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Knowledgebase: ALMA Observing Tool (OT)
What do the time estimates in the summary PDF page generated by the OT refer to and how are they calculated?
Posted by Suzanna Randall, Last modified by Rein Warmels on 15 March 2017 04:01 PM

The PDF proposal summary generated by the OT reports three time estimates: the total time required on the 12-m Array for all configurations, the total ACA (7-m Array plus total power) time, and the non-standard mode time required on the 12-m Array. Since the 12-m and the ACA Array are queued for observations separately and can be observed simultaneously, the time taken into account for the proposal assessment is the 12-m time. A more detailed breakdown of the times can be brought up with the 'Time Estimate' button in the Control & Performance editor on a per Science Goal basis, or viewed for the entire project by clicking on the clock icon in the OT toolbar.

For most projects, the total time for a Science Goal is calculated in detail based on the requested sensitivity for the most extended 12-m configuration required (including all pointings, tunings, calibrations and overheads), and then this is multiplied by a configuration-dependent factor for the more compact 12-m Array configuration required (if any), and the ACA 7-m and Total Power (TP) Arrays. The total ACA time is given by the TP time if TP observations are scheduled and by the 7-m Array time if not, under the premise that these arrays can be operated in parallel. Using the TP Array without the 7-m Array is not allowed. For stand-alone ACA observations the time required is computed based on the sensitivity requested and the collecting area of the 7-m Array.

For VLBI and Solar observations, a 12-m Array time request (including all calibrations and overheads) is directly entered by the user into the OT rather than being computed based on a sensitivity goal. For Solar observations, ACA 7-m and TP times matching those of the 12-m Array are automatically added.

You can override the OT's time estimates in the Control and Performance editor. The value entered must be the total time required for the most extended 12-m Array including all calibrations and overheads, and the time override must be fully justified in the Technical Justification. Time overrides apply to the most extended 12-m Array; the resulting time for any more compact configurations will be computed by the OT using the factors described above.

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