Page History
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DH: GSC comes from 2MASS, not GAIA.
KS: does NIRSpec use 1.6" mask during target acq?
CP: yes. it's the biggest hole in the grid that we have
KS: what happens, with 1", when the point and shoot falls off the slit?
DH: 1.6" is not the one third of the time
KS: What happens when it does fall outside?
CP: with the currnet WATA mode, this would not be good.
– we may want to use the MSA instead
JF: can we do WATA and then follow with MSA if we miss it?
CP: that is not hte current setup. it might be better to just use MSA now.
TK : if we really only get 1" pointing accuracy, we need to find a new option, like PEAKUP stage.
JF: I will look into what happens if you miss the TA
DH: if you miss your TA (2 chances) then JWST will move onto the next visit and cancel the current visit
KS: for TSO, there is only 1 TA at the beginning of the visit
TK: NIRspec only tries once
DH: good point, MIRI does it twice.
PG: NIRISS also only tries once.
JS: check this: NIRCam might also only TA once
DH: be careful: the 2 tries to do not change the telescope pointing
– it is meant to address a cosmic ray event (or some such)
– it does not change the pointing
– if the TA cannot find something, then
JF: history of exoplnets .....
DH: for Spitzer, the intrapixel was the issue
JF:
KS: slit loss for nirspec could be a major issue for TSO
JF: survey of conversion ...
DH: 2 and 1 are not allowed. ngroups=3,5,7, ...
– the user can specify whichever they want. but APT will only do odd number
JF: MIRI can add JDox suggestion to use ngroups>=5 for TA.
KS: There may not be issues with ngroups>5 for MIRI
DH: it could be an issue for some targets, even with FND
SK: for stability, there may be an issue with dwelling while changing from TA filter to prism.
The FND TA filter is the further away from prism, which has the longest time to get the LRS prism.
– photons can hit the detector in that time frame
DH: We are in the Rayleigh-jeans, so Kmag may not reflect actual photons the detector
