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Processing of the June 2025 NIKA2 Re-Commissioning
PIIC reduction of the 20250612s43 beam-map
During the first half of run 73, only one beam map was taken.
SB, 2025/06/12 @18:20 LT: The beam map is scan 20250612s43. Results of a quick analysis of the beam map: the quality of the beam map (sky, telescope, focus, etc.) is unfortunately not good enough for making new (preliminary) Ar1 and Ar3 DAFs. Below you see the classic FOV beam-map figure. Ar3 is much worse than Ar1 likely because the best focus difference that affects it. Nevertheless, also Ar1 is unusable.
On the bright side: the central KID (Ar2, KC016, PIIC id 363) is definitely back! Yay!
PIIC reduction of the 20250616-18 beam-maps
During the second half of run 73, six beam maps have been taken, namely:
20250616s179 |
focus Ar2-1 |
3C273 |
20250616s181 |
focus Ar3 |
3C273 |
20250617s49 |
focus Ar2-1 |
2251+158 |
20250617s51 |
focus Ar3 |
2251+158 |
20250618s83 |
focus Ar2-1 |
2251+158 |
20250618s90 |
focus Ar3 |
2251+158 |
SB reduces them of 2025/06/24-....
Impressions:
- overall the conditions were better than during the first half of run 73 (2025/06/12), but still sub-optimal
- s51 does not seem very well focused on Ar3. As a matter of fact it is pretty decent also for Ar1.
- s181 and s179 seem to have a similar focus (both are extremely bad for Ar3)
Ar3 seems to have problems. I don't know if it's a problem of focus or a problem of boxes noise. It might also be coincidential worse weather during the Ar3-focused scans than during the Ar2-focused ones. The feeling is that the Ar3 behaviour in run 73 is different with respect to run 72 (see N2R72 daily report, 20250324s58), in terms of either focus, boxes noise, or both, or else. Many Ar3 KIDs are lost even in the Ar3 best beam maps (20250617s51 and 20250618s90)
- best beam maps of run 73: Ar2 20250618s83; Ar1 20250618s83; Ar3 20250617s51 and 20250618s90.
The plots below show the best beam map for each of the three arrays. For Ar3, I inlcude both the "best" beam maps of run 73. As you can see the result of Ar3 is still sub-optimal.
My feeling is that the focus offset of Ar3 wrt the other reached now a critical level, provided that this is the only problem and that there are no other issues with some other optical element (the polarizer? the arrays "z" angle wrt their optical axis? else?). If confirmed, I think that this should be fixed.
Therefore, I decide that I do not apply any change sto the DAFs RPPs. In practice, we only have one decent Ar1 beam map in this run 73. The Ar2 RPPs are already in good and centered on the central KID (Ar2 RPPs of NIKA2 run 68). For Ar3 I do not have any good beam map to make good RPPs refereed to the same central KID.
Therefore, I decide to keep the same RPP scheme used during run 73: Ar2 centered on the good old central KID; Ar1 and Ar3 produced in run 72 and affected by an offset wrt Ar2. When there will be good beam maps for Ar1 and Ar3 (at least 2 beam maps each), I will make again the RPPs for Ar1 and Ar3, centered on the good central KID. For now we keep the offset between Ar2 and Ar1/3. When you'll see this offset at the telescope DO NOT PANIC. It's all ok, and it's on purpose. For further explanations see these notes in the run 73 daily report, as well as the emails exchange of 2025/06/10.
2025/05/26 I have therefore installed this mixed set of DAFs as default, keeping the pure-run-72 version as backup (write me if needed).