Observation campaign description

Detailled description of specific observing sessions are given here.

Back to the NIKA2 Run4 page

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

1./ source selection

Choose a bright point source of several Jy (e.g. 3C273)'

      PAKO> source 3C273
      PAKO> track
      PAKO> start

2./ 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

3./ 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

4./ 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.

5./ 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