Daily Reports (2026/02/17-24, NIKA2 run 79, Cryo run 91)

Observers on-site: Sunayana Bhargava, Andrés Zuleta, Vito Aberham, Miren Muñoz (until Friday), Albrecht Sievers (from Friday on)

Astronomer on Duty: Ioannis Myserlis (and Miren Muñoz on AoD training)
Pool Manager: Angel Bongiovanni

Operators: Joaquín Santiago (night), Sergio Amaya (day)

Organization of shifts:
21:00-03:00 LT: Sunayana Bhargava
03:00-09:00 LT: Miren Muñoz / Albrecht Sievers
09:00:15:00 UT: Andrés Zuleta
15:00-21:00 UT: Vito Aberham

Important

Focus offsets shall be measured on Ar1
Pointing offsets shall be measured on Ar2

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 ; nikaw-25 in this case).
When conditions are unstable and it is unclear whether project observations make sense at all, calibrations may be accounted to the pool account.

Focus and Beam maps accounting

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

Focus sequences (NOTE: Ar2 is very noisy and this might influence the A2 focus value)
Scans nr.	Target	Ar2	Ar1	Ar3	Pol?	Notes
20260217s127-131	Uranus	?	0.45	0.98	Y	started focus @ 0.25mm
s167-171	Uranus	0.57	?	?	Y	started focus @ 0.45mm
s172-176	Uranus	0.63	?	?	Y	started focus @ 1.3mm
s177-181	Uranus	?	1.62	1.86	Y	started focus @ 1.9mm
s203-207	3C84	?	1.35	1.55	Y	started focus @ 1.62mm
20260218s16-20	3C279	?	1.52	1.85	N	started focus @ 1.35mm
s23-27	3C279	?	1.55	1.75	N	started focus @ 1.85mm
s30-34	3C279	0.55	?	?	N	started focus @ 0.55mm
s38-42	3C279	?	1.66	1.90	N	started focus @ 1.55mm

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

Beam maps
Scan Nr	Target	Focus	TP (99 subscans) or Pol (95 subscans)	Notes
20260218s22	3C279	1.52	TP	Ar1
20260218s29	3C279	1.75	TP	Ar3
20260218s37	3C279	0.55	TP	Ar2

Tuesday, 17th February 2026

10:30-15:30: All observers arrived safely at the telescope. Weather prediction looks amazing for the week and we are all excited to make progress with the NIKA2 pool projects! Maintenance time.

15:30-21:00 all: Starting with NIKA2-Pol observations, project 084-25. Tuning good with 11/5/11 bad kids (Ar1/2/3).

Pointing, focus and calib_1scan (20260217s133, for IP) on Uranus. Focus difference between Ar1 and Ar3 seems to be increased to about 0.55mm. Let's see how it evolves this week.
1 rep on G139.9091 with stable sky (+/- 2 Jy/beam in Ar2).
Going back to Uranus for IP calib_1scan (20260217s145), no need to refocus.
2nd and last repetition on G139.9091 with stable sky (+/- 0.5 Jy/beam in Ar2).
Since 6pm local time, telescope oscillations alarm/problem appeared 4 times, interrupting the observations. Only finished scan 1/6 before another interruption.
Telescope oscillations problems continue and happen always after the 1st scan of the map.
To finish the last map of G139.9091 for project 084-25, we load each scan separately. We tried to send all of them in the queue and the problem still occurs after the 1st (individual) scan is finished. It seems that we need to restart the control system before every single scan is sent to the telescope! Oh god!
Right before the end of the shift telescope oscillations/stuck scan problem resolved with the intervention of AJ (thanks!). Let's hope for a smooth evening & night of NIKA2 observations.

21:00-03:00 Sunayana: Change to project 015-17, still in NIKA2-Pol mode. Sky conditions excellent (< 2 Jy/beam in Ar2) and opacity great (< 0.15).

pointing, focus and calib_1scan (20260217s183, for IP) on Uranus. Focus difference between Ar1 and Ar3 restored to previously expected value (0.24mm). Ar2 vs Ar1 focus difference about 1mm.
1 repetition on NGC2024S
Back to Uranus for IP calib_1scan (20260217s191), no need to refocus, Ar1 and Ar3 focus very good.
1 repetition on NGC1333S
Back to Uranus for IP calib_1scan (20260217s199).
Starting project 146-25. Pointing and focus on 0316+413 (3C84). Beam is a bit elongated but not too bad. Sky conditions remain stable (+-2 Jy/beam)
Calib_1scan (20260217s209, for IP) done on 0316+413 (3C84).
Doing a second calib_1scan (20260217s212, for IP) on another weakly polarised source (1226+023)
One repetition of S255IR
Calib 1scan (20260218s8, for IP) on the same source 1226+023. Beam still a bit elongated as before the science sequence. Sky conditions still very favourable at +-2 Jy/beam
Skydip calibrations (20260218s9)
Change to NIKA-2 total power mode

Tuesday, 18th February 2026

03:00-09:00 Miren: Starting total power (10, 5, and 14 bad KIDs). Opacity < 0.15 or ~ 0.15 during the shift.

Focus on 1253-055 (3C279) before each beammap (3C279), optimising focus for each array + pointing corrections. Ar1 beammap: 20260218s22. Ar3 beammap: 20260218s29. Ar2 beammap: 20260218s37.
Focus again for Ar1 and move to project 197-25. Started with a nearby source pointing (1807+698). Good sky conditions: opacity below 0.15, p2p +/- 1 Jy/beam @Ar2. Array1 beam: 11.1 x 11.6 arcsec. EDFN_CL3 is already at an elevation of 50 deg, so we start with 1 repetition on this source. The presence of clouds may explain the p2p of +/-7 Jy/beam @Ar2 we observe in the pointing scan at the end of the repetition.
We move to nika2w-25 for a skydip (20260218s53) and check again the stability with a pointing on 1807+698, p2p back to +/- 0.5 Jy/beam @Ar2. Beam for Ar1 11.4 x 12.7 arcsec, ready to resume project 197-25.
Project 197-25: 2 repetitions on EDFN_CL3.

09:00-15:00 Andres: Continue with total power, trying to focus first.

Focus and pointing scans for various targets at different directions give high tracking errors. Wind speed is increasing (spikes 1t 12-14 m/s).
Around 10:00 (local time) tracking errors too high to process with PIIC. Clouds pass by.
We change to EMIR to compare with its tracking error results.
We got an alert due to tracking errors, we will stop observations (10:06 UT).

15:00-21:00 Vito: