2130 RIQ Computation of the parallactic angles

[hugobuddel]

Faustine Cantalloube comments:

It appeared not clear when reading: are the parallactic angles computed inside or outside the pipeline ? Are they set as header keywords including START and END or as a mean - and with which precision ? Is the timestamp kept somewhere as well to make sure the information is redundant (this is critical for ADI-related processing).

https://jira.eso.org/browse/MET-2130

[hugobuddel]

In MICADO there is a separate drl function to calculate the parallactic angle because the headers only provide START and END. It is also not clear to me how this is done in METIS. See also #136

[gotten]

The ICS keywords in METIS-6639 - E-LIS-KUL-MET-1002 are missing the start and end time of the observation. Also no coordinates for the observatory itself. If these are not available from upstream (the ELT / TCS ?) they need to be included in the 1002 doc. There are several keywords related to rotation angles (TEL ROT OFFANGLE, INS DROT POSANG). Unclear whether these can be used to derive (or are equivalent to) the parallactic angle. These angles are currently only a singular position.

Accuracy of true north angle is still being studied in E-ANR-MPIA-MET-1095 draft document. It will depend on mechanical stability and calibration accuracy.

[hugobuddel]

There are many keywords missing from E-LIS-KUL-MET-1002. Since that document is not part of FDR, we decided to turn it around. We first define the keywords in the DRLD, and once that passes FDR, we add them to E-LIS-KUL-MET-1002.

So essentially we can just decide what we want and then make sure the keywords are available. Of course we need to coordinate, but we are essentially asked to be proactive. We should approach this as if we are in charge (because essentially we are). And you are the best person in our group to define what we need.

I think Faustina has been bitten by this before and wants to make sure the proper information is there. Which I think is both the best estimation of the parallactic angle from the ICS (and upstream), as well as enough information to calculate it independently.

Perhaps that is what we should answer:

We will make sure that the headers contain both the best estimation of the parallactic angle from the instrument/telescope, as well as enough information to calculate it independently.

That would give us some time to define it properly.

[gotten]

OK with your strategic answer.

[gotten]

Replied to RIX with:

We will make sure that the headers contain both the best estimation of the parallactic angle from the instrument/telescope, as well as enough information to calculate it independently. If possible both the start and end values.