Examples of Synoptic Date Blocking

  • Targets to be observed on specified dates:

      The visit dates of date-specified targets can be controlled with the SYN Dates parameter of the target list. If you wish the target to be observed on the civil night beginning May 2, 2020 then submit a target list with the SYN Date set to =20200503 (NOTE the change to UT date). This lets the RA know that this is the ONLY date that the target should be observed.

      You can further restrict the time of observation by invoking the Azimuth Restriction parameter of the target list. This instructs the RA to observe the target ONLY in its east or west track. To help prevent that being overlooked (as it is an infrequently used feature), state "East Only" or "West Only" near the beginning of the Comments field of the target list as well.

  • Targets to be observed in a strongly structured cadence:

      For a situation with e.g. orbital or pulsational phase filling, there are two approaches. The first first predates the enhanced TSL submission software. You would have to submit all of the visit window possibilities for each visit, having first eliminated any visits which are unfeasible by means of the observability tools.

      E.g., if you need one visit on any one of the following UT dates May 2, May 10, May 15; and two visits on any two of the following UT dates: May 3, May 11, May 16, and May 23, then create two targets, one single-visit with the SYN Dates entry being =20200502,=20200510,=20200515 ... and one double-visit with the SYN Dates entry being =20200503,=20200511,=20200516,=20200523.

      While the potential to submit or retract batteries of date-specific SYN Dates targets is unlimited, it takes a good deal of PI activity continually to rejig the target list in such a way, as visits are executed or bypassed, compounded by size of the program. By this point reconsider whether the automatic phase-blocking software offers a better solution.

  • Targets to be observed in a partly structured cadence:

      Set the SYN frequency entry in the target list to be RAND#-# where # are given in days. That sets the strict minimum cadence interval and a target for the maximum cadence interval. The RA will add a value within the RAND frequency range to the current UT date and place that in the SYN Dates entry of the target list. For example: If we observe a target on 20200301 that has a SYN frequency of RAND5-10, then the RA will update the SYN frequency to be >20200306 and the target will be synoptically blocked until 20200305. The PI should note that given the competition with other targets, and the progression of observing conditions and moon phases, there is no guarantee that the maximum spacing will not be exceeded. However the RA modified priority tactic increasingly strongly flags synoptics that overshoot their cadence upper bound, so there is partial feedback. The use of a minimum frequency of 0 will suggest to the RA that it is fine (but not required) to observe the target twice in a night (once in the East track and once in the West track). For targets far in the north or south which only have 1 track please use a minimum frequency of 1 or contact the RAs for more help.

  • Targets to be observed with minimally structured cadence:

      Letting the RA observe your targets when the conditions and TAC priorities warrant, will produce a fairly random sampling cadence within the bounds set by the annual rate of access to different sidereal times and by trimester discreteness. You can influence the cadence by explicitly setting the bounds to the range of target visit dates. The PI effects this via the SYN Dates and Comments entries of the target list. E.g., if a target should be observed within the window Mar 1-5 2020, civil date, inclusive, then the SYN Dates parameter should be >20200302-20200306 or >20200302,<20200306. (Note the change to UT date).

  • Targets with a known periodicity and explicitly intended phase coverage:

      For some programs it is desirable to achieve a particular phasing of observations, with respect to a known periodicity cycle. Examples are: observing only at selected phases (such as extrema), observing only away from selected phases (such as avoiding light minima), or observing so as to approximate a quasi-uniform phase coverage. See the phase-blocking (phase-filling) software discussion.

    Remember: making a target synoptic by invoking any of the abovementioned parameters will result in the target status being activated only in the provided date window, and being software-BLOCKED for the entire trimester duration outside that window.

    Last updated: Sun, 05 Aug 2012 03:53:49 -0500 caldwell

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