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April, 18th (Tuesday)
Start of the official run.
First things first: verification of the alignment (since it changed for an unknown reason between run 8 and 9!)
- Expectations: Radio axis has been measured (see run 8 daily report) to be 5mm left from centre (toward the M4 wall), and 1.5mm up from centre (toward ceiling).
- Measurement radio with ecosorb plate: roughly centred at +/- 3-4mm ; sky is too noisy to get better accuracy, so it's compatible with previous measurement; we will double check once the sky is good (it takes only about 10 minutes to check)
- Measurement laser spot on window removing M3 mirror: 3.5mm +/- 0.5mm up from centre when at 85° elevation, and 4.5mm +/- 0.5mm when at 0° elevation ; 3.5mm +/- 0.5mm left from centre when at 85° and 0° elevation.
==> ~2.5mm too high and ~1.5mm too much right w.r.t radio axis. Given the measurement errors, the effect on pupil alignment according to simulations (effect on pointing is even lower) we think it's preferable to let it as it is. Indeed below you can see the Zemax simulations of illumination of the primary by various field taken over the FOV (various positions on the array) with a good alignment and with the offsets we measured. The effects on the beam are negligible (changes of structure at 10-3 level), it's also negligible for pointing. Zemax can't simulated the effect of the asymmetric illumination of the primary; as long as we stay inside M1 we should be fine, but we might have a pretty small increase of background due to higher spillover.
We start the observations in poor weather (tau=0.5), and without a properly functioning turbo pump. Since Mars is bright, we'll track it for some beam maps.
April, 14th (Friday)
Alessia at the telescope and Juan remotely.
We started doing two dark scans. We tried to point using 3C84 but the source was far from the center -38,-20 arcsec. After discussions with Juan Peñalver we decided to use nasmyth offset computed by Nicolas on run 9: offsets -18.8 -5 /sys nasmyth, However, this did not solve either the problem. We switched to Mars but encountered the same problem. Finally, we found that the problem was related to a wrong reference kidpar - we corrected this and everything started work fine. However the weather during the day was very unstable although tau was not that bad: about 0.3-0.4 from IRAM taumeter. We have performed a small pointing session to verify the current model. We tried to get some Mars beammaps after focus X,Y, Z. We did a couple of skydips. Finally, we tried to go to PSZ2G144.85 to do a first test but had no enough time. Really a pity because the weather improved quite a lot.
Alessandro 22h45. I stop the turbo for the weekend. Plan to switch it ON on Monday in the late evening. Alessia, could you put the NIKA2 window back in place so we can check the noise between Monday and Tuesday ? Good night !