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Home All issues Volume 520 (September-October 2010) A&A, 520 (2010) A2 Full HTML

 

 

Table 4:

Planck reflector characteristics at ambient temperature and 40 K.

Reflector 		Design parameter Ambient temperaturea Estimated in-flight parameter Estimated uncertainty
PR $R=1440.0~{\rm mm}$ $R=1440.41~{\rm mm}$ $R=1439.266~{\rm mm}$ ${\pm}0.1~{\rm mm}$
  k=-0.869417 k=-0.86782 k=-0.867266 $\pm 0.001$
  $\rm rms~(ring~1, \mu m)= $ 7.5 3.5 5.0b  
  rms (ring 2, $\rm\mu m)= $ 12 4.2 8.2  
  rms (ring 3, $\rm\mu m)= $ 20 5.3 8.8  
  rms (ring 4, $\rm\mu m)= $ 33 6.0 8.6  
  rms (ring 5, $\rm\mu m)= $ 50 16.0 12.6  
  rms (whole surface, $\rm\mu m)= $ 7.0 8.6  
SR $R=643.972~{\rm mm}$ $R=644.043~{\rm mm}$ $R=643.898~{\rm mm}$ ${\pm}0.1~{\rm mm}$
  k=-0.215424 k=-0.21541 k=-0.215094 $\pm 0.001$
  rms (ring 1, $\rm\mu m)= $ 7.5 3.6 4.7c  
  rms (ring 2, $\rm\mu m)= $ 12 3.9 4.5  
  rms (ring 3, $\rm\mu m)= $ 20 6.2 7.0  
  rms (ring 4, $\rm\mu m)= $ 33 5.3 5.7  
  rms (ring 5, $\rm\mu m)= $ 50 11.5 13.2  
  rms (whole surface, $\rm\mu m)= $ 6.1 10.6  
  Core-wall print-through $\rm (\pm \mu m)= $d   0.4  
  PTV (dimpling, $\rm\mu m)= $e   <0.7  

Notes. (a) All rms at room temperature derived from the surface shape measured with a contact probe and a resolution of 2 cm. The ring definition is as in Table 1.
(b) Derived from the photogrammetric image of Fig. 7. The rms values quoted are actually standard deviations of the distribution of values in each ring, i.e. they are with respect to the mean difference to the best-fit-ellipsoid within each ring. A real rms with respect to the best-fit-ellipsoid would increase the rms in the innermost ring by a factor of $\sim $4 - largely due to the prominent bump visible in the middle of the primary in Fig. 7, and of the next two rings by a smaller factor.
(c) Derived from the interferometric image of Fig. 6. The rms values quoted are actually standard deviations of the distribution of values in each ring, i.e. they are with respect to the mean difference to the best-fit-ellipsoid within each ring. A real rms with respect to the best-fit-ellipsoid would increase the rms in the inner two rings by a factor of $\sim $2 - largely due to the circular shelf-like feature visible in Fig. 7 and associated to the three ISMs. It is also interesting to note that the combination of interferometric data to the photogrammetric data has increased the rms by about 15% as compared to the photogrammetric surface only.
(d) Not measured for the PR.
(e) Not measured for the PR.


Source LaTeX | All tables | In the text

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