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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 in general along the minor axis of the fit, the 1-component Gaussian fit is rounder than the main beam).
• 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: