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Daily Reports (2026/01/06-13, NIKA2 run 78, Cryo run 90)

Observers on-site: Beth Jones, Michael Logue, Remi Adam, Tuan-Anh Duong

Astronomer-of-Duty: Stefano Berta Pool Manager: Angel Bongiovanni

Operators: Kike (day), Frederic (night)

Organization of shifts:
21:00-03:00 UT: Tuan-Anh
03:00-09:00-10:00 UT: Remi
09:00:15:00 UT: Beth
15:00-21:00 UT: Michael

Preparatory notes

Please fill the Table with the Ar1,2,3 focus values as follows. At best, make one table per day.

• Focus sequences
  Scan nr	Target	Ar2	Ar1	Ar3	Polarized?	Notes

Similarly, if any beam maps (total power) are taken:

• Beam maps (99 sub-scans)
  Scan Nr	Target	Focus	Notes

Pool-Account usage: Accounting of observing times

• Calibration observations like pointing, focus, and calib_1scan (the latter in case of NIKA2-Pol only, aimed at characterizing the instrumental polarization) which are conducted before and during project observations are part of the project time. Note that all proposals include such overheads in the time and sensitivity estimates. This holds for total power and polarimetry observations.

• Other calibration observations which are important for all projects like beam maps, skydips, or calib_1scan for absolute flux calibration may be accounted under the pool account (nikaX-YY, where X = s,w and YY = year).

• When conditions are unstable and it is unclear whether project observations make sense at all, calibrations may be accounted to the pool account.

Tuesday 6th January 2026

@9:30 UT: the team arrived safely to the telescope. Blue skies, low tau, strong winds.
Short briefing to share important mountain information and recommendations. We re-organize the shifts (see top of this page).

@13:30 UT: system checks finished, Dave goes back to Granada. Starting the rotation of the HWP required to reboot the DAQ few times and also the mppsync server.
NIKA2 system setup completed: DAQ running, HWP rotating, NIKA2 window open, PaKo running, QL monitors x6 running, make-imbf new/old running. We wait only for the wind to calm down.

@14:00 UT Alessandro and Martino ask for some time to remotely check the amplifier of the noisy Box C (Ar2). They think that this enhanced noise might be due to the polarization of the Box C amplifier, that needs to be re-set from time to time. Alessandro and Martino check the amplifier. In Alessandro's words: "The gain of the amplifier C is too low. (...) I could fix it by playing with the parameters of the amplifier C but now with the parameters that worked in June 2025 it is not working anymore (...) it seems that the third stage of the amplifier C (YL026, the one that we have installed in June) is not working. The gain must thus be much lower, and adding noise. Just the less gain doesn't explain what we observe", though.

@15:00-21:00 UT Michael + all. Taumeter tau < 0.1. The telescope is parked because of the high wind. We take the chance to have a long explanation about NIKA2 operations. In the next days we hopefully will be able to put in practice what we learned.

@21:00-03:00 UT Tuan-Ahn + Stefano. We start observing at 22:30 UT. It takes some time to set everything. We need to reboot crates 3 and 1, the DAQ and the HWP rotation. All good now. Lost KIDs: 18/7/12 in Ar1/2/3. The first pointing scan is at 23:05 UT: 20260106s17.

The secondary mirror (M2, subreflector) is a capricious tonight and sends errors at every scan, including tracks:

• we suspect that PaKo might be sending some wrong information. The PaKo green window seems to be missing some info.

• we reboot PaKo and set it up manually, because the ini.pako file cannot be edited with emacs even if we change the permissions to "rw". Weird. More specifically: the ini.pako file has project nikas-25 and the catalogs are all commented out. This should not affect M2, though!

• we try again with a new track scan (nr 21). It seems now to work... uhm, nope, subreflector "vertical 2" error again.
• we edit the ini.pako file with nano and we can modify it normally.
• we try a couple of scans with EMIR, without switching NIKA2 off. No M2 errors appear.
• we compare the nikaw-25 ini.pako to the nikas-25 ini.pako and they're identical. It was working in S25, it should work now too. Therefore the problem is not the ini.pako file.