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[ 1 Time allocation principles ] [ 1.1 The OPT ] [ 1.2 Access ] [ 1.3 Scheduling ] [ 1.4 Observation constraints ] [ 1.5 Transients/Target of Opportunity observations ] [ 1.6 Data Proprietary Periods ] [ 1.7 Tape Storage ] [ 1.8 Other useful links ]

PIs or technical leads of projects are requested to assemble their observing blocks as soon as possible by logging into the Observation Planning Tool (OPT) at https://apps.sarao.ac.za/opt/observations using the same credentials used for proposal submission.

Time allocation principles

The MeerKAT time allocation may seem a bit ambiguous due to the uncertainty in actual overheads. The following is intended to clarify the reasoning, and why you may be requested to adjust your submitted schedule blocks.

Overheads are considered to be the time spent on calibrators and slewing (i.e. any time not spent integrating on the science targets). The percentage of overall requested time can vary based on the length of the schedule block, number of pointings and whether polarisation or other specialised calibration is needed, as described here: https://skaafrica.atlassian.net/wiki/spaces/ESDKB/pages/1498940282

The average observation overhead, considered across a full year of observing a varied science programme, works out to about 25%. In order to ease the proposal preparation process, an overhead of 25% can be assumed when requesting time. The total requested time on target is carefully considered during the feasibility and science reviews, and this is the key quantity in the time allocation. Observers are requested to minimise overheads, when setting up their schedule blocks, and to adhere to the allocated integration times on target.

For example, a proposal requested 8 hours on target, and assumed 25% overheads, leading to a maximum time request of 10 hours. However, once the schedule block is set up and the observation is simulated, the total duration of the block is 9 hours. This does not mean that the time on target should be increased to extend the block to 10 hours, since this is not necessary to achieve the science goal as per the approved project. Conversely, we may have a situation where the observatory has requested the observer to split the observation into shorter blocks in order to expedite scheduling, and the overheads increase to 30% when following the recommended calibration strategy. This would be considered acceptable in the cause of reducing scheduling idle time.

The OPT

Instructions on using the OPT are here. JSON files generated earlier during proposal preparation may be uploaded to this interface. Please use your new assigned Project ID in the form SCI-YYYYMMDD-XX-nn or DDT-YYYYMMDD-XX-nn and not the ID issued by the proposal submission system. Should you encounter any difficulties please raise a support ticket here.

Access

PIs of accepted projects will be given administrator rights for their project and may enable access for Co-Is by following these instructions. In some cases the PI may not be the corresponding author and might not be registered on the system. In these cases we request that the PI follow the instructions on the getting a SARAO account page, then raise a support ticket once this is done to confirm their account details. Please quote your SCI or DDT project ID.

Scheduling

MeerKAT does not generate its observing schedule long in advance. Once your schedule block has been submitted, it will be checked by the Astronomer on Duty, and added to the queue. Please ensure that your start LST range is as flexible as possible to ease scheduling. Ensure your track length is less than six hours unless scientific considerations require a full track in one run. Long tracks (8+ hours) are more difficult to schedule so, if possible, we request that observers split their tracks in half - into two schedule blocks, selecting suitable LST start ranges for a ‘rising’ track and ‘setting’ track in order to maximise uv-coverage.

Observation constraints

Observation constraints may be specified in the observation setup tab.

Users may use the ‘comments’ tab in the OPT to communicate constraints. Note that requests for night observations must be well motivated (generally at the proposal submission stage).

Transients/Target of Opportunity observations

In the case of observations based on triggered criteria, users are requested to prepare their schedule block as soon as possible and at the same time email scheduling@ska.ac.za, clearly stating how the approved triggering criteria for this proposal have been met. If an observation can proceed with fewer than 58 antennas, please let us know - it may be possible to schedule the observation sooner while some antennas are in maintenance. Continuum observations may run in a higher channelisation correlator mode if it expedites scheduling in the case of rapidly evolving transients. This will be communicated to the observer at the time of scheduling. Data can be binned to a lower channelisation prior to download.

Data Proprietary Periods

Observations requested through Director’s Discretionary Time (DDT) typically have a proprietary period of three months. PIs may also choose to waive the proprietary period.
Open Time proposals typically have a proprietary period of 12 months after the last observation has been obtained.
Proprietary periods vary for Large Survey Projects (LSPs) depending on observing seasons.

Tape Storage

Note that due to disk storage constraints, data will be moved off active disk storage to tape after six months. Restaging data to disk is possible but may be subject to significant delays. You are in any case advised to initiate transfer of your data as soon as possible to get started with reduction/analysis.

Due to the large volume of a typical imaging dataset, and the need to convert from MVF to MS format, the download link may take up to 2 weeks to generate.

External Service Desk Knowledge Base

Instructions to PIs of accepted proposals