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## source selection: | === source selection === |
Observation campaign description
Detailled description of specific observing sessions are given here.
Focus z campaign
- Aim of the focus campaign : characterize how the focus evolves accross NIKA2 field of view
2 focus campaigns were conducted on the 24th and 25th of January
referent person: Jean-Francois Lestrade, Laurence Perotto
source selection
Choose a bright point source of several Jy (e.g. 3C273)'
PAKO> source 3C273 PAKO> track PAKO> start
# pointing correction
pointing lissajous seems more reliable as the reference pixel is currently (25/01) off-centered
PAKO>@nkpoint l PAKO>@nkpoint b
in case of poor fit with a lissajous, try resorting to the 'common_mode_kids_out' method" IDL> nk_rta, 'scan', /mask
PAKO>set pointing xx yy
# best focus at the array center f_0:
PAKO>offset 0. 0. \sys nasmyth PAKO>@focusOTF
enter 0 as the center focus f. It will run 5 scans at focus f-0.8; f-0.4; f; f+0.4; f+0.8 analyse each scan individualy using:
IDL> nk_rta, 'scan', /nas
once the 5 scans are reduced, run (for ex.):
IDL> nk_focus_liss_old, '20160125s'+strtrim([1,2,3,4,5], 2), /nas
# best focus across the field-of-view f_{off-center}:
PAKO>offset xoff yoff \sys nasmyth PAKO>@focusOTF
enter 0 as the center focus f.
analyse each scan individualy using:
IDL> nk_rta, 'scan', /nas, /xyguess, /largemap
once the 5 scans are reduced, run (for ex.):
IDL> nk_focus_liss_old, '20160125s'+strtrim([1,2,3,4,5], 2), /nas, /xyguess
Please keep track of the (xoff, yoff) in TAPAS for easier analysis of the campaign results the list of nasmyth coordinates to be explored can be read on the A2 printed sheet In case the focus@1mm and the focus@2mm are very discrepant, the focus exploration bin (-0.8, +0.8) may be not sufficient to fit simultaneously f_1 and f_2. Relaunch using f=<f_2>, the focus@2mm value from the previous focus campaign measurements:"
PAKO>@focusOTF
enter <f_2> as the center focus f.
# monitoring of the focus temporal drift'
Since we are interested in the difference between f_0 and various f_{off-center}, f_0 should be regularly checked (every point or every other point depending on its stability)
re-iterate 3/ from time to time