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Daily Reports

2024 Feb. 20th, Tuesday

Ioannis, Kaiyi, Hervé, Philippe, and Ste B. arrived at the telescope.

Maintenance: the telescope and NIKA2 are healthy. The HWP has been tested and rotates correctly. All is ready for a great week

16:00-20:00; Angel, Stefano, Ioannis, Hervé, Kaiyi: Tuning after maintenance was very good (bad kids 13/2/16). It was done at high elevation of ~70 deg. Then we did pointing and focus on the quasar 0316+413. The beam size for several pointings remained ~ 17.7 x 18.5" at 2mm. The small ellipticity seemed to remain also after focus corrections. Atmospheric stability was ~ 2-5 Jy/beam for the 2mm data. Around 17:00 we started a training session of NIKA2 observations for Hervé and Kaiyi. Then started observations of project 150-23 and did also a skydip [scan 20240220s82]. After initial pointing, we loaded an OTF map on source "id307" but we had to stop the observations after only one scan was completed (around 19:30) because the wind velocity exceeded the limit (reached up to ~ 14 m/s). Tracking deterioration was also visible up to the point that we stopped.

Note that scan 20240220s82 was not processed and a "synchronization problem" message appeared on the PIIC ql monitor screen. The file size kept increasing for a long duration and I had to stop the imbfits creation process. After consulting with Stefano, we realized that this might have been caused because the telescope was slewing for a long time to the source position when a "pointing" command was issued. A "track" command should have been used instead to avoid this large imbfits file creation.

Input by Hervé: The shift was mostly dedicated to the observation of source id307 of the project 150-23. We also performed a 6 minutes skydip [20240220s82]. The beam was checked two times in a nearby target (source 0716+714), yielding a quite stable beam of ~ 17.5*19 arcsec. Observations started with good conditions (stability characterised by RMS of about +/- 1-2 Jy). Unfortunately, the shift closed at about 19:00 due to wind ~14 m.s-1. In the end, only the first scan (1/4) of the first of two rounds that were scheduled in the observation script was performed.

20:00-02:00; Philippe and Ioannis: Wind drops below limit around 00:30 and we start with a tuning (bad kids 14/2/14). Sky stability very good with rms ~ 1-2 Jy/beam @ 2mm. Encountered problem with synchronization of data files. Restarted several systems (data collector, imbfits file creation, acquisition sw and retuning, ACU communication system etc.) but didn't help. Then we restarted taumeter system that was stopped for a while and files are now properly created and processed again.

Wind... imagine strange noises... sigh.

2024 Feb. 21st, Wednesday

02:00-08:00; Stefano: after pointing and focus performed in nikaw-23, I switch on the good old "Telescope Chillin'" playlist to help me wake up and I start observing for 153-23. Very low wind (~3 m/s avg), very low tau (<0.1 on the 225 taumeter), very stable sky (<+/-0.5 Jy along the timeline of a pointing (first two subscans), i.e. scanning in Az).

• 2 repetitions of AR2623 (El~49-52 deg) before culmination
• pointing/focus check, rather important sidelobes (~10%) that influence the Gaussian fit of the main beam (MB) to be up to FWHM~17x19 arcsec at 2mm (note that it's a fit mislead by the sidelobes, i.e. not really MB only; as the most prominent sidelobes (the Mickey Mouse ears) are for focused maps along the minor axis of the fit, the 1-component Gaussian fit is rounder than the main beam; also important: the 2mm NIKA2 beam does not say much about the quality of the 1mm beams).
• 2x0.15 repetition of AR2747 at high elevation (El~74-77 deg) before culmination. See comments on Tapas.
• 2 repetitions of AR2623 after culmination
• pointing/focus check
• 2 repetitions of AR2747 after culmination
• pointing/focus check
• 1 last repetition of AR2747

Note the large pointing offsets (~11 ~7 arcsec) close to Az~180 deg (i.e. South) and El~55 deg.

Good morning :)

08:00-14:00; Kaiyi: The weather condition was good, with tau_225GHz~0.1. After adjusting the pointing and focus (stability with in +/- 0.5 Jy/beam), we did flux calibration with MWC349 (Scan No. 82), NGC7027 (Scan No.83) and CRL2688 (Scan No. 84), following with skydip (Scan No. 85). We observed the project 106-23 with its source: 20243+3853, but only finished 1 round of the scan. And we stopped and changed to other project because the elevation of the targets in this project were too high. We observed the project 015-17. Moving to Mars to try some polarimetry. The observation is done by the PI of this project. During the observation, the 2200+420 point source is selected for calibration (calib_1scan, Scan No.111, but took a very long time to write the imb.fits ~ 0.5 hr). Started the scan of DR21OH.

Philippe's input on B-FUN observations: Clear sky, low opacity (tau225 ~ 0.15), good to very good stability +/- 1-5 Jy/beam @ 2mm. Started with NIKA2-Pol around 11am (UT) [IM: Good tuning with HWP, bad kids 27/2/34]. Took 1 calib_1scan on Mars (s107), 2 calib_1scans on MWC349 (s113 and s118), 1 calib_1scan_high_el (@ 25"/sec; s111) + 1 calib_1scan (@ 40"/sec; s111) on BL Lac=2200+420, and observed 1sequence of 3 maps on DR21OH for the BFUN project (s114-116). While doing so, experienced big overheads due to the very long time needed by the system to create the imbfits files for, e.g. pointing/focus scans after long science maps and/or long slews.

14:00-20:00; Hervé: The shift started with a switch from polarimetry calibrations previously performed toward MWC349 and 2200+420 (project 015-17) to photometry observations with NIKA2. Unfortunately and despite a constantly low atmosphere opacity (tau < 0.2), NIKA2 observations turned out to be precluded by an irregular beam shape, likely affected by fast variations of the atmosphere temperature [IM: thermal instabilities of the dish]. Specifically, the beam looked asymmetric with a fwhm of 17.91*22.3 arcsec, even toward a bright source (0316+413) that we selected opposite to the Sun. The situation was similar or slightly worse toward Uranus, with a very irregular beam shape on both the NIKA2 bands. In the middle of the shift and during the sunset (17.00-19.00), we decided to wait for stabilization of the atmosphere temperature, and to switch from NIKA2 observations to a 2 hour run of EMIR observations of the source W3-IRS5 of the EMIR backup project 104-23.

No caption needed:

20:00-02:00; Philippe: back to NIKA2. Lost KIDs 28/2/34. ...

2024 Feb. 22nd, Thursday

02:00-08:00; Stefano: I take over and continue to observe the 150-23 project:

• pointing/focus check

• last repetition of id307 (8.3/8 rep. in total -> completed). tau(225)~0.2 much better than predicted. Sky stability within +/- 5 Jy/beam, as measured in pointing subscans in Az only. Scan nr. 2 of 8 experienced an isolated wind episode with speed up to 12 m/s

• pointing/focus check
• 2 repetitions of id386 (now the total is 5/8), tau(225) between 0.2 and 0.3, no wind, pointing/focus check between the two repetitions

I close the night with a skydip (scan 20240222s42) and I start some calibrations on the fantastic trio MWC349, NGC7027 and CRL2688 for the morning shift to complete.

08:00-14:00; Kaiyi: ...