ESA-Haystack Radio Telescope Simulator
Joachim Köppen Kiel July 2019
This is a simulator of the software with which the ESA-Haystack radio telescope on 1.4 GHz at ISU in Illkirch is controlled and operated to make radioastronomical measurements. It permits to make 'observations' of sky objects in the same way and to produce data in the same quality as the real instrument. The graphical user interface closely resembles the real thing, except for some features that make sense only in the real program. This is the version for spectroscopy in the 21 cm line of neutral hydrogen at the theoretical frequency of 1420.4057517667 (±...9) MHz.
The simulator produces spectra for a number of positions in the Galactic Plane which are based on real observations with this instrument.
The real instrument has these technical data:
Access to the simulator is organized in three pages: Operate, Output: Power, and Output: Spectrum. Here is a description of the controls:
Operate: this is the principal page, from which all operations are effected, and where all information are displayed.
The plot has also an important function: Click on a source will make the antenna move to that position and then track the source. The 'Track' button text will become blue to indicate this state.
Output: Power: when data are recorded, the total power summed up over the spectrum is added to this page. From here they may be copied and pasted into a text file for further interpretation. Each datum is composed of time [UTC], azimuth, elevation, power [dB]. When a large number of data are recorded - for a couple of hours, say - the browser may have problems showing all the data easily. Therefore, it might be advisible not to make recordings too long.
Output: Spectrum: when data are recorded, the spectra are added to this page. From here they may be copied and pasted into a text file for further interpretation. The format is almost identical to that used by the real software: each datum line is composed of time [UTC], azimuth, elevation, number of spectral bins, frequency [MHz] of the first bin, frequency step between two bins [MHz], followed by the powers of all the bins of the spectrum.
The HI spectra of the Galactic Plane
This is an overview of the spectra from the Milky Way's plane. Between
galactic longitudes 0 and 240° data were taken with the 9m antenna of DL0SHF.
These data are well consistent with the surveys obtained with the ESA-Haystack
telescope, as can be seen here.
The other longitudes, inaccessible from Europe, were observed with the 2.3m
diameter antenna at Grove Creek Observatory in Australia. A reduced spectrum is
represented by a sum of Gaussian components of different radial velocities
and velocity dispersions.
The data are shown as a false colour map of the flux as a function of longitude and radial velocity, and for a specified longitude, the spectra are also plotted in terms of antenna temperature. Since the emission is fairly extended, antenna temperature is equal to brightness temperature.