Defining Your Project's PB and SB(s)

There should be at least one project in your tree (if not, use FILE - CREATE NEW - NEW PROJECT) with, when you expand it using the plus-icon in the icon menu, a PB, and possibly a SB and a scan. Click on your project, especially if it has no plus-icon in front of it (and thus is not loaded into memory), and give it some descriptive title if it has not been filled in from the PST information. Similarly, click on your PB and name it.

Each PB is defined for an observing trimester, typically a single VLA array configuration with some hybrid configuration and move time configurations. For your PB, if not transferred from the PST, select the array configuration for which this PB is valid by dragging the array configuration name from the right hand side column to the left hand side column. More than one (consecutive) array configurations, or "Any", can be specified. If your project spans more than one clearly different observing runs per trimester, e.g. some southern sources in BnA array and some more northern sources in B array, simply add more PBs to this project using FILE - CREATE NEW - NEW PROGRAM BLOCK. The table at the bottom is a read-only, sortable administrative table. It keeps track of the total time scheduled in the SB(s) in this PB.

Create a first SB if necessary: FILE - CREATE NEW - NEW SCHEDULING BLOCK. When you next click on the SB, you are presented with three tab-pages in the main editing window (Figure 4.2). In the first tab ("SB Details"), name your SB and select whether it is a fixed-date SB or a dynamic SB - the tab-page will change with different scheduling constraints depending on the choice made; they should have self-explanatory labels and fly-over help tool-tips.

Figure 4.3: Web browser screen shots of the SB details page, bottom portion.

For fixed-date allocations you may have to fill out the starting day (VLA day, i.e., modified Julian day number on the VLA schedule) and LST time of your allocation. To schedule in UT time, e.g., for VLBI scheduling, you can use the UTC toggle-box. The "Array Starting Position" is an option to aid you in anticipating a worst case scenario of the antenna wrap, or to calculate the slew time in the unlikely case that you know where the array will be pointing at the end of a previous observation. Only for the latter you may choose "Equatorial" to enter a (J2000) Right Ascension and Declination, but for the former choose "Horizontal" to enter an Azimuth and Elevation of the anticipated array starting position.

For dynamically allocated observing time you are asked if there are any scheduling constraints. Possible constraints are a range of possible (or convenient) LST starting times, a first date of possible observations, and a starting position of the array. Other constraints deal with the weather at the site. Defaults for weather at specific bands are given in the table; see Figure 4.3. Select the description of the weather constraints that you want to apply, or specify your own constraints (supply both wind and atmospheric phase limits). The antennas will stow when the wind speed reaches 18 m/s). Consult Appendix A for more on SBs for dynamically allocated observing time.

This tab-page also contains a field in which you can communicate your notes, requests, concerns, other constraints, etc, to the operator. If your observations for this trimester include sources that cannot be observed in one consecutive time interval in the time allocated, or if you have more than one fixed-date allocations, you can define different SBs for the different LST ranges or fixed-dates, again by using the menu strip at the top: FILE - CREATE NEW - NEW SCHEDULING BLOCK. If your observing runs are very similar, simply copy the SB and adjust the new SB as required (or increase the repetition count).

The other two tab-pages are not relevant at this stage and will be described below. You are now ready to start making scans in this SB.