Differences between revisions 10 and 14 (spanning 4 versions)

Observation campaign description

Detailled description of specific observing sessions are given here.

Contents

Observation campaign description
1. Focus z campaign

Focus z campaign

Aim of the focus campaign : characterize how the focus evolves accross NIKA2 field of view

Method: the optimal axial focus is estimated from 5 x 1 arcmin square OTF scans at 5 different focus around the initial focus set in PAKO. In each map produced using NK_RTA, the main beam is fitted using a 2D Gaussian function. Two optimal z focus estimates are fitted using NK_FOCUS_LISS_OLD, which resorts to a polynomial POLY_FIT function: the focus z that maximises the flux at the beam peak and the focus z that minimizes the main beam FWHM, the former being usually more precise.

Analysis: Several focus z campaigns were done during NIKA2 run 3, and were analysed. For information, a compilation of the results is available in the NIKA2 private page in [[]].

'referent person: Laurence Perotto (laurence.perotto@lpsc.in2p3.fr), Jean-François Lestrade'

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

-  ⇤ ← Revision 10 as of 2016-02-26 13:19:50 → 
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+   ← Revision 14 as of 2016-02-26 13:32:25 → ⇥
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  Editor: NikaBolometer
  Comment:
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+Additions are marked like this.
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-focus campaigns were conducted on the 24th and 25th of January
+'''''Method:''''' the optimal axial focus is estimated from 5 x 1 arcmin square OTF scans at 5 different focus around the initial focus set in PAKO. In each map produced using NK_RTA, the main beam is fitted using a 2D Gaussian function. Two optimal z focus estimates are fitted using NK_FOCUS_LISS_OLD, which resorts to a polynomial POLY_FIT function: the focus z that maximises the flux at the beam peak and the focus z that minimizes the main beam FWHM, the former being usually more precise.
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-referent person: Jean-Francois Lestrade, Laurence Perotto
+'''''Analysis:''''' Several focus z campaigns were done during NIKA2 run 3, and were analysed. For information, a compilation of the results is available in the NIKA2 private page in [[]].
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-## source selection:
+''''referent person: Laurence Perotto (laurence.perotto@lpsc.in2p3.fr), Jean-François Lestrade''''


=== 1./ source selection ===
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-# pointing correction
+=== 2./ pointing correction ===
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+  {{{
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+}}}
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+{{{   
      PAKO>set pointing xx yy
}}}
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-      PAKO>set pointing xx yy
+=== 3./ best focus at the array center f_0 ===
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-# best focus at the array center f_0:
+{{{
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+enter 0 as the center focus f.
}}}
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-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:
+It will run 5 scans at focus f-0.8; f-0.4; f; f+0.4; f+0.8
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+Analyse each scan individualy using:

{{{
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+}}}
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+{{{
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+}}}
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+=== 4./ best focus across the field-of-view f_{off-center} ===
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-# best focus across the field-of-view f_{off-center}:
+{{{
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+enter 0 as the center focus f.
}}}
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-enter 0 as the center focus f.
+Analyse each scan individualy using:
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-analyse each scan individualy using:
+{{{
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+}}}
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+{{{
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+}}}
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+{{{
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+}}}
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-# monitoring of the focus temporal drift'
+=== 5./ monitoring of the focus temporal drift ===

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