WFCAM/UKIDSS SURVEY OPERATIONS

UKIDSS comprises five major surveys, some of which themselves have significant subsurveys which are well-separated on the sky. We employ the following definitions of the various components of the UKIDSS survey.

1. Survey - one entire UKIDSS survey, e.g. the LAS.
   
2. Project - one part of a survey programme (for example, one DXS field or one RA slice of the LAS). Defined mainly for operational and scheduling convenience as described later, and roughly corresponding to a PATT programme in the way it is treated by the database and supported by UKIRT scientists

Timescales

Monitoring of progress is done on three different timescales.

1. day to day, including adjustments made in the course of an observing night. The summit observer is responsible for in-night adjustments (such as flagging Observations and MSBs as bad); the UKIRT scheduler and support astronomers are responsible for adjustments to the queue made on the basis of the night report from the previous night.
2. short-term, defined roughly as the time taken to obtain data, ship to CASU, receive back data quality information (as required to implement repeats of given MSBs) and for the data to arrive in the science archive. Of order three weeks to one month.
3. long-term, defined as equal to or longer than the time for significant progress to be made on a given survey (greater than one month).

OMP database structure

Surveys are divided into projects cconsistent with a monitoring timescale of order one WFCAM block. Each project is given an individual "project ID" - for example, DXS sub-fields entitled u/ukidss/dxs1, u/ukidss/dxs2 etc. Bigger surveys such as the LAS are divided up into N-S strips, each of which is effectively a project and which is also allocated a separate project ID (u/ukidss/las1, 2 etc.). Uploading of projects into the OMP database is done on a flexible timescale; all projects for a 6-month period may be uploaded but the local survey manager may keep most of them disabled until they become relevant. In part this is to keep the OMP database size manageable and database query time to a reasonable level; in part to allow for easy monitoring of completion on the short-term timescale. Table 1 shows typical parameters of the Projects.

Table 1. Subsurveys and examples of component "projects" in the database
Survey	Subsurvey component	Example component ID	Upload or Enable/Disable Frequency
LAS	One N-S Strip	U/ukidss/las1	monthly, approximately two hours of RA range
GPS	One Dec/RA strip	U/ukidss/gps1	monthly, as for LAS
DXS	One DXS field (or its two-year plan subset), with a repeat count	U/ukidss/dxs1	One or two fields at a time
GCS	One cluster	U/ukidss/gcs1	one or more clusters at a time, RA depending
UDS	UDS, with a repeat count	U/ukidss/uds	whole survey always present in the OMP database; repeat count used

The UKIRT Query Tool is used to select MSBs to execute. Therefore no MSB is ever commenced in inappropriate conditions (i.e. not matched to the MSB's embedded requirements on photometric quality and seeing).

UKIDSS may specify lower seeing limits for surveys if required, and at the summit it is also possible to employ an hour-angle limit. Internal priorities are set by the individual Survey Heads according to their needs (e.g. top-down priorities in the case of a need for contiguity). Surveys operate in a partly manual, partly automatic manner with some input from the local survey manager and programme support astronomers. For example, given the large number of MSBs in some of the surveys, occasional direct intervention on the part of the survey manager is needed to instruct summit observers to prefer some particular survey at a given time. Such forcing is catered for in the Query Tool and OMP database.

The summit pipeline continually produces indexed information on observing conditions, including delivered seeing and photometric quality. This is used to set MSB constraints in the query tool and thus effectively filter the database for appropriate MSBs.

Observer instructions

Each survey is supported by a primary and secondary UKIRT support scientist, provisionally as follows:

The primary support scientist has the following responsibilities for their survey:

1. Supporting UKIDSS in generating the MSBs
2. MSB vetting (in as much as this is possible)
3. Monitoring pipeline output and DQ parameters the day after a night's observing. It is not expected that this item requires much more than checking that data were taken in appropriate conditions (i.e. that the pipeline data quality output was adhered to by the observer). In practice, the support scientist for each UKIDSS run takes more of a role in this.
   
4. Feedback to the PI (UKIDSS survey chair or their delegate)
5. Detailed interaction with the UKIRT survey manager where necessary
6. Training visiting UKIDSS observers
7. Observing. With its current level of support, UKIRT accounts for some 30% of the survey observing.

The secondary support scientist stands in for the primary in the event of absence or illness, etc.

All regular communication between JAC and UKIDSS must be done through the OMP feedback system. For each survey, UKIDSS nominates "P.I.s and Co-I.s" to whom each nights' worth of feedback entries are automatically emailed. These include the CSV, the Survey head, and the UKIDSS Survey Scientist. 

For information, the figure below shows an example of a project feedback page - in this case, the Co-Is are identified as not receiving every email the programme generates. There are two support astronomers - primary and secondary - and this is also the case for the UKIDSS surveys. For each UKIDSS survey, there is one such feedback page.

ANNEX 3: Communications between JAC and UK data centres