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: Fri, 29 Dec 2023 12:52:31 +0000 stevenj
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