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Source
Figure 5.1:
The Source panel in the Field Setup form of the Science Goal.
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- Source Name: The source name. The source names should only contain the following characters: a-z, A-Z, 0-9, -,+, _ or a . (full stop). Characters other than these will be removed or replaced when the project is validated.
- Resolve: Fill in source details by searching for the entered source name in SIMBAD or NED. SIMBAD is checked first and then NED if no match was found. Check the details very carefully! Note that so-called IAU format e.g. B0218+357, is no longer allowed - an acronym must be placed before the coordinates e.g. JVAS B0218+357.
- Choose a Solar System Object: A number of solar system objects are recognised by the telescope control system and can be selected here. It is also possible to enter an ephemeris for any non-sidereal source. The source coordinates and velocity definitions are not displayed if a solar system object is selected as the system that controls the observations has detailed ephemeris information for each object.
- Name of Object: Recognised objects are:
- Stars: The Sun.
- Planets: Mercury, Venus, Mars, Jupiter, Saturn, Uranus,
Neptune.
- Satellites: The Moon, Ganymede, Callisto, Io, Titan.
- Dwarf planets: Pluto, Ceres.
- Asteroids: Pallas, Juno and Vesta.
- Ephemeris: Load a JPL HORIZONS format ephemeris.
- Source Coordinates:
- System: Only FK5 J2000 is formally supported by the telescope control system. If Galactic coordinates are entered, changing the system will cause the OT to convert the coordinates. This only works between Galactic and FK5.
- Sexagesimal display?: Coordinates in FK5 or ICRS will be displayed in sexagesimal format if this is ticked (default). Unclicking this will allow input in degrees for these systems.
- RA: Source Right Ascension. Default input formats are sexagesimal for FK5 and ICRS and degrees for everything else.
- DEC: Source Declination. Ditto.
- Parallax: Source parallax. Note that negative values are possible when resolving the source using an external server. This is due to the parallax being small compared to the measurement error.
- PM RA: Proper motion in the R.A. (cross-declination) direction. Units should be milliarcsec/yr. Proper motions are used to calculate the current source position assuming that the FK5 position refers to Epoch J2000.
- PM DEC: Proper motion in the declination direction. Units should be milliarcsec/yr.
- Source Radial Velocity:
The radial velocity of the source can be entered as either a velocity or a redshift. It is used to convert source rest-frame frequencies to their observable (sky) equivalents. The full set of options are:
- Velocity: Upon entering this, the redshift will also be set according to the Doppler Type (velocity definition). For Single Continuum setups, automatic SB generation will set the velocity to zero (in the SB only).
- Doppler Frame: A number of options are available: barycentric, lsrk, topocentric and lsr. Heliocentric can be chosen, but is not currently supported and during SB generation will be converted to barycentric (these differ by a maximum of approximately 12 m/s). If the frame is changed, no conversion is performed of an already-entered velocity/redshift. If lsrk is selected, the user-entered spectral window frequencies are converted to the barycentric frame when calculating tuning solutions.
- z: Redshift. Upon entering this, the velocity will also be set according to the Doppler Type (velocity definition). For Single Continuum setups, automatic SB generation will set the redshift to zero (in the SB only).
- Doppler Type: This sets the velocity definition (radio, optical or relativistic). Changing this will make the velocity agree with the entered redshift.
- Target Type: The supported observing patterns: ``Individual pointing(s)'' and ``1 Rectangular Field''. All sources in a Science Goal must use the same Target Type.
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Up: Field Setup
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The ALMA OT Team, 2015 Sep 03