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Daily reports, NIKA2 pool week #4, Winter 2024-25 semester

First week of the NIKA2 run 71 (Cryo run 83).

This time, 8 days, starting on Monday, instead of 7 starting on Tuesday. Change of plans: we will go up to the Observatory on Tuesday as usual, hence 7 days.

Observers on-site: Philippe André, Helena Mazurek, Chiara Mininni, Ioannis Myserlis (AoD), Monica Rodriguez, Ste B. (AoD)

Operators: Kike and Frederic

NOTE by SB: if possible, please take some total power beam maps (Uranus at best); and some pol beam maps on Uranus too.

Note by CK: During the holography run last week, several panel frames of the primary have been adjusted. Uranus observations were conducted on 10/11 Feb with EMIR. Telescope efficiencies may well have changed (slightly improved).

Feb 10th, Monday

The plan has changed. Spindle nr 6 is being replaced today and the operation will take until tomorrow, end of maintenance. Therefore the observations will start tomorrow.

Update on the Spindles work: yesterday the wind was rising, hence there's not been time to change the spindle motor. All electric connectors have been checked and few were found loose and have been fixed. The sub-reflector was mounted back in place. Few hours of EMIR observations were carried out as a test. During these few hours, three Spindle errors occurred.

Feb 11th, Tuesday

Chiara, Helena, Ioannis, Philippe, Stefano and maaaany others arrived to the telescope.

During maintenance, we prepare the NIKA2 setup: we open the VNC, start XEphem, start the PIIC monitors, start the make-imbfits (old). We test the rotation of the HWP: all works fine.

16:00-21:00 LT: Chiara + Helena + Stefano: wind, the telescope is parked. Training the new observers about how to read the PIIC monitor, fill Tapas, fill the Daily report, and everything they've ever wanted to know about what we are going to do when the wind will give us a break.

21:00-03:00 LT: Helena + Stefano; wind and snow -> telescope parked

Feb 12th, Wednesday

03:00-09:00 LT: Ioannis; I start the observed around 5 a.m. LT. Progress of the morning:

• setting all up and waiting for the de-icing to switch off
• NIKA2 tuning fine with only 25/3/30 bad KIDs
• pointing and focus on 1226+023. conditions still a bit unstable (atmospheric variations at +/- 10 Jy/beam)
• after a while conditions become acceptable and start with projects
• 189-24, one repetition of source CTRS27

• 07:30 UT: SB: The new make imbf is writing data in a new directory /imbfits, but we don't have permission to read it! GRRRRRR. Hence since the start at 04:00 UT, we are using the imbf produced by the old make-imbf. So far it has been ok, but now we are losing time like in the "good old days". This should not happen. If the system/setup is changed, it should work properly. We write to the IT group to fix this issue.

• 07:40 UT: we switch to NIKA-Pol. SB realizes that the leveling of the cryostat was not on level: attente. Be careful with the data taken until now.

• 08:00 UT: While waiting for the data access to be fixed we decide to copy by hand the new scans produced by the new make-imbf in the directory that was used until last time. It is surely faster than waiting for the old make-imbf to write the files. We now have three versions/repositories.
• 08:20 UT: we now have access to the new data directory.

09:00-16:15 LT: Philippe + Chiara and Helena from 15:00 on.

• after initiating NIKA2-Pol, we do pointing and focus on 2200+420 (BL-Lac), as well as calib_1scan (20250212s44)
• 157-24, one repetition of Sgr-B2
• calib_1scan on BL-Lac (2200+420)
• 145-24, one repetition of G16.59, followed by calib_1scan on 3C454 (2251+158)
• 145-24 notes: scan 60 was cancelled for a spindle error (17 minutes lost; this scan does not appear in Tapas; we don't know why, maybe the Antenna-imbf is missing?); also scan 64 was affected by a spindle error and was interrupted (5 minutes lost, it is recorded in Tapas).
• calibrations (MWC349, NGC7027, CRL2688)
• 135-24, one repetition of G75.78 (we had nine spindle/homology errors; but, luckily, only 15 minutes of science scans lost in total)

16:15-22:00 LT: Ioannis + Chiara: special observations, under project T14-24, using a quarter wave plate (QWP) in front of the NIKA2 rotating HWP. This experiment allows to detect circular polarization with NIKA2! It is combined with X-POL observations of the same targets. Polarimetric SMA 1mm observations were also carried out this morning / last night (within the SMAPOL program).

• observation of six targets with the standard NIKA2-Pol: Uranus, 2251+158, 2200+420, 0319+413, Crab and Jupiter
• installation of the QWP at 0 deg orientation, in front of the HWP
• observation of four targets with the QWP at 0 deg (getting short on time, so couldn't observe all six): Uranus, 2251+158, 2200+420, 0319+413
• rotation of the QWP to 45 deg and observation of the same four targets
• observations with X-POL of the three targets. 2251+158 was already at too low elevation.
• removal of the QWP

It's not the full set of observations we would like to take (six sources, four QWP orientations) but should be fine for a first, "proof of concept" test. It will be a challenging but interesting data reduction. It would be nice if we manage to do one XPOL observation on 2251+158 within the next days (maybe also 2200+420, which was observed at very low elevation) to have four targets instead of three to compare their NIKA2 CP against XPOL.

22:00-03:00 LT: Helena + Stefano

• we start NIKA2 again, in total power; lost KIDs: 24/2/37
• Uranus calib_1scan
• 113-24, 3 maps of Orion-B (2 spindle errors; 4 scans cancelled, 16 minutes lost in scans).
• skydip (scan s202)
• 114-24, one repetition of maps 1, 2 and 3. T Elevation is very low, but we have the precise recommendation to keep observing (see the minutes of this afternoon's NIKA2 teleconf.)

Between 12/2 @5:00 a.m. and 13/2 @03:00 a.m. (LT), we had a dozen spindle/homology errors, totaling at least 21 cancelled scans. SB will not continue to keep track of each single lost scan every day. It was only for today. See Tapas for the next days. The total time lost in science scans, today was:

• 145-24: 22 minutes
• 135-24: 15 minutes
• 113-24: 16 minutes

Feb 13th, Thursday

03:00-06:00 LT: Stefano. I continue the total power observations

• @2:30 UT tau(225) is degrading rapidly and now is ~0.4; stability is still +/- 2 Jy/beam. Only 114-24 (see previous shift; current El=22 deg, hence tau(El)=0.4*sec(90-22)>1) and 189-24 (SZ, tau<0.12-0.25) are available now. I take a break and observe M8182 (preparation of re-commissioning, as agreed last week) for ~one hour, waiting to see if the sky stabilizes/improves.

• These scans were observed in Jan 2024 to test the new servo system (i.e. before the new paint); we need some scans after the new painting and before the NIKA2 upgrade, to be compared to those that will be taken during the recommissioning after the NIKA2 upgrade and disentangle the improvements due to the new paint and to the NIKA2 upgrade.

06:00-09:00 LT: Ioannis. Continue with NIKA2 total power

• 114-24, one repetition of Ceph_1 and Ceph_2.
• skydip (20250213s51) - done by mistake in project account (114-24)

09:00-15:00 LT: Philippe. Clear sky; Opacity ~ 0.3-0.35, but very stable sky +/- 1 Jy/beam @ 2mm

• 114-24 continues. one more repetition of Ceph 1 and Ceph 2, two repetitions of Ceph_3 . Lots of Spindle errors: basically every second science scan needs to be cancelled.
• calibrations on MWC349 (20250213s85) and NGC7027 (20250213s86)

15:00-21:00 LT: Chiara + Stefano. The NIKA2 total power observations continue.

• 114-24 a go-go
• calibrations on Uranus (scans 20250213s111 and s120) + skydip (s112)

SB counts how much time has been lost in science scans of 114-24 cancelled because of spindle/homology errors (+ other related scans used to recover the correct homology). When we started, 114-24 had 7.01 hours of observations done. Now @18:05 UT it has 17.89 hours observed. The following scans have been cancelled because of spindle errors and I mark how much time they wasted: 20250213s46 (8.8 min), s53 (2.2), s54 (4.2), s55 (0.3), s59 (24.2), s60 (25.3) s61 (3.7), s63 (10.9), s64 (2.7), s65 (0.3), s89 (7.6), s94 (14.2), s107 (2.9) s123 (20.0). Up to now, the total time wasted is 127.4 min, i.e. (127.4/60)/(17.89-7.01)=19.5% of the 114-24 time observed since we started!.

21:00-03:00 LT: Helena + Stefano. Continue with NIKA2 total power. Tau ~ 0.25

• beammap 99 a on Uranus (scan 149, Spindle error); scan 151 YEAH! Scan 154 calib_1scan
• 113-24, 3 maps of Orion-B
• NOTES about 113-24: scans nr 157 (25 minutes) cancelled because of spindle errors.

• 114-24 one rep of maps 1 & 2; two reps of map 3; all maps now have 9 reps; total allocated time exhausted, including the recuperation of the time lost to spindle errors (see above). DONE!

Feb 14th, Friday

03:00-09:00 LT: Ioannis. Continue with NIKA2 total power

• pointing and focus on 1641+399. Good beam (17x17.9 arcsec @ 2mm) and stability (< +/- 1 Jy/beam @ 2mm)

• 189-24, 3 repetitions of CTRS27 and project completed. DONE! (however scan interruptions by 6 spindle errors prolonged the duration of observations to complete the repetitions)

09:00-15:00 LT: Philippe. Change to NIKA-Pol

• 2200+420 (BL Lac) for pointing, focus and calib_1scan (20250214s52). Good beam (17x17.9 arcsec @ 2mm) and stability (< +/- 1 Jy/beam @ 2mm)

• 145-24, 1 repetitions of G16.59 and project completed. DONE!
• B-FUN (015-17), 3 repetitions of DR21OH; tau225 remained at ~ 0.2 and sky stability better than +/- 2 Jy/beam

15:00-21:00 LT: Chiara (+ Stefano). Continue NIKA2-Pol

• calibrations of MWC349 (scan s98), NGC7027 (s99), Uranus (s101)
• 135-24, one repetition of G75.78; the instrumental polarization is monitored with Uranus (before and after)
• 166-24, five repetitions of Cas-A; the instrumental polarization is monitored with Uranus (before), Neptune (in between), and Uranus again (between and after)

21:00-03:00 LT: Helena (+ Stefano + Monica). NIKA2-Pol continues

• Uranus beam map polarimetry 95 (scan s170), calib_1scan (s171)
• 136-24, 2.25 repetitions of L1482; the instrumental polarization is monitored at first with Uranus and later with QSOs and Mars
• polarimetry beam map on 3C286 (scan 20250215s14)
• @ 01:30 UT we switch to total power; lost kids 13/2/37

Feb 15th, Saturday

03:00-09:00 LT: Stefano + Monica. NIKA2-Pol continues

• total power beam map on 3C273 (scan s22)
• pre-recommissioning M8182 scans
• @04:45 UT the mrt-lx7 machine is completely frozen. The observations are still running in the VNC, so we access them via the AoD's laptop.
• @05:10 UT hard reboot of mrt-lx7 and we re-open all VNC sessions there.
• 135-24, one repetition of G75.78; the instrumental polarization is monitored with 3C273. This is the last of all repetitions requested. Although still 0.83 hours are left, we consider this project DONE!
• 134-24 start.

SB @6:30 UT: we had only a couple of spindle errors in the last ~24 hours. I have the feeling that the higher outside temperature (T was always [well] above zero Celsius, during the last day/night) might be related to the better behaviour of the spindle(s).

09:00-15:00 LT: Philippe. NIKA2-Pol observations continue for a couple of hours, and the sky conditions degrade too much for polarimetry and we switch to total power.

• 134-24, three repetitions of 104316

• @~10 UT: switch to total power tau@225 ~ 0.25 rising and spiky ; Stability between +/- 2 Jy/beam and +/- 2Jy/beam; high-altitude clouds --> Conditions are at best marginal for polarimetry

• Taking advantage of the sky conditions too poor for polarimetry, and with the approval from the 30m scheduler (CK), we continue observing 114-24. This project has already reached 115% of the allocated time, by 7 repetitions were observed at low elevation (< 23 deg) and only 9/12 repetitions have been completed per map (3 maps in total). We now aim at completing all 12 repetitions.

• SB @12:40 UT: stability +/-2 Jy/beam, tau(225)=0.3. Maybe more time could have been dedicated to 134-24 this morning: the sky is partially covered, but both stability and tau are still decent. The afternoon predictions foresee a further degrade of the sky conditions. EMIR will be used when they will not be suitable for NIKA2 anymore. We will proceed with 134-24 and other Open Time projects when the conditions will improve again, likely on Monday morning.

15:00-21:00 LT: Chiara + Ioannis from 16:30. Still total power

• SB @15:00: tau=0.3, stability still +/-2 Jy/beam. I should start drinking coffee and stop sleeping, but after only 3h of sleep in the last 40h, I kinda needed it.

• calibrations on MWC349 (s113), NGC7027 (s114) CRL2688 (s115)

• the sky is patchy (blue/white); CasA is North, where it's bluish; West is grey; test pointing @14:30 UT on 2251+158 (SW): tau(225)=0.27, stability +/- 1.5 Jy/beam at 2mm peak to peak (Az subscan) -> NIKA2-pol we come!

• 166-24, 1.5 repetitions of CasA; monitoring the instr. pol with Neptune (and 3C454 too)
• @ 15:21 UT: tau225 is oscillating a lot, but stability is still +/- 2 Jy/beam in the CasA direction
• @ 16:30 we give up hope and we switch to EMIR. At least we tried
• @ 16:30 - 17:30 switched to EMIR, but did not start observation. The mrt-lx6 machine is frozen, similarly to what happened last night to mrt-lx7. But the situation is more critical now, because we don't have control of the antenna. The control system of the telescope needs rebooting.
• @ 17:30 - 18:15 Ioannis: still technical problems with computer system

• SB @ 19:15 UT: still recovering

21:00-03:00 LT. Helena + Monica. The telescope is back online at ~20:30 UT. It is EMIR time! The wind is rising too.

• 143-24, source NGC 1977, 6 repetitions of the maps, updated them in the table (note: README file is confusing)

• 186-24, source J1244+5009, observed all required scans; source J1449+4941 started observing but scans were not saved --> Frederique fixed it, finished observing all the scans

Feb 16th, Sunday

03:00-09:00 LT. Monica + Helena. We continue with EMIR. Opacity is still high (~ 0.5) and variable.

• 186-24, sources J0850+4036 and J1131+4728
• 126-24 source HMM1

09:00-15:00 LT. Philippe. We continue with EMIR. Only partly cloudy but opacity is still high (~ 0.35) and variable.

• At the end of the integration on HMM1 for 126-24 (~09:10 LT), we wanted to switch to a POLAMI session (Ioannis), but had a technical problem with the BAC5 computer in the receiver cabin. In the end, BAC5 needed to be rebooted (lost ~ 0.5 hr).

• T14-24 session by Ioannis. IM: Did some complementary measurements with XPOL for the CP project of NIKA2. Measured a couple of sources that were missed on Wednesday because there were setting. These measurements will be very useful for the comparison of CP (and LP) with NIKA2.

• 127-24: Starting at 12:20 LT with line setup1, nominally using both E090 and E150, but E150 is not available this week

  • Observed 4 x setup1-otf-psw-lambda-1 and 4 x setup1-otf-psw-beta-1 (including 2 x lambda and 2 x beta at 12 < El < 20 deg) Observing a -4deg Dec source down to 12deg elevation does not make much sense. Mountains may enter into the beam and airmass is really high. The usual lower elevation limit is ca. 20deg. If there is a lack of pool projects/sources then please contact AoD, pool manager, science coordinator, or station manager. CK

• 126-24: Starting at 14:30 LT

15:00-21:00 LT: Chiara + Helena. EMIR observations continue.

• 126-24, source L1521-E finished
• 143-24, source NGC1977
• 1 Spindle error at 17:30 UT after 2 days without any
• 19:15 UT: we switch to NIKA2 total power; tau(225)~0.27
• calibration on Uranus (s286) and ALFORI (s289)

21:00-03:00 LT: Helena (+ Chiara + Monica). NIKA2 total power. Stability below 1 Jy/beam, tau relatively stable at 0.25.

• 113-24,4 maps done, project is finished! <applause>

• @skydip, calib_1scan on Uranus (s306) and Mars (s312)
• pre-recommissioning of M8182 (0,5 rep)
• @beammap1scan99sub.pako a on 3C273 (s14); spindle error (20 minutes lost), relaunching again (s16)

Feb 17th, Monday

03:00-09:00 LT: Monica + Helena + Stefano. NIKA2 total power

• calib_1scan on Mars
• 2,5 reps of M8182 1 pre-recommissioning M8182 (plus one cancelled b/c of Spindle error - 30 minutes lost)
• skydip
• @5:30 UT we switch to NIKA2-Pol
• source 3C273 calib_1scan (40)
• 134-24, science source 126348 completed!

0900-15:00 LT: Philippe Good weather/stability tau225~0.22-0.29 NIKA2-Pol

• 134-24 Two repetitions on 103459 with polarization calibration on BL Lac
• 015-17 (B-FUN) DR21OH: Two repetitions before transit + Two repetitions after transit with polarization calibration on BL Lac
• Calibrations (calib_1scan) on NGC7027 (s103) and MWC349 (s111)

15:00-21:00 LT: Chiara

• Calibrations (calib_1scan) on CRL2688 (s136)
• 166-24, 4.5 reps of Cas-A
• @ 18:10 the sky is getting grey, tau(225)~0.25, but the stability jumped up to 8 Jy/beam peak to peak at 2mm (Az subscan). Therefore @18:30 we switch to NIKA2 total power. We will wait a bit, monitoring the stability, ans we see if keeping NIKA2 or switch to EMIR. The wind starts also to rise. Sigh.
• the "linear" fit (in log space) of the taumeter data was off since 16:40 UT. Now PIIC realised it and complained that the tau-225 array in the imbf files is empty (table 10 of the imbfits). Frederic restarts the taumeter and all works fine again.

15:00-21:00 LT: Helena

• @ 20:05 UT wind above 20, antenna parked

• @ 22:00 UT we resume the observations as the wind has calmed down, very good tau(225) < 0.2

Feb 18th, Tuesday