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PointingModelOffsets » History » Version 4

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Lucas Beaufore, 07/12/2013 12:23 PM


Pointing Model Offsets

In order to study the effects the pointing model may have on the offsets, new offsets were calculated with possible corrections from the effects of the hexapod trim values.

The following histograms show the distribution of the offsets before trim corrections, and with a trim correction of both addition and subtraction.

RA offset with: No correction, addition of a scaled (.0176 arcsec/micron) trim_dy value, subtraction of the scaled trim_dy value

Dec offset with: No correction, addition of a scaled (.0176 arcsec/micron) trim_dx value, subtraction of the scaled trim_dx value

The effect of the corrections are arguably more visible on a 3D plot. The following show the tweak values and exposure ID values (essentially time, in order to better show the exposure groups)
versus the offsets.

Declination offsets vs trim_dy (vs expid):

!{width:100%}dec_all_corrections_back.png
!{width:100%}ra_all_corrections_side.png