ALMA Observing Tool

The ALMA Observing Tool (OT) will be the software tool that supports astronomers in constructing a full Observing Project for the ALMA Observatory. Basically, such Observing Programs will be submitted to the Observatory in two parts. The first is a Phase I Observing Proposal that will have its emphasis on the scientific justification of the proposed observations. The second part of the project is the Phase II Observing Program that can be submitted to the ALMA Observatory if observing time has been granted by the Time Allocation Committee (TAC) on the basis of the accepted proposal.

Central in the OT is the creating of a set of Scheduling Blocks (SBs) which are required to drive observing with ALMA. The SB is the smallest (indivisible) unit in ALMA observing that can be scheduled independently. It is self contained and usually provides scientifically meaningful data. The SB contains a full description of how the science target and the calibration targets are to be observed, and sets of SBs can be combined with a description for the post processing of the data, ultimately resulting in an image.

AT1+AT2+AT3Observing Tool
A typical display produced by the ALMA Observing
Tool (OT) using the Visual Spectral Editor. The
graphics shows the ALMA receiver bands and the user
selected positions for the basebands and sidebands.
Also,the atmospheric transmission curve is displayed.

In order to serve both less experienced and experienced astronomers, the OT will be equipped with two so called Views to make Observing Program preparations. It is intended that the main view on the ALMA system will be the Science View. As the name indicates in this View the user can concentrate on inputting the science requirements of their observing program: the area to be observed for each target, required sensitivity and frequencies. For most observing even experienced users should only need to use this view. The required SBs will be constructed by the system and the user will only be bothered with system parameters when this is absolutely necessary, in general detailed parameters will be determined from the science input.

It is recognized that for some programs, and indeed for developing new observing modes, an ALMA-experienced observer will need more. The System View (or expert mode) will provide such a user with a complete set of parameter fields that enable a detailed specification of each scheduling block: the observing process of science and calibration targets, including data acquisition and reduction recipes. These parameters include the frequency setting of the local oscillator, the upper and lower side bands, the correlator parameters and the selection of the basebands and subband sets within each baseband. Whichever View is used, SBs must be created.

An interesting functionality in the System View that has been added recently is the Visual Spectral Editor. This will help somewhat experienced users to carefully position LO frequency, and the frequency characteristics of the basebands configuration within the ALMA receiver band. In the figure a part of this editor is visible. It shows the upper part of the Visual Editor display with the all ALMA Frequency bands (note that these will not all be available; see also here ), the transmission curve of the atmosphere over the full ALMA observable spectrum (note band 6 has been selected), the setting to the LO frequency and upper and lower side bands, and one baseband selection. A later version of this tool will aid less experienced observers, without subjecting them to the detailed setup.

The development of the Observing Tool is a shared effort between the UK Astronomy Technology Centre in Edinburgh, ESO and the NAOJ, with science advice being provided from Osservatorio Astrofisico di Arcetri and the NAOJ.