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Daily Reports (2026/01/20-27, NIKA2 run 78, Cryo run 90)

Observers on-site: Carsten Kramer, Mairi Nonhebel, Friedrich Wyrowski, Ping Zhou

Astronomer on Duty: Stefano Berta (on-site)
Pool Manager: Angel Bongiovanni (remote)

Operators: Pedro (day), Sergio (night)

Organization of shifts:
03:00-09:00 LT: Carsten Kramer
09:00-15:00 LT: Friedrich Wyrowski
15:00-21:00 LT: Ping Zhou
21:00-03:00 LT: Mairi Nonhebel

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
  20260120s52-56	Uranus	out	0.96	1.15	yes	started at 1.3 mm; variable sky
  20260121s13-17	3C279	out	0.74	1.01	no	started at 1.0 mm ; Ar1 and Ar3 FWHM only; s13 with vibrations problem (?)
  20260121s18-22	3C279	0.19	out	out	no	started at 0.2 mm; focussed on Array 2
  24-28	3C279	out	0.79	1.1	no	started at 1.5 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
  20260121s23	3C279	0.19	TP	focussed on Array 2. Oszillations in Azimuth.

Tuesday, 20th January 2026

10:30-15:00 LT: Maintenance time.

11:30-13:00 LT: training of the observers "on paper" and consolidation of the shifts.

15:00-17:30 LT: Further training of the observers at the control console.

15:00-21:00 LT: POLAMI 087-21 time with a remote observer.

21:00-03:00 LT: Mairi + Stefano

• parked because of wind
• @23:00 LT we start with NIKA2-Pol. Lost KIDs 14/5/25; spiky taumeter; flying clouds; tau(225)=0.2-0.3.
• after the startup with point/focus/point, we move to 084, calib_1scan on Uranus and pointing on a nearby source. The sky is too variable. We stop for 30 minutes to see if the conditions improve.
• @00:15 LT we start again, the sky cleared up
• 084-25 two reps on G139, using Uranus as IP calibrator (the last scan was cancelled b/c of wind). There is no Uranus calib_1scan after the last scan of the 2nd rep
• pointing and calib1_scan on Uranus. Circular beam, no need to refocus, stable sky. Pointing on nearby source then science scans on G139 resumed.
• Wind picked up during final scans of G139. Wind alarm during final scan. Telescope parked at 1:30 UTC after repetition finished, not possible to take calib1_scan afterwards.

Wednesday, 21st January 2026

03:00-09:00 LT Carsten + Stefano

• parked because of wind
• @3:30 LT Wind dropping steadily. 40km/h. Switching to Total Power to prepare for 3 Beam maps on 3C279. tau225~0.12. Lost KIDs 16/6/21.
• @3:50 LT 1226+023 Pointing, switch to nikaw-25, Focus on Ar2, 2mm stability +-2Jy, Beammap.
• scan 10 was hanging in the QL with wind error (too many records with big tracking deviations)
• scan 13: timelines with supposed vibration problem. We will check later the ladder
• resonance of the antenna (+/- 4 arcsec in Az) during the beam map at 3:15 to 3:40 UT (scan 23). No alarm rang
• the new make-imbf produces correctly the beam map imbf files
• @5:00 LT Stefano and Sergio check the ladder on top of the cryostat: it is touching, although it is fixed to the to the floor. It seems that it can be still moved in the direction of the vertex, because the "screws to the floor seem to be only on that side. It would be better to fix all 4 legs, if possible.
• @5:00 LT 137-25 1 + 2/3 reps on L1241
• @6:45 LT The EHT dress rehearsal team takes over

09:00-15:00 LT (Friedrich) Stefano + Mairi + Carsten

• Friedrich has fever since yesterday evening. We reshuffle the shifts to cover his until he will feel better. Gute Besserung!
• The EHT dress rehearsal continues until 11:30 LT
• @11:30 LT we take the telescope back: EMIR time
• 150-25: tau steadily increasing. Searching for sufficiently bright source for focusing. @12:30LT ~0.35.
• we manage to focus on 2251+158, but after 2 full round trips of the celestial sphere @12:50 LT we give up because the pointing on the source nearby the science target is terrible. At least we tried.
• @12:50 LT the telescope is parked because of bad sky

15:00-21:00 LT Ping

• Telescope parked: snow, frozen rain and wind.

21:00-03:00 LT Mairi

• Telescope parked: snow, frozen rain and wind.

Thursday, 22nd January 2026

03:00-09:00 LT Carsten

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09:00-15:00 LT Friedrich

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15:00-21:00 LT Ping

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21:00-03:00 LT Mairi

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Friday, 23rd January 2026

03:00-09:00 LT Carsten

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09:00-15:00 LT Friedrich

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15:00-21:00 LT Ping

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21:00-03:00 LT Mairi

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Saturday, 24th January 2026

03:00-09:00 LT Carsten

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09:00-15:00 LT Friedrich

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15:00-21:00 LT Ping

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21:00-03:00 LT Mairi

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Sunday, 25th January 2026

03:00-09:00 LT Carsten

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09:00-15:00 LT Friedrich

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15:00-21:00 LT Ping

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21:00-03:00 LT Mairi

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Monday, 26th January 2026

03:00-09:00 LT Carsten

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09:00-15:00 LT Friedrich

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15:00-21:00 LT Ping

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21:00-03:00 LT Mairi

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Tuesday, 27th January 2026

03:00-09:00 LT Carsten

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