1 ATMOSPHERE [ASTRO\]ATMOSPHERE [INTERPOLATE|MAKE] Compute atmospheric emission, opacity, system temperatures, etc..., using input parameters provided by the user. Input parameters are the following SIC variables: TEMPERATURE Outside temperature ZERO_PRESSURE Pressure at sea level. AIRMASS Number of air masses WATER Precipitable water vapor FORWARD_EFF Forward efficiency GAIN_IMAGE Receiver gain ratio TREC Receiver temperature FREQ_SIG Signal frequency (in GHz) FREQ_IMA Image frequency (in GHz) These variables can be assigned using the SIC command LET. The additional input variables ALTITUDE Site altitude FREQ_SIG Signal frequency (in GHz) FREQ_IMA Image frequency (in GHz) are modified by the ASTRO OBSERVATORY and LINE commands. The output of the command consists in the following variables TRUE_PRESSURE Local pressure, derived from the site altitude and the sea level pressure by the scale height of 5.5 km. TSYS The system temperature in the signal sideband TAU_H2O The water vapor opacity TAU_O2 The dry atmosphere opacity (mostly due to Oxygen, but minor constituents like Ozone may also play a role) EMIS_SIG The atmospheric emission (Kelvin) in the signal sideband EMIS_IMA The atmospheric emission (Kelvin) in the image sideband PATH_SIG The atmospheric excess optical path length (mm) in the signal sideband PATH_IMA The atmospheric excess optical path length (mm) in the image sideband These variables can then be used to produce plots of atmospheric transparency, system temperatures, etc... ATMOSPHERE INTERPOLATE will do the same calculations, but interpolating the data from the binary table (logical name GAG_ATMOSPHERE). ATMOSPHERE MAKE filename nf freqmin freqmax will create the binary table filename.bin for nf frequencies between freqmin and freqmax (in GHz). 1 CATALOG [ASTRO\]CATALOG name [/VELETA] [/ALTERNATE] Open the catalog file specified by 'name'. Default file extension is ".SOU". The catalog is of the format used at Plateau de Bure. Some standard catalogs are available in the directory GAG_ASTRO : SIO.SOU contains SiO masers used for pointing. CONTINUUM_1.SOU contains "strong" continuum sources (Flux > 8 Jy) CONTINUUM_2.SOU contains weaker sources, still useable for pointing (Flux > 3 Jy). PHASE-2000.SOU contains the phase calibrators of Plateau de Bure (Flux > 0.1 Jy) The catalog format is described in the ASTRO manual and summarized in the subtopic FORMAT". /VELETA option will open the catalog file 'name'.CAT, assuming it follows the format of OBSINP catalogs in use on the 30 meter telescope. A file 'name'.SOU will be created in the current directory in the Plateau de Bure format, so that this option needs to be specified ONLY ONCE for each catalog. Fancy options such as SL0P, SB0P ... are not supported. /ALTERNATE option will open the specified catalog as a second catalog, only accessible through the "/ALTERNATE" options of commands SOURCE, HORIZON, and CONVERT. For instance, a catalog containing calibration or pointing sources may be opened as an Alternate catalog, while the objects to study are kept in the Current catalog, enabling easy switching between the two kinds of objects. CATALOG with no arguments will display the catalogs currently opened. 2 FORMAT In the Plateau de Bure format each source uses one line of the catalog file. Each line should contain the following consecutive keywords (some may be omitted): 1) Source name field: The source name field is a composite item which can accomodate several names for a single source. Names should be separated by a vertical bar ( | ) with no embedded spaces, e.g.: B0415+379|3C111 Each name must have at most 12 characters. 2) Coordinate system: 2 characters, optional, may be: EQ for equatorial coordinates. If "EQ" is given explicitely, then the Epoch keyword is mandatory. GA for Galactic II coordinates. EC for J2000 Ecliptic coordinates HO for horizontal coordinates DA for equatorial, present-day coordinates. 3) Epoch: needed for equatorial coordinates after "EQ" keyword. 4) Longitude-like coordinate: in degrees, except for EQ and DA where it should be in hours. Format is like hh:mm:ss.sss or dd.ddd or hh:mm.mmm 5) Latitude-like coordinate: in degrees, same format as above. 6) Velocity type: alphabetic code , such as "LSR", "HELIO" or "EARTH". HELIO actually means: referred to the Solar System barycenter. 7) Velocity: in km/second, in the corresponding reference frame (LSR, HELIOcentric, or EARTH=local). Default is zero. 8) Intensity type: Either "FLUX" or "MAGNITUDE" (optional) 9) Intensity: Either the Flux in Jansky or the magnitude (optional) The flux can be followed by a spectral index. 1 CONSTEL [ASTRO\]CONSTELL [/DRAW [m] [l] [s]] [/NAME] [/BOUNDARIES] Plots in the current FRAME with the current FONT, MARKER and PEN, the constellations, i.e., the main stars of all the constellations with a marker size adequately depending on the magnitude. The options are: /DRAW [m] [l] [s] "m" will cause markers at the star's positions to be plotted "l" will cause the constellations outlines to be plotted "s" will cause the star's names to be plotted (using current centering and character size) /NAME will draw the constellation's names /BOUNDARIES will draw the constellation boundaries (originally constant RA and DEC at 1875 epoch, they are precessed to the current epoch. The current code is VERY slow. Use with caution. This command makes use of the logical name GAG_CONSTELL which points to a GILDAS Table containing the stars positions and drawing codes, and GAG_CONST_BOUND which defines the constellation boundaries. 1 CONVERT [ASTRO\]CONVERT [Catalog_Name] [/ALTERNATE] [/J2000 [Obs_epoch]] [/PRECESS [New_epoch]] [/GALACTIC] [/FLUX fmin] [/NAME ncname [iname]] [/INPUT POS|FLUX filename pos] Change catalog format or epoch. Without any option (or with option /ALTERNATE) and without argument, this command creates an OBSINP-compatible copy of the 'name'.SOU catalog (or Alternate catalog if /ALTERNATE is specified) under the name 'name'.CAT. With the /J2000 and/or /PRECESS option, the command will precess the current SOU catalog to J2000 system, using the specified epochs for observation (Obs_epoch, default 1950) and final result (New_epoch, default 2000). The output catalog is 'Catalog_name'.SOU, and has the standard format. /FLUX create a copy of the current catalog with only sources of flux larger than fmin /NAME ncname [iname]: reserve ncname characters for names field. With iname.gt.0, a standard name (Jhhmmmsddmmm) is created and put in inameth positions in the list of names. /INPUT FLUX filename : will take fluxes from filename, which has itself the format of a catalog (both input catalog and filename are assumed alphabetically sorted) /INPUT POSITION filename dpos : will take positions from filename, if different by more than dpos arc seconds. Filename has itself the format of a catalog (both input catalog and filename are assumed alphabetically sorted) /ALTERNATE option : do the same operation with the Alternate catalog. 1 FRAME [ASTRO\]FRAME System [...] This command specifies the reference frame to be used for plots. System may be HORIZONTAL or EQUATORIAL (at epoch defined by TIME command) If no other argument is given, plotting is done in rectangular coordinates representing Azimuth Elevation or Right Ascension Declination. If other arguments are given, a Stereographic projection is used. - FRAME EQUATORIAL Ra Dec Size the projection will be centered on Ra and Dec (hours - degrees); Size in degrees specify the plotting range (ex 180 for a whole hemisphere: the default) - FRAME HORIZONTAL Az El Size same thing, but Az and El are in degrees. - FRAME HORIZONTAL Center will plot a hemisphere in horizontal system, where Center may be ZENITH, NORTH, EAST, SOUTH or WEST. 1 HEADER [ASTRO\]HEADER Write the UTC and LST times on top of plot, as well as the observatory coordinates. 1 HORIZON [ASTRO\]HORIZON h1 h2 ... [/SOURCE ... ] [/PLANET ... ] [/AIRMASS] [/FLUX Fmin Fmax] [/PROJECT] This command is used to produce plots of LST ranges of visibility, above specified elevations, of sources and planets. A line is drawn for all hours when the object is visible above elevation h1; tick marks and labels are provided for elevations h1, h2, ... (in degrees), or corresponding air masses values (with /AIRMASS option). Elevation values must be in increasing order, or airmasses in decreasing order. UTC axis is drawn on top of the plot. A label with date and observatory coordinates is plotted. /SOURCE will plot on one page all sources of the Current (by default) or Alternate (optionally) catalog. /SOURCE name1 name2 ... will be restricted to the specified sources /SOURCE NEXT n will plot the next n sources in the current catalog; (repeat this command to avoid over- crowded pages) /PLANET will plot on one page all solar-system bodies /PLANET name1 name2 ... will be restricted to the specified bodies /ALTERNATE with /SOURCE, will use the Alternate catalog. /FLUX Fmin Fmax restrict the search to sources with flux in the specified range. /PROJECT add the project name (for Plateau de Bure bookkeeping 1 Language ASTRO\ Language summary The ASTRO\ language contains commands to compute apparent source positions on the sky at any time(*) for any place on earth. ATMOSPHERE : Compute atmospheric parameters CATALOG name : opens a standard source catalog CONVERT : convert .SOU catalogs to .CAT or J2000 system FRAME : define plotting reference system LINE : plot frequency coverage for Plateau de Bure HORIZON : plot visibility hours of sources and planets HEADER : write time parameters on top of plot OBSERVATORY name : load observatory coordinates PLANET [name] : compute planet coordinates SOURCE [name] : compute source coordinates SET parameter value : enter some parameter value TIME [time [date]] : set computation time UV_TRACKS : plot interferometer UV tracks * Ephemerides must be available for the planets at this time. 1 LINE [ASTRO\]LINE Name Frequency Band [Lock [Center [Harm]]] [/MOLECULES File] [/SPECTRAL Unit Bandwidth IF_2] /WIDTH width [ASTRO\]LINE /SPECTRAL Unit Bandwidth IF_2 [ASTRO\]LINE /AUTO Plot rest frequency coverage of Plateau de Bure Interferometer. The command syntax is identical to that of the corresponding command in OBS. Name is a line name to label the plot Frequency is the center frequency in GHz Band should be USB or LSB Lock (optional) is LOW or HIGH Center (optional), the center IF2 frequency in MHz, default 350. Harm (optional), the harmonic number. The option /MOLECULES enables to plot the rest frequencies of several transitions, found in file File. This is a text file with entries: Freq 'chain' where Freq is the rest frequency in GHz and 'chain' the line name to be plotted by GreG, between single quotes. Example: 88.632 'HCN' 89.081 'HCO\u+' The option /WIDTH width is used to introduce a finite width (in km/s) for the molecular lines displayed. The option /SPECTRAL is used to overlay the desired spectral correlator configuration. Unit is the correlator unit number (1 to 6) Bandwidth is the bandwidth in MHz (10, 20, 40, 80 or 160) IF_2 is the center frequency (in MHz) of the unit in the second IF (in the range 110 to 590 MHz). With only the /SPECTRAL option, the corresponding unit overlay will be drawn on an existing LINE plot. Because only one synthesizer is used to generate the 1st and 2nd LOs, the IF frequency is slightly variable (between 1.500 and 1.550 GHz), and the Doppler tracking is correct only for the specified band (USB or LSB). The last specified source is used to get the Doppler shift. The image frequency doppler shift is wrong by at most 2.Ers/Harm, where Ers is the Earth rotation speed, or about 0.9 km/s, roughly 0.04 km/s at 86 GHz. THe option /AUTO is used to guess the line frequencies and spectral setup for Bure, given a set of variables: N_LINE int number of line frequencies N_CONT int number of continuum frequencies for each of N_LINE: LINENAME_i char line name of line table LINEVELO_i char velocity range (2 values: min, max in km/s) LINEFREQ_i dble line frequency (MHz) LINEVRES_i dble velocity resolution (km/s) for each of N_CONT: CONTTABLE_i char name of continuum table CONTBANDS_i char range of frequency bands for the continuum (min1 max1 min2 max2 ...) Output is also in a set of variables, used by setup writing procedures. look into LINE_* and SPEC_* variables. 1 OBSERVATORY [ASTRO\]OBSERVATORY longitude latitude altitude radius or [ASTRO\]OBSERVATORY Name Specify an observatory whose coordinates are known, or Enter the observatory geographic coordinates in degrees, and elevation in km above sea level. CAUTION: East longitudes are positive. The fourth argument is the radius of the Sun avoidance circle, in degrees. Known observatories are "BURE", "VELETA", "LASILLA", "SEST", "MAUNA_KEA", "JCMT", "CSO", "VLA", "KITT_PEAK", "EFFELSBERG", "PARANAL" (or its equivalent "VLT"), "HOPKINS" (or its equivalent "IOTA"),and "PALOMAR" (or its equivalent "PTI"). Example: OBSERVATORY 44:23:12.0 +45:09:57.9 3.987 30. A reasonable system default should be introduced in command file "GAG_UTIL:ASTRO_LOCAL.ASTRO". For known optical interferometers, the variable FREQUENCY is changed to reasonable values (1.0 to 2.5 microns typically). Use the command "LET FREQUENCY" to tailor the frequency to your needs. 1 PLANET [ASTRO\]PLANET [name] [/DRAW [...]] Compute the coordinates of a Solar System object. Known objects are: SUN, MOON, MERCURY, VENUS, MARS, JUPITER, SATURN, URANUS, NEPTUNE. By default, all known objects are plotted if visible. The Option /DRAW is used to plot the object symbol on the screen. The planet coordinates (apparent RA, apparent DEC, Azimuth and Elevation at time of computation) are typed on the screen. PLANET outputs also the geocentric and heliocentric distances of the object (in A.U.), the apparent minor and major diameters (in arc.sec.), the position angle of the central meridian (east from north, in degrees), the brightness temperature (in K), and the flux (in Jy) at the current frequency. The frequency may be entered either through command LINE or by updating variable FREQUENCY (in GHz). Arguments to /DRAW may be LINE, MARKER, SYMBOL, or FULL: LINE will draw a line from the previously computed position MARKER will draw a marker (GreG style defined by GREG\SET MARKER) at the computed position SYMBOL will draw the planet's symbol at the computed position FULL will combine MARKER and SYMBOL (the symbol will be offset one marker size above the computed position). If several arguments are given they will be used in sequence. 1 SET [ASTRO\]SET parameter value Enter a value for a parameter. Valid parameters are : - DUT1 which is (UT1-UTC) in seconds of time (from I.E.R.S.) - DTDT which is (TDT-UTC) in seconds of time (from I.E.R.S.) - AZIMUTH_REFERENCE which is either NORTH or SOUTH, and defines the azimuth to be zero in the North or South direction (to conform to local conventions). - FLUX Name Value Attribute the flux value Flux to the source Name (only for quasars or continuum sources which are not planets). This command is used when no planet measurement is available and/or as a redundant flux check on strong and well known quasars or W3OH for example. A * as flux value frees the source as reference source. - SET NAME Argument Define the naming convention for listing sources from the catalog. Sources in the catalog may have several names. This command define which name should be printed in commands SOURCE and HORIZON. Argument can be names of the source Reasonable system defaults may be introduced in the command procedure "GAG_UTIL:ASTRO_LOCAL.ASTRO". 1 SOURCE [ASTRO\]SOURCE [name [...]] [/DRAW [m] [l] [s] [f]] [/ALTERNATE] [/SUN] [/FLUX Fmin Fmax] Compute the coordinates of a Source from the Current catalog. If no name is specified, all sources of the catalog are selected. Source coordinates may also be specified in the command line, in the same format as the catalog file. The /DRAW option is used to draw the source name on the plot at its current position (Azimuth, Elevation). The source coordinates (RA, DEC, Azimuth and Elevation at time of computation) are printed on the screen, as well as the line-of-sight components of the following velocities: increasing. Arguments to /DRAW may be LINE, MARKER, SYMBOL, or FULL, as for command PLANET: LINE will draw a line from the previously computed position (SOURCE or PLANET) MARKER will draw a marker (GreG style defined by GREG\SET MARKER) at the computed position SYMBOL will draw the source name in capitals at the computed position FULL will combine MARKER and SYMBOL (the name will be offset one marker size above the computed position). If several arguments are given they will be used in sequence. /ALTERNATE will direct the search to the Alternate catalog. /SUN will also list the sun avoidance limits /FLUX Fmin Fmax will select only sources with flux densities in the specified range. Marker sizes will be proportional to the (logarithm of the) flux. /PRINT option will suppress the printing of Az and El, and print the source characteristics as in catalog instead. 1 TIME [ASTRO\]TIME [time [date]] [/ZONE Z] [/UT1] [/TDT] [/NODRAW] Specify the time-date of computation. Time is normally understood as UTC ; options /UT1 and /TDT may be used to change this to UT1 or TDT. The time format is HH:MM:SS.SSS, and the date format is DD-MMM-YYYY. Time and date default to current system time. Local civil time may be input instead, in conjunction with the option /ZONE z, where z is the difference in hours between UT and local civil time (use /ZONE 2 on Plateau de Bure in summer, 1 in winter). By default, if the sun is visible, a sun avoidance circle is plotted. It can be suppressed using the /NODRAW option. The radius of the sun avoidance circle is now 30 degrees on Plateau de Bure. 1 UV_TRACKS [ASTRO\]UV_TRACKS station1 station2 [station3 [...]] [/FRAME [size]] [/HOUR_ANGLE Hmin [Hmax]] [/TABLE [Name]] [/HORIZON Elmin] Plot interferometer UV tracks for the most recently called source. Station coordinates are searched for in the file ASTRO_STATIONS. Stations should be referred to by a mnemonic (e.g. E03, W00 ...). A sketch of the interferometer described by ASTRO_STATIONS is also drawn. Option /FRAME should be used to start a new UV coverage. It clears the plot, draws the box, and open a new table if /TABLE is present. Option /HORIZON specify a minimum elevation (in degrees) for the source. Option /HOUR_ANGLE can be used to limit the hour angle coverage. Default is from source rise (above the minimum elevation) to source setup. Hmin and Hmax are in decimal hours. Option /TABLE can be used to write the sampling function (UV coverage) on a UV table for further processing such as producing beams using the task UV_MAP. Name should be specified only if option /FRAME has been set. The box labelling is in meters. A double labelling in kilo wavelengths is drawn if variable FREQUENCY (observing frequency in GHz) is defined. Switching to the VLT by the command "OBSERVATORY VLT" defines FREQUENCY to some 1 micron (300 THz). Some labellings are then in wavelengths (microns). Switching between files describing interferometer stations can be done inside ASTRO by redefing the ASTRO_STATIONS logical variable using the command SIC LOG ASTRO_STATIONS "path/to/the/desired/file" The BURE stations are described in the file ephemeris/astro_stations.dat (and accessed by default on most ASTRO installs, or otherwise by SIC LOG ASTRO_STATIONS GAG_ASTRO:astro_stations.dat) The VLT stations are described in the file ephemeris/vlt_stations.dat (and accessed by SIC LOG ASTRO_STATIONS GAG_ASTRO:vlt_stations.dat) The IOTA stations are described in the file ephemeris/iota_stations.dat (and accessed by SIC LOG ASTRO_STATIONS GAG_ASTRO:iota_stations.dat) The PTI stations are described in the file ephemeris/pti_stations.dat (and accessed by SIC LOG ASTRO_STATIONS GAG_ASTRO:pti_stations.dat) 1 END