STIL data provider described below.

STIL data provider

Gaia Sky supports the loading of data in VOTable, CSV, ASCII, etc. using the STIL library. It tries to make educated guesses using UCDs and column names to attribute semantics to columns. Here is what this provider can work with:

Positions

For the positional data, Gaia Sky will look for spherical and cartesian coordinates. In the case of spherical coordinates, the following are supported:

  • Equatorial (pos.eq.ra, pos.eq.dec)
  • Galactic (pos.galactic.lon, pos.galactic.lat)
  • Ecliptic (pos.ecliptic.lon, pos.ecliptic.lat)

To work out the distance, it looks for pos.parallax and pos.distance. If either of those are found, they are used. Otherwise, a default parallax of 0.04 mas is used. With respect to cartesian coordinates, it recognizes pos.cartesian.x|y|z, and they are interpreted in the equatorial system by default. If no UCDs are available, only equatorial coordinates (ra, dec) are supported, and they are looked up using the column names.

Proper motions

Proper motions are not yet supported via SAMP.

Magnitudes

Magnitudes are supported using the phot.mag or phot.mag;stat.mean UCDs. Otherwise, they are discovered using the column names mag, bmag, gmag, phot_g_mean_mag. If no magnitudes are found, the default value of 15 is used.

Colors

Colors are discovered using the phot.color UCD. If not present, the column names b_v, v_i, bp_rp, bp_g and g_rp are used, if present. If no color is discovered at all, the default value of 0.656 is used.

Others

Other physical quantities (mass, flux, T_eff, radius, etc.) are not yet supported via SAMP.

Implemented features

The following SAMP features are implemented:

  • Load VOTable (table.load.votable) - The VOTable will be loaded into Gaia Sky if it adheres to the format above.
  • Highlight row (table.highlight.row) - The row (object) is set as the new focus if the table it comes frome is already loaded. Otherwise, Gaia Sky will not load the table lazily.
  • Broadcast selection (table.highlight.row) - When a star of a table loaded via SAMP is selected, Gaia Sky broadcasts it as a row highlight, so that other clients may act on it.
  • Point at sky (coord.pointAt.sky) - Puts camera in free mode and points it to the specific direction.
  • Multi selection (table.select.rowList) - Gaia Sky does not have multiple selections so far, so only the first one is used right now.

Unimplemented features

The following SAMP functions are not yet implemented:

  • table.load.* - Only VOTable supported.
  • image.load.fits
  • spectrum.load.ssa-generic
  • client.env.get
  • bibcode.load
  • voresource.loadlist
  • coverage.load.moc.fits