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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 on Duty: Stefano Berta (SB)
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

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)
  Scan nr	Target	Ar2	Ar1	Ar3	Polarized?	Notes
  20260107s29-33	Uranus	out	0.6	0.8	yes	using old make-imbf, Ar2 out of range; started at 1.2 mm
  20260107s55	3C273	-0.18			yes	Using A2 and shift the value by 0.6 to center on A1 b/c the old make-imbf is slow
  20260107s86	1807+698	-0.1			no	Using A2 and shift the value by 0.6 to center on A1 b/c the old make-imbf is slow
  20260107s97-101	1253-055	out	0.7	0.94	no	Ar2 out of range, started at 0.8 mm, using new make-imbf again
  20260107s110-114	MWC349	out	0.8	1.0	no	started at 1.0 mm
  123-127	2251+158	out	out	0.5	yes	started at 1.1 mm -> repeat
  128-132	2251+158	out	0.25	0.45	yes	started at 0.5 mm
  148-152	2251+158	out	-0.07	0.2	yes	started at 0.5 mm
  155-159	2251+158	out	0.0	~0.22	yes	started at 0.3 mm
  160-164	2251+158	-0.9	0.0	out	yes	started at -0.2 mm; during the last scan, we are in the clouds
  165-169	2251+158	-1.0	~out	out	yes	started at -0.4 mm; we're still in the clouds
  172-176	Uranus	-0.24	0.63	0.8	no	started at 0.5 mm; Ar2 and Ar3 based on FWHM only
  189-193	Uranus	out	0.69	0.9	no
  201-205	Uranus	out	0.6	0.9	no	started at 0.6 mm
  5-9	Uranus	out	0.36	0.58	no	started at 0.6 mm
  20260108s24-33	3C 273	-0.63	+0.33	+0.60	no	done using 2 sequences starting at +0.3 and -0.2 given the large difference. Stable/reliable results
  20260108s35-44	3C 279	-0.65	+0.35	+0.59	no	done using 2 sequences starting at 0.0 and 0.5 given the large difference. Stable/reliable results
  81-85	3C 279	-0.5	+0.4	+0.63	no	started 0.3 mm; Ar2 FWHM only
  95-99	MWC349	-0.18	+0.65	out	no	started at 0.2 mm; Ar1 FWHM only; need to re-do to catch Ar1 and Ar3 properly
  100-104	MWC349	-0.15	+0.85	+1.0	no	started at 0.6 mm; Ar3 FWHM only
  118-112	2230+114	-0.41	+0.40	+0.65	yes	started at 0.4 mm; Ar2 FWHM only
  141-145	Neptune	out	+0.30	0.02	yes	Neptune not bright enough: started at 0.4mm; Arr1 excl. FWHM (out)
  146-150	2251+158	out	+0.24	0.07	yes	started at 0.4mm
  166-170	Uranus	-0.24	+0.70	+1.0	yes	started at 0.5mm; Ar2 FWHM only; Ar3 by eye (bad fit)
  201-205	Uranus	0.32	out	out	yes	started at 0.7mm
  206~210	Uranus	0.35	+1.4	out	yes	re-do at 1.1mm
  1-5	Uranus	0.59	+1.55	+1.9	yes	started at 1.4mm
  20260109s23-27	Alfori	out	+1.34	+1.55	yes	Faint source, thus not the best
  20260109s30-39	3C 273	+0.25	+1.25	+1.47	yes	done in two sequences starting at 1.55 and 0.8. should be good
  20260109s42-46	3C 279	0.3-0.4	+1.25	+1.46	yes	starting at 1.2. almost out at 2mm, not super reliable there
  20260109s53-57	3C 279	+0.35	+1.35	1.4-1.5	yes	starting at 1.0. Almost out for A3, not super reliable there
  20260109s91-95	3C 279	+0.4	+1.4	1.65	no	bad sky conditions
  102-106	1757-240	+0.55	out	out	no	start 0.5mm; variable sky conditions and low elevation
  107-111	1757-240	+0.5	+1.4	+1.6	no	start 1.5mm; variable sky conditions and low elevation; Ar2 FWHM only
  118-122	MWC349	+0.67	+1.6	+1.85	no	start 1.5mm; Ar2 and Ar3 FWHM only
  131-134	2251+158	+0.5	+1.15	+1.45	no	start 1.5mm; attempt in thin variable cloud - scan 131 unusable, 134 poor; Ar2 FWHM only
  145-149	2251+158	+0.25	+1.3	+1.65	yes	start 1.0mm; Ar3 fwhm only
  20260110s2-6	Uranus	+0.4	+1.35	out	no	start at 0.8mm; Ar1 fhwm only
  20260109s23-27	3C 273	+0.34	+1.4	out	no	start at 1.0
  127-131	1757-240	out	+0.65	+0.9	no	start at 1.3mm
  141-145	MWC349	+0.02	+0.9	+1.3	no	start at 0.8mm; Ar2 FWHM only, Ar3 dubious
  153-157	2251+158	out	+0.6	+0.8	yes	start at 1.0mm
  173-177	Neptune	out	+0.41	+0.6	yes	start at 0.6mm; Ar1 almost suspiciously perfectly aligned
  193-197	Uranus	0.2	1.1	1.4	yes	start at 1.0 mm Ar2 marginal, Ar3 FWHM
  227-231	Uranus	0.4	1.4	out	yes	start at 1.0mm; Ar1 FWHM only, Ar3 not covered
  253-257	Uranus	0.8	1.3	1.53	yes	start at 1.4mm;
  20260111s20-24	0851+202	0.35	1.3	out	no	start at 1.3mm;
  20260111s32-36	1641+399	0.4	1.25	1.54	no	start 1.2. At the limit of being out for A2
  75-79	1757-240	out	1.15	1.4	no	started at 1.2 mm
  85-89	idem	0.15	1.3-1.5	out	no	started at 1mm; Ar1 bad coverage -> re-do
  90-94	idem	out	1.35	out	no	started at 1.3 mm
  116-120	2251+158	out	out	0.45	yes	started at 1.1 mm -> re-do
  121-125	2251+158	-0.76	0.2	0.48	yes	started 0.4 mm; Ar2 FWHM only
  145-149	2251+158	0.0	0.85	1.07	yes	started at 0.8 mm, Ar2 FWHM only
  172-176	Uranus	0.5	1.4	out	yes	started at 1.3 mm
  199-203	Uranus	0.8	1.29	1.53	yes	started at 1.4 mm
  20260112s4-8	Uranus	out	1.2	1.4	yes	started at 1.29 mm
  20-24	3C84	out	1.15	1.36	yes	started at 1.2 mm
  27-31	3C286	0.4	1.25	1.4	no	started at 1.2 mm; Ar2 FWHM only
  38-42	3C279	0.25	1.25	out	no	started at 0.9 mm
  47-51	3C279	0.45	1.35	1.57	no	started at 1.2 mm; Ar3 FWHM only
  55-59	3C279	0.55	1.35	1.60	no	started at 1.4 mm; Ar2 FWHM only
  77-81	1807+698	0.50	1.30	1.55	no	started at 1.3 mm; Ar2 FWHM only
  90-94	3C279	0.3	1.25	1.45	yes	started at 1.1 mm; Ar3 FWHM only
  142-146	2251+158	0.2	0.8	1.2	yes	started at 0.6 mm; Ar2 FWHM only; Ar3 really v. dubious
  176-180	Uranus	0.5	1.5	1.7	yes	started at 1.2 mm; Ar2 and Ar3 marginal
  200-204	Uranus	0.6	1.6	out	yes	started at 1.3 mm

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
  20260112s44	3C279	0.26 (Ar2)	99 TP	"Stuck subscan" alarm at 96, false alarm b/c it finishes as expected (see details below); the new make-imbf gets stuck.
  20260112s52	3C279	1.36 (Ar1)	99 TP	"Stuck subscan" alarm at 97, false alarm b/c it finishes as expected (see details below); the new make-imbf gets stuck.
  20260112s61	3C279	1.6 (Ar3)	99 TP	"Stuck subscan" alarm at 97, false alarm b/c it finishes as expected (see details below); the new make-imbf gets stuck.

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-Anh + 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 conflicting information.

• the PaKo green window seems to be missing some info? We're not 100% sure, tbh.

• 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 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. Besides, it was working also in W25 in the December pool week. Therefore the problem is not the ini.pako file.
• we edit the NIKA2 ini.pako file with nano and we can modify it normally. We fix the project and un-comment one catalog.
• we try a couple of scans with EMIR, without switching NIKA2 off. No M2 errors appear. The chopper does not work, though, not even in manual mode.
• sending an EMIR calibration with a manually changed Z-focus position in EMIR produced again the M2 error
• we try a sequence of short EMIR scans with Z-focus of +0.5, +1.0, +1.5, -0.5, -1.0, -1.5 -2.0 mm and no M2 error appears. Maybe these movements have unlocked something that was obstructing M2?
• side note: today's temperature reached -17 C
• we switch again to NIKA2 and try again. Focus Z=1.0 X=1.9 Y=-0.78 mm. Immediate M2 error
• new test
  • we comment out the XY focus offsets in the NIKA2 ini.pako file

  • we start PaKo again and perform a track on Uranus. All fine, no M2 errors. We switch PaKo off.

  • we comment out only the Y focus offset in the NIKA2 ini.pako file

  • we start PaKo again and perform a track on Uranus. All fine, no M2 errors. We switch PaKo off.

  • we comment out only the X focus offset in the NIKA2 ini.pako file

  • we start PaKo again and perform a track on Uranus. All fine, no M2 errors. We switch PaKo off.

  • we keep the XY focus offsets in the NIKA2 ini.pako file, as in the very beginning.

  • we start PaKo again and perform a track on Uranus. All fine, no M2 errors.

  • what just happened??? it's all fine! 2 hours lost out of this problem and we don't know how we solved it and what we solved. Sigh.

Now the observations can start. But the DAQ has lost part of Ar3. We tune again. After 4 tuning with Boxes P and Q completely lost, we stop the HWP rotation and reboot the DAQ. KIDs lost: 15/7/12. We finally start the observations at 1:09 UT

Obviously the new make-imbf ain't working. I try to produce by hand the imbf of scan 26 and it tells "LD_LIBRARY_PATH unbound variable". Same for some old_ldpath. This was with Stefano's account. We try with the operator's account. It gives the same message. We have to work with the old one for now. We're in polarimetry and we should focus on Ar1 -> very slow. Perfect weather!

Not bad this NIKA2 2026 start! We had every possible hic-hup in one night. The next 6 weeks can only be smooth

Pointing, focus, calib_1scan on Uranus (although now at low elevation). 1 rep on NGC2264d and one calib_1scan on 3C286

Wednesday 7th January 2026

03:00-09:00 UT Remi

• Start with pointing on 3C286, with the goal of doing calibration on 3C286, 3C273 and 3C279 (in polarization mode).
• The imbits files are very long to create. Cannot reduce the pointing. We lose 30mn of time due to this issue.
• WARNING! On A2, Box C is extremely noisy.
• A focus is needed. Go to 3C 273 and focus.
• Do calib_1scan on 3C273 and 3C279.
• Stefano zzZzZZ switches to total power. Lost KIDs 12/8/8
• Pointing on 1807+698. The beam is reasonable at 2mm.
• Switch to project 197-25.
  • Repetition 1 on 1st target.
  • Pointing on 1807+698, beam acceptable (17x19).
  • Repetition 2 on 1st target.
  • Pointing on 1807+698, beam acceptable (17x19).
  • Repetition 3 on 1st target.
  • Pointing on 1807+698, beam at the limit (17.2x20). Focus on same source. Set focus 0.5 (using A2 and accounting for 0.6mm shift to A1). Pointing again. The beam is still not great at 2mm.
  • Repetition 4 on 1st target anyway.

09:00-15:00 UT Beth + Stefano

• We let Remi complete the 4th repetition of 197-25 (1st target)

• @09:30 the new make-imbf is back!!! Thank you AJ, we love you <3

• 166-25 pointing, focus, pointing, one rep. on GC2
• The cryostat was not on level attente! now switched it on.
• skydip + calib_1scan on MWC349, NGC7027 and CRL2688 (scans 108, 116, 117, 118)
• There are some high clouds passing by, +/- 5 Jy/beam variation. Therefore we decide not to switch to NIKA2-Pol and to keep going with total power.

• Pointing before continuing 197-25: variability now +/- 1 Jy/beam so Stefano and Kike go to swap to polarisation after all

• we switch to NIKA2-Pol. KIDs lost 15/10/17

• @11:55 we swap to 139-25, single target project. Bad focus on 2251+158 repeated. 2251+158 (and when up later, Neptune) will be Az >100deg whilst science target at <30deg so will need full wrap with every focus and calib_1scan

  • calib_1scan on 2251+158 (completed just before crossing wrap limit)
  • Pointing on 2254+617 - extended, use SMA_0102+584 next time
  • Execution 1/18 on HH288 (45mins), started 2/18 second but aborted at 50% completion for cloud
  • calib_1scan on Neptune and 2251 taken in cloud, tau 0.27
  • point+focus on 2251
• @14:30 Taking a break for clouds to pass while NIKA2 meeting ongoing

15:00-21:00 UT Michael + Stefano + Beth

• @15:30 after the NIKA2 meeting. The HWP rotation is off!? How/when did it stop? Stefano starts it again. The data taken for 139-25 will need to be checked to verify if it was active. Grrrrr.
• we are in the clouds. We test the NIKA2 Ar2,1,3 focus values to kill the time while waiting for the clouds to disappear (so says the forecast). We perform few focus sequences (scans 155 to 169). See Table on top of this page.
• @16:20 we have to stop for a while because the clouds are too thick.
• while waiting, Stefano checks the HWP rotation of scans 136 to 141. Indeed the HWP was not rotating. But I'm sure I started it and I checked the Fourier spectrum of the timeline for the 3, 6, ... Hz peaks. Maybe I'm confused? WTF. Sorry. 139-25 needs 1.78h back.
• @17:40 we switch to total power. The tuning of KIDs drifts very quickly, just staring at the sky. It's too foggy even for EMIR. We wait patiently.
• @ 18:15 Frederic has gone to switch off the ventilator. Antenna parked. Still cloudy and tau unstable. Waiting for improved conditions.
• @19:30 we start again the observations. Total power. KIDs lost: 17/10/25
• calib_1scan on Uranus and Betelgeuse (scans 178 and 181)
• 108-25: Betelgeuse close enough to be pointing calibrator, start with science maps
  • G192.9090: 2 reps completed, pointing before 3rd - poor focus, point + focus on Uranus

21:00-03:00 UT Tuan-Anh: The tau value ~ 0.23 at the beginning of the shift and it is increasing. So we continue with total power.

• 108-25 G192.9090 (with Michael): 1 reps completed, point + focus on Uranus
• 108-25 G195.6652: 3 reps completed, point + focus on Uranus
• 108-25 G195.5194: 2 reps completed, pointing on SMA_0539+145
• few calib_1scan on Uranus

Thursday 8th January 2026

03:00-9:00 UT Remi: The opacity was showing large variations so far, but is stabilizing and decreases during the shift (about 0.2), the wind is about 5-7m/s. Box A2-C is still as yesterday. IMBFITS are made with both versions smoothly.

• Finishing science scans for project 108-25
• Pointing on SMA 0725-009 to end project 108-25
• Switch to nikaw-25 for calibration
• Calibration session under good conditions (in particular including focus checks) using 3C 273, 3C 279 and 3C 286. Most other calibration sources are not available.
• Focus on 3C 273 gives: A1:+0.33, A2:-0.63, A3:+0.6. This was done in two steps since the offset are so large. See TAPAS.
• Focus on 3C 279 (brighter but lower elevation) gives: A1:+0.35, A2:-0.65 , A3:+0.59
• Move to 1807+698 for a pointing and start project 197-25
• 2 repetitions on 197-25, first target
• Comment: given the issue with box A2-C, it could be useful to show the footprint of the array not only in Nasmyth but also RA-Dec, for each scan, so that we can optimize the scanning direction (e.g. favor scans in a direction perpendicular to the box C strip)
• Comment: on A3, we observe larger noise for one of the electronic box, as for A2-C but less significant (was already the case in November 25 so most likely already noticed)
• Move to 1807+698 for a pointing.
• 2 repetitions on 197-25, first target

09:00-15:00 UT Beth (+ Stefano)

• We take over from Remi and complete the last repetition of 197-25
• 166-25 one repetition of GC1
• The new make-imbf got stuck on scan 88, Stefano asks AJ to have a look. These scans are big, but not overwhelming (e.g., a beam map is bigger)
• Meanwhile we get away from the Sun and we make a round of calibrations: skydip (scan 93), calb_1scan MWC349 (scan 106), NGC7027 (107), CRL2688 (108)
• During subscans 9, 10, 11 of the Skydip, while moving to the next position, we get tracking errors by the ACU (beeping)
• Switched to NIKA2-pol at 11:40 UT. It took 3 DAQ reboots and one MPPSYNC reboot to bring the HWP rotation to life. Lost KIDs 21/6/34.
• Starting the NIKA2-Pol observations roughly @12:00 UT and set up:

  • Attempt point, focus on 3C286 ahead of first project calib_1scan but too faint, too low alas, full wrap it is

  • Point, focus on 2230+114 whilst 3C454 crosses 100 deg wrap limit. Taumeter records a spike to 0.5 at 12:25.
• @12:40 139-25
  • Start with a calib_1scan, pretty nice view and tau ~0.2
  • SB: re-checked that the HWP is rotating properly, before starting the science scans
  • HH288 2 reps, with calib_1scans an focus checks on 2251+158 and Neptune in between.

15:00-21:00 UT Michael + Beth (+ Stefano)

• continuing on 139-25: two more reps on HH288 (i.e., 4 reps total)
• SB: regularly checked that the HWP rotation is fine
• 17:55 final big unwrap to Uranus for a calib_1scan and over to 128-25
• 128-25: 2 reps of L1482 using Uranus for IP monitoring in between

21:00-03:00 UT Tuan-Anh:

• pointing, focus then focus again on Uranus, calib_1scan 20260108s214.
• 2 reps on NGC2264d with calib_1scan 20260108s221 and 20260108s226.
• pointing, focus on Uranus, calib_1scan 20260109s6.
• 2 rep on NGC2024S3 with calib_1scan 20260109s12 and Alfori.
• pointing, focus on Alfori, calib_1scan 20260109s.

Friday 9th January 2026

03:00-09:00 UT Remi: The opacity was stable/slowly decreasing so far (< 0.2), the wind is about 5-7m/s. We start in polarization mode.

• pointing, focus on 3C 273, and calib_1scan
• pointing, focus on 3C 279, and calib_1scan
• pointing on 3C 276, and calib_1scan
• calib_1scan using 1228+128 from extra_QSO_XPOL_NIKA2.sou
• pointing, focus on 3C 279
• calib_1scan using 1127-145 from extra_QSO_XPOL_NIKA2.sou
• Switch to total power: lost kids 21/7/34
• Pointing on 1807+698
• Start 197-25
• 1 repetition on first target
• The opacity has been slowly rising now and the data quality reduces, but still ok
• Pointing on 1807+698, 2mm beam : beam 17 x 19.5 (focused on A1)
• 1 repetition on first target
• The the data quality is limited (lot of correlated noise residual and stripping): high altitude thin clouds are there indeed but the target is in a region that is ok.
• Pointing on 1807+698, 2mm beam : beam 17.6 x 19.3 (focused on A1)
• 1 repetition on first target
• The the data quality is still limited but possibly improving.
• 1 repetition on first target
• Comment about sensitivity: currently, the first target of 197-25 should have been completed yesterday already. However, while we approximately reach the goal rms at 1mm, we have a rms that is 1.45 higher than expected at 2mm. This is likely due to the issue of A2-C electronic box, due to the delta focus issue, but also due to the fact that observations were carried at lower elevation than required to fill the gap in the schedule. Nevertheless this is very preliminary because the new calibration files are not available yet and this will change for sure, especially at 2mm given the focus issue.
• The data quality quickly degraded at the end of the repetition, i.e. last 2 scans (low altitude clouds coming from Granada + high altitude clouds towards the mountain)
• pointing on 1807+698
• Back to nikaw-25
• We are in the cloud now but at the limit (can see blue sky when looking at zenith). The opacity is rising fast. Let see how it evolves.
• Go to 3C 279, pointing, focus
• @9:00 UT We need to stop because it is wet and windy.

09:00-15:00 UT Beth. I take over with the telescope parked.

• Restarted 10:45 UT - total power - retune, lost KIDs 38/8/43
• Try to get focus on 1757, but low elevation and variable sky conditions although tau nominally ~0.18. Looking good! Let's observe some GC.
• @11:10 166-25
  • 1 rep on GC3 going down to 20deg el limit. In the clouds for last part of last scan
• Retune before starting calibrator scans on MWC349, NGC7027, CRL2688 and a skydip. Lost KIDs 42/9/42.
• calib_1scan on MWC349 (scan 123), NGC7027 (scan 124), CRL2688 (scan 125), and skydip (scan 126). Again alarm at sub-scans 9, 10, 11 of the skydip, just like yesterday.
• @12:50 UT switched to NIKA2-Pol; all fine at first attrmpt. HWP rotating fine. Lost KIDs 26/4/48. We wait for thin, variable clouds to pass and blue sky to return, attempting point/focus now and again.
• @14:00 UT we give up and swap to EMIR, 149-25 tuning
• @14:30 UT the atmosphere is getting wet. We lower the Antenna to El 10 deg and we wait for an improvement.
• @14:45 UT we try to start again but the IF switch box is not working. Kike goes up to reset it.

15:00-21:00 UT Michael

• @16:00 after many attempts, it turns out that E150 ain't working
• @16:00 meanwhile the sky is free again. We switch to NIKA2-Pol for 084-25 (max tau = 0.4). Lost KIDs 15/5/24. HWP rotating regularly.
• 084-25 started the calib_1scan before observing the science targets, but @17:00 UT we have to park the telescope because the wind speed is now above the limit. Sigh

21:00-03:00 UT Tuan-Anh

• telescope parked because of high wind
• @22:00 UT re-start of operations. One hour of XPOL lead by Ioannis, to observe Uranus and characterise the instrumental polarization
• @00:00 UT NIKA2 total power, 108-25,

  • 2 reps on G195.6652 then pointing on SMA_0539+145 [SB: it turns out this target had already been observed the night before, but in the README file the time was marked on another target. Since only 2 reps are requested, 108-25 shall get 1.5h back]

  • 2 reps on G210.1020

Saturday 10th January 2026

03:00-10:30 UT Remi: The opacity show large jumps but the sky is clear and the NIKA2 data are very good (about +/- 2 Jy/beam over the last pointing), the wind is about 5m/s. We are in total power.

• I learn from the operator that an XPOL session is scheduled from 4am to 8am (UT).
• Finishing a science scan on 108-25
• pointing on SMA_0539+145 to finish with 108-25
• Start nikaw-25
• Pointing, focus 3C273
• 3:40 -- we stop and start with XPOL. I go back to bed.
• @8:00 UT back to NIKA2 total power. Lost KIDs 14/5/21.
• go to 1638+398 for pointing and focus. Unlike what xephem shows, this source is too faint for proper focus
• go to 1807+698 for pointing and focus.
• start project 197-25
• run 1 repetition on the second priority target
• 1807+698 for pointing and focus
• run 1 repetition on the second priority target

10:30-15:00 UT Beth:

• 166-25 one rep on GC3; stable sky

• @12:00 homology alarm when pointing MWC349 at El=72 deg; pointing oofset larger than 30 deg in El (negative); Blue Pill restarted; OK again; <5 minutes lost

• calibrators: MWC349 (scan 147), NGC7027 (148), CRL2688 (149), skydip (150)
• usual tracking alarm during the last 3 sub-scans of the skydip
• @12:50 UT we switch to NIKA2-Pol. Lost KIDs 18/6/23. Focus and point on 2251+158, everything looks good
• @13:20 UT start 139-35:
  • 4 reps on HH288. Reference calibrator 2251 as usual at start, then Neptune after 2/4, then Uranus

15:00-21:00 UT Michael + Beth + Stefano

• Beth observes the second two reps of HH288 139-25 up to @17:xx UT and hands over to Michael
• 128-25 start @18:00 UT - 4 reps of L1482
• @19:00 UT tau is ~0.3 but the stability of the sky evaluated in the data (i.e., in our l.o.s.) is very good (+/0 2 Jy/beam @2mm on the timeline of the science scans (!)). Therefore we keep going.
• SB: scan 20260110s212 big spike in the timeline. Cause unknown. Are they talking to us?

21:00-03:00 UT Tuan-Anh

• 084-25: pointing, focus, on Uranus then calib_1scan 20260110s233.
• 2 reps on G138.2957 (source completed - 6 reps in total) with calib_1scan 20260110s243 and 20260110s251
• pointing, focus, on Uranus then calib_1scan 20260111s258
• 2 reps on G139.9091 with calib_1scan 20260111s7 and 3C84 (other qsos were set).
• @2:30 UT switch to NIKA2 total power. Lost KIDs 20/5/35

Sunday 11th January 2026

03:00-09:00 UT Remi

• Tuan-Ahn was observing project 108-25 and we finish the repetition. No Sure if Tuan-Ahn updated the readme: to be checked when he wakes up.
• Pointing on SMA_0725-009 to check the data for 108-25.
• Set project nikaw-25
• set topo high and go to 1641+399 for focus (expect ~4Jy according to 197-25 README). This will avoid doing 2 turn of the telescope compared to if we focus on 3C279.
• Start project 197-25
• Launch 2 repetition on the 2nd priority target
• Pointing on 1807+698. The timelines are a bit strange (all arrays), as if a large part was flagged. Still ok for the pointing and get a map, but weird. Something similar happened on some focus earlier. These are scans 20260111s43 and 20260111s24.
• Launch 2 repetition on the 2nd priority target
• On scan 20260111s56, the issue with strange timelines (jumps?) happened again. This time this is a science scan. See attached image

• Pointing on 1807+698.
• Launch 1 repetition on the 2nd priority target

08:30-15:00 UT Beth + Stefano

• SB takes over a bit earlier because the 197-25 rep is completed. tau~0.4, but sky very stable (peak to peak sky variations in pointing scans +/- 2 Jy/beam @2mm)
• calib on NGC7027 at the Az=60 limit (scan 70), skydip (scan 72)
• 166-25 one rep on GC1

• @9:47 UT the new make-imbf gets stuck on scan 81 (first scan out of two of GC1). Note that on 2026/01/08 the new make-imbf got stuck on the same target and same scan. For the pointing and focus that come after GC1, we waste a huge amount of time because we have to use the old make-fn-imbf again. The new make-imbf is clearly not yet reliable. We cannot switch the old one off any time soon.

• SB tried to produce the imbf with the new system by hand, but it did not work.
• @10:25 UT AJ re-started the make-imb. Thank you for responding so quickly on a Sunday!!!
• SB tries to produce the imbf with the new system by hand, but it still does not work.
• 166-25 one rep on GC2
• @11:45 UT retune - lost KIDs 16/6/36 - and round of scans on calibrators: MWC349 (scan 101), NGC7027 (102), CRL2688 (103)
• 137-25 one rep on L1241
• make-imbf issues?
  • @12:50 UT the new make-imbf seems stuck again. The last scan processed was 107 (created at 12:25 UT). SB tries to manually produce the imbf od scan 108, but it does not work. SB stops the new make-imbf and starts it again. Let's see with scan 109 if this "reboot of the make-imbf" is sufficient to resuscitate it.
  • meanwhile the old make-imbf is producing empty files [Ar2, scans 99 (track), 104 (track), 106 (track), 108 (otf 137-25)]. For track, this is normal. I wonder therefore if scan 108 is interpreted as a "tack" for some unknown reason, althpugh it is an otf of 137-25 L1241.
  • the new make-imbf produces the imbf of the 109 scan regularly. The old make-imbf too. I wonder if the new one was resuscitated by the switch off/on, or if the scan 108 is interpreted as a track by both (and therefore skipped by the new make-imbf and produces as empty file by the old one). Why? Uff.
  • SB reports this episode to the computer group and to the relevant people via email.
• @14:20 UT: Swap to NIKA2-Pol. Very efficient today, good teamwork :D. Lost KIDs 20/5/41.

15:00-21:00 Michael + Stefano

• tau(225)~0.35, very stable sky (+/- 2 Jy/beam peak to peak in pointing timelines at 2 mm)
• 084-25 using 2251+158, Neptune and Uranus as IP calibration sources at regular intervals in between science scans. Taking calib_1scan on both Neptune and 2251+158 when are both available, with the aim to characterize the IP of the science scans with 2251+158 and Neptune (they're at different elevation, for science scans at different elevation) and the intrinsic polarization of 2251+158 with Neptune.
• 084-25 1 rep of S87IRS1
• 084-25 4 reps of IRAS23033

21:00-03:00 Tuan-Anh

• I let the last repetition of 084-25 IRAS23033 finish (see previous shift)
• switch to 015-17 (09:50 UT), pointing, focus on Uranus with calib_1scan 20260111s204.
• 2 reps on NGC2264d with calib_1scan 20260111s211 and 20260112s2.
• pointing, focus on Uranus with calib_1scan 20260112s9.
• 1 rep on NGC2024S3 with calib_1scan 20260112s16 on 3C84.

Monday 12th January 2026

03:00/09:00 Remi Very stable condition, low wind (2m/s), and the opacity is dropping (0.16 at the start). The plan is to do total power beam maps under such conditions.

• Changing to total power. Lost KIDs: 17/4/22
• Go to 3C279, pointing and focus on A2. The source is slightly low (34 deg) but this will improve with time. This is also why we start with A2 that is less sensitive to beam deformation and the amount of air mass.
• Starting beam map for A2 (with option "l": 65"/s azimuth scans, I hope this is fine ; it should as far as I see in the script). Note that due to this option I messed up with Pako and I had to restart it, hopefully everything is ok, checking also with Frederic.

• The wind is slightly increasing but still <5m/s.

• The new imbfits is stuck again; the old one is almost catching up for Ar2 but it is at scan 20260111s180 for Ar1 and Ar3 (we are now observing 20260112s45). This is obviously a problem for focusing on Ar1 and Ar3 for the next beam maps. The production of the individual imbf "by hand" with the AoD or operator account doesn't work.
• Frederic restart the imbfits creator
• We have to wake up Stefano (sorry) and he managed to restart it (see few lines above). Thanks!!!
• Again 3C279, pointing and focus on A1. The source is now at 43 deg elevation
• Starting beam map for A1.
• The wind is increasing: 5 m/s now
• Again 3C279, pointing and focus on A3. The source is now at 46 deg elevation
• Starting beam map for A3.

• The same "stuck subscan" alarms rings for the Ar1 and Ar3 beam maps. Frederic explains that there is a scan length > 25 minutes alarm (designed for EMIR), therefore no worries.

• the new make-imbf gets stuck also at the Ar1 and Ar3 beam maps. It is restarted as for the Ar2 case.
• Track 1807+698, start project 197-25, and pointing
• Launch 2 repetitions on 2nd priority target
• On scan 20260112s68, we again have the jumps/weird timelines. See plots attached. The scans before and after are fine, and the jumps happen during all the scan. All arrays are affected in the same way. Could it be a tuning issue, something else?

• The wind is back to 2 m/s
• Pointing on 1807+698 and focus
• Launch 1 repetition on 2nd priority target

SB about the scans with weird (corrupted) timelines: Some scans show a very weird behavior of the timelines, with the signal jumping and many records being rejected by the PIIC QL-monitor data processing. The problem affects all three NIKA2 arrays simultaneously. And it seems to be happening throughout the whole scan (not just a fraction of it). It happens only on one scan: the previous and next scans are just fine. Therefore one suspect we had was whether there might be some incorrect tuning at the beginning (remember that during the scan no re-tuning is performed). But would it be incorrect for all KIDs? Remi tried to reduce one of them offline with PIIC and the whole scan was rejected. As of 2026/01/12 @8:00 UT we have seen at least 4 cases. Two of them are in 197-25 science scans 20260111s56 (06:49 a.m. UT) and 20260112s68 (06:27 a.m. UT). Other two examples I am aware of: 20260111s49 (05:53 a.m. UT, pointing scan), 20260111s24 (02:53 a.m. UT, focus). Note that the QL does not process big scans (e.g., beam maps or long polarimetry scans), therefore there might be (many) more scans affected by this issue. We don't know what is the cause of this behavior. It does not seem to be related to the sky conditions, because on 20260112 the sky was great, but during the night of 20260111 it was less good. Magnetic fields induced by the telescope motors? Problems in the tuning at the start of the scan? Satellites? Geomagnetic storm due to solar activity? Cosmic rays? Other ideas? -- EMIR Local oscillators ? <CK> SB: Frederic says it's a good idea but they're off since the XPOL session.

@12:00 UT checks in the cabin by SB: a) there is no active WiFi; b) one of the two ladders on top of the NIKA2 cryostat (the one closer to the mirrors and to the NIKA2 window) was touching the cryostat. I moved it enough to allow a 5-7-10 cm gap.

On 2026/01/13 Alessandro suggested that it looks like tuning during the scans. SB notes that this is not a feature of the NIKA2 DAQ, unless someone modified or intervened remotely while we were observing.

On 2026/01/13 also Xavier and Nicolas have quickly analysed the data: their conclusion is that the problem was caused by vibrations. I copy here their message: "Our conclusions are that all electronic boxes are affected. There are no unwanted tuning during the scan except at the beginning as expected. Looking at individual detector raw data: for some Kids, they look perfect. For some others, it is terrible: see in the I,Q plane the large deviations from the circle. This is not possible with photons. Therefore, vibrations are the main culprits. Some kids are more sensitive than others to that. The vibrations are stronger at the beginning of the scan for this scan. We let Alessandro and Martino say whether the PT heads can be guilty or not, otherwise something is shaking the cryostat. The end result is that up to half the kids will be killed in the processing."

SB: Thank you all for your ideas and analysis! Could the culprit really have been the ladder touching the cryostat? Why did it affect only few (random) scans?

09:00-15:00 UT Beth

• @8:30 UT we switch to NIKA2-Pol. Lost KIDs: 20/6/43. HWP rotation started fine at 1st DAQ reboot.
• 126-25
  • IP calibration on 3C279, 3C286 and 3C454, observed in between science repetitions
  • 3 reps (2 x 1.5 rep blocks) on G28.34+0.06
• @12:00 UT Stefano goes to the cabin to check the ladder by the cryostat and the wifi (see above).
• @12:15 UT: 139-25
  • AUGH! Just missed the cutoff for wrap between 3C454 and the science targets by 0.1 deg. We go the long way, so Beth almost points the telescope at the Sun for the second time today.
  • IP calibration on 3C454 (2251+158), Neptune, Uranus (as they rise)

  • 2 reps on HH288 (blocks of 2 reps), let's aim for 6

15:00-21:00 UT Michael and Beth

• Beth finishes up some calib_1scans and runs some ql reductions as the sky seems a little more unstable (but still good enough for now)
• Another 4 reps 139-25 HH288
• 128-25 one rep of L1482 using Uranus as IP calibrator

21:00-03:00 UT Tuan-Anh

• 084-25 1 reps of G139.9091 using Uranus as IP calibrator.
• 22:50 UT: telescope parked because the strong wind.

03:00-09:00 UT Remi

• Telescope parked because the strong wind: no observations
• @8:30 UT the AoD switches off the NIKA2 DAQ. The pool week is over.

Thank you all for your presence at the telescope, the support in the observations and the wonderful time together during this past week. See you next Time. Stefano.