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About 1pm the wind calmed down while fog was still very present. We started the joint EMIR/NIKA2 skydip session |
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February, 21st (Tuesday)
Martino, Alicia, Alessia, Juan, Charles, Florian, Jean François, Pablo arrived this morning, Nico was already here.
IMPORTANT NOTE ON ALIGNEMENT: during maintenance, the atmosphere was not very stable. So, finding the center of the pupil by moving the eccosorb foil in front of the window was impossible: the signal produced by the eccosorb was comparable to the oscillations of the atmosphere, unless we entered pretty 'violently' in front of the window. We guess that we could have achieved a precision of (maybe?) 1cm, so decided to keep as good the previous position, found during run 8. Mounting the laser, Santiago, Dave, Alicia and Martino found that the spot was 1cm off from where it should be (1cm higher). This lead them to move M6 to fix it: a 1cm decrease of the whole cryostat seemed unlikely.. For the time being, we accept this configuration.
On a happier note: the noise in the KID traces seemed at first glance to be pretty good. The PT only give a few rays in the spectra, no signs of the big 'bump' that was present in January and that hints to a touch between PT and 4K plate. So maybe the pressure cycle of the gain helped us in this sense. But, be careful: to confirm on a good and stable sky!
16h30 : Wind is still too high to start observing. Weather seems pretty opaque and the forecasts are not good so far.
17h30 or so: started observing! But, high tau and a lot of wind, unstable atmosphere and KID noise largely dominated by atmospheric effects. Stopped at 20h due to high wind. It looks like we'll have to wait a couple of days before having better weather. But, who knows, we might have good surprises!
Despite the weather conditions, we were able to do a few pointings : the action on M6 or the realignement overall induced a pointing shift of (17,15) arcsec ! We could also run one or two focus sequences and two skydips. Reducing the skydips, taking their C0 and C1 and putting them in the reference kidpar (that dates back to January) and re-analysing scan 21s51 that is not too far from a good focus, we find fluxes of 30Jy at 1mm and 13Jy at 2mm, when we expect 37 and 16. Given all the caveats, the high opacity (0.4 at 1mm) and the weather conditions overall, it's pretty encouraging !
February, 22nd (Wednesday)
No observations last night. This morning the wind is still too strong.
About 1pm the wind calmed down while fog was still very present. We started the joint EMIR/NIKA2 skydip session