Data formats and online quick-look

Details on the FITS file structure are given in a separate document. Download it here: pdf

Waiting for a comprehensive GUI which is going to include also a real-time preview of the data under acquisition, users are provided with two different tools in order to inspect the data produced by the TPB and XARCOS.

If writer is MANAGEMENT/FitsZilla

When acquiring FITS files through a schedule, there is an IDL tool available for the almost-realtime quick-look of the saved data.

Open a terminal on escsConsole. Launch IDL:

$ idl

At the IDL prompt, compile and run the program

IDL> .r fitslook
IDL> fitslook

The last completed FITS file (i.e. the most recent subscan carried out, either being a TP or a spectral one) will be displayed.


The program automatically identifies the recorded sections and plots them all. If you are using the multi-feed receiver with the aim of actually exploiting only the central feed, adjust your schedule so that only sections 0 and 1 are enabled, otherwise all the sections will be recorded and displayed.

The plots show the proper file content, according to its continuum or spectral nature. Read all the program options using:

IDL> fitslook, /help


By default, fitslook displays raw data (in arbitrary counts). Data streams in antenna temperature are available - and selectable - only for the TPB and under the condition that a Tsys has been correctly acquired prior to the execution of the scan.

Quick-look of a continuum OTF scan acquired with a single-feed receiver

When performing ON-OFF spectral observations, users might also choose a different quick-look, displaying the (ON-OFF)/OFF result obtained by integrating all the subscans present in the last completed scan. Users must specify the duty cycle, e.g. ‘3:3:1’ if each scan is composed by 3 on-scans, 3 off-scans and 1 cal-scan. Zero values are accepted. To invoke this program:

IDL> .r onoff
IDL> onoff, dutyc='[N_on]:[N_off]:[N_cal]'

If wanting to display the spectra vs the topocentric radial velocity, use:

IDL> onoff, dutyc='[N_on]:[N_off]:[N_cal]', xtype='vel'
Quick-look of the (ON-OFF)/OFF scan, acquired with XARCOS in XK00 mode

Click on the above images to open the zoomable version.

Please report any problem/request about these tools, which are constantly under development.

If writer is MANAGEMENT/Point or MANAGEMENT/CalibrationTool

When data are acquired – both manually or through a schedule – using the Point or CalibrationTool writers, the quick-look must be performed using the CalibrationToolClient. Open a terminal on escsRemote and use the command:

$ calibrationtoolclient  [componentName]

where componentName is either MANAGEMENT/Point or MANAGEMENT/CalibrationTool. A graphic window will appear. Its content is given in the following figure.



In this client, the subscan currently being acquired is shown in real-time (upper plot), even if in a low-res version. Under this display, the last completed subscan - in its full sampling - is shown.