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NIKA2 Re-Commissioning (2nd. part)

June 10th-12th + 16th-18th, 2025

NIKA2 run 73, Cryo run 85

Infos about the PIIC DAFs for the PIIC monitor

SB has produced some temporary DAFs to be used for run 73 Ar2. They are already copied at Pico.

The idea is to use two different sets of DAFs for Ar1+3 and for Ar2:

• for Ar1 and Ar3, use the DAFs that were produced with the run 72 data. These DAFs work with the new Arrays 1 and 3, but their reference KID is not the central one (because of the bix C issue), and therefore they's a bit of an offset.
• for Ar2, use the older DAFs (run 68). The SWEEP has not changed since then. These DAFs do include the correct (central) reference KID. Use these for pointing, such that the data will all be properly centered.

I cannot mix the two sets of DAFs, because Ar1 and Ar3 use Ar2 as reference and were built with the non-centra reference KID.

As soon as we have beam maps, I will build (temporary) DAFs for all three arrays, referred to the central KID, and we'll be fine.

Ho to proceed in practice:

• Ar2
  • open a terminal, go to the QL directory
  • gagpiic
  • export MOPSIC_DAFS=/local/users/flexible/reduce/dafs_bck/dafs_local_tmp_run73_ar2
  • start the Ar2 monitor (pf)
  • repeat in another terminal for the Ar2 monitor (m)
• Ar1 and Ar3
  • open a new terminal, go to the QL directory
  • gagpiic

  • echo $MOPSIC_DAFS -> check that it says /sw/gildas/mopsic/dafs

  • if not, then set it to that directory
  • proceed normally with the Ar1 and Ar3 monitors
• if Ar2 does not work, please let SB know, and meanwhile use the standard DAFs (i.e. the same as for Ar1 and Ar3)

At this point, use Ar2 for pointing, such that all data are well centered. As soon as there's a decent beam map available, SB will produce new (maybe temporary) DAFs for all three Arrays, referred to the good old (central) reference KID and will install them at Pico, to be used with the next observations.

ADDITIONAL NOTE (2025/06/10 @22:55): using this double setup, you will see an offset betwween Ar2 and Ar13. It is on purpose. Please ignore it and use Ar2 for pointing/focus, until new DAFs with the central as reference will be produced for all three arrays.

Tuesday, June 10th, 2025

Mónica, Ioannis, Dave, Angel at the telescope. Starting DAQ at the beginning of the maintenance slot.

@11:00: All amplifiers are switched on. T_MC = 0.173 K. Noise traces at this time (ar2, ar1, ar3) are given below.

Traces of ar2 look qualitatively better than those in force during the campaign of March (for a comparison, see the Daily Report of Sunday, March 23rd, 2025 at https://publicwiki.iram.es/DailyReportsNika2Run72).

@15:30: Dave, Mónica, Angel. Cloudy. Rain intervals. Trying to catch a sky hole for a decent resonance work. Configuring NIKA2 at Rx cabin. Restarting DAQ. Impossible to have a reasonably good tuning with the current weather conditions. Waiting for a while.

@17:00: Still being unstable. Taking advantage for testing mppsync/server & HWP. It was necessary to restart the Arduino server. Check: OK.

@18:30: We tried our best for getting good resonances under (very) poor conditions. With 17/6/110 bad KIDS in a1/a2/a3, we tried a quick & dirty (specially the latter) pointing on Mars when wind speed dropped a bit. The good news: the QL-reduction indicates that the amplifier replacement has been successful. Congratulations!

@20:28 Weather still unstable. We did a pointing and see a big offset between a2 and a1/a3 so we changed to the latest DAF's for all arrays. After that there is not offset anymore. We continued with pointing and focus.

@21:00 Stopped. light rain.

SB @22:55 LT: the offset between Ar2 (special DAFs, run 68, see above) and Ar13 (run 72 DAFs) is normal because the Ar2 is referred to the central KID while the Ar13 are not. So basically this offset is on purpose. It will disappear once I produce the new DAFs with new beam maps. Please keep using the run 68 DAFs for Ar2 (special instructions above), and use Ar2 for pointing/focus, ignoring Ar13, so that all data are referred to the central KID and I can produce the new DAFs for Ar13 with the proper reference KID. Otherwise everything will be shifted and we will need to re-do it once again. Thanks.

Wednesday, June 11th, 2025

@00:15: Rolling back to the run 68 DAFs for Ar2 in PIIC. Still windy. Opacity about 0.7 and rising. Telescope parked.

@02:15: Weakly-polarized (<1%) and polarized (>1%) sources from SMA-Pol added by Ioannis to the current commissioning catalogues (see /pako/202503 at t22). It's raining again. Wind peak speed >15 m/s.

@04:00: Stormy weather.

@09:00: Opacity going down (tau_225 ~ 0.9), max. wind speed >18 m/s.

@16:00: Wind goes down and we try to start the antenna.

@16:20: wind speed below 10 m/s and Tau ~ 0.5. We start the acquisition with better conditions than yesterday. Bad kids 10, 6, and 90 in ar1, ar2 and ar3 respectively. Continue with pointing, focus in Mars. The first sequences of focus show that the beam is distorted (a bit elliptical FWHM ~ 20" x upt to 25"). Mars's size is 5.3". We expect the antenna behaves better after the sunset.

@17:40 After several focus sequences specially the last one (scans 23 to 29) the peak to peak variations were from 15 to 30 Jy/beam at 2mm. Atmosphere is unstable. So we will wait for better conditions.

@17:45 SB: Hi! Thanks for starting the observations. I've taken a look to the PIIC monitor plots. Yep, I agree it's better to wait a bit. Is the homology fine, and the table in "level attente"? Thanks. Cheers. I'll check later tonight again. Monica-Ioannis: the homology is fine (we have not get any alarm) and the option is set to level_attente.

@19:50 Starting observations again, tau is decreasing. Checking pointing and focus in Mars. The pointing sequences show that the beam is still a bit elongated (scan 50 FWHM ~ 19.1" x 24.6"). We will try later in 30 min.

@21:00: Acquisition restart to recover more dead pixels. Results now look much better with 9/3/45 bad kids for ar1/2/3. Pointing and focus on Mars to check beam and conditions.

@21:28: Wind increased (some alarms for high gusts). Antenna parked.

Thursday, June 12th, 2025

@00:30: Wind speed dropped a bit on average, last gusts: 13-20 m/s; tau_225 ~ 0.35.

@02:10: Gusts about 10 m/s. Wind blowing from South direction. DAQ restarted, 9/6/40 bad kids for ar1/2/3. No planets/bright QSOs at ~40 < El. < 75 deg. right now for a beam map.

• First pointing 1741-038 (Az. ~175). Moderately good tracking; one focus scan lost due to high tracking deviations (38.6%). No focus fitting. P2P variations of timelines: 10-20 Jy/beam (2 mm).
• Moving to 3C286 (Az. ~283). First pointing and one focus scan lost due to tracking deviations (25-29%). Guess focus correction: 1.8 mm
• Moving the telescope backing to the wind: 1928+738 (Az. ~370). Tracking deviations remained below 20%. Best focus: 1.4 mm.; FWHM 17.4" x 19" (2mm) after pointing. Estimated MB flux (2 mm): 1.6 mJy/beam. Looks more stable in the l.o.s.
• One round on G2 field launched before reaching El. 30 deg. Motor torque and wind alarms activated almost simultaneously when the third scan (out of four) of the round was finishing. Despite this, no significant tracking deviations appear in the first two scans gathered. Telescope parked at 03:40 (LT).

@04:00: The upward trend in wind speed is confirmed. Waiting for better conditions.

@10:00: Wind mean speed has continued to increase since early morning.

@11:30: We find a small window with a bit lower wind speed and decide to start the system in case we can take some data. Tried on Uranus and 3C84 but wind is fighting back hard. Many scans are lost due to tracking errors, 25%, 35% 45% ... Shortly before the end of the T21-25 slot this week, we go back to Uranus and we get a pointing. Focus is again not possible due to lots of tracking errors (in elevation. in azimuth tracking looks fine). In the last 20 mins we made the "executive decision" to start a beam map, even if the conditions are far from ideal (manual focus correction, wind on the limit, similar elevation and relatively close to the Sun - 23 degrees ...) but maybe it can be (marginally) useful, at least for a "crude" analysis (e.g. matching the ar1/3 and ar2 geometries etc.).

SB @18:20 LT: Thank you for tese heroic days and the final attempt. The beam map is scan 20250612s43. Results of a quick analysis of this beam map: the quality of the beam map (sky, telescope, focus, etc.) is unfortunately not good enough for making new (preliminary) Ar1 and Ar3 DAFs. Below you see the classic FOV beam-map figure. Ar3 is much worse than Ar1 likely because the best focus difference that affects it. Nevertheless, also Ar1 is unusable.