Last updated July 19, 2006

This document is to outline the hardware defects measured in the H and V arrays during the july run of the SHARP team.  Such defects include: translational misalignment between the H and V arrays, rotational misalignment between the H and V arrays, and the stretch factors for both arrays.  

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Rotation Misalignment
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*Darren Dowell's Results*

ROTATOR_0 (V) = 2.4 degrees
ROTATOR_0 (H) = -0.8 degrees

Both of the above angles are between the array and the telescope coordinate systems.  Note that a positive angle implies a clockwise rotation in sky coordinates.  This implies a total angular displacement of 3.2 degrees between the two arrays (No margins of error are given).

*Hua-bai Li's Results*

A total rotational displacement of 2.0+/-1.4 degrees was measured with the V array being rotated clockwise wrt the H array.  

Open question: was this measurement made in 'quicklook' space or is it sky right?  If these measurements are sky right, then this would be consistent with Darren's result.  

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Stretch Factors
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*Darren's Results*

SCALE (V) = 4.73 arcsec/bolometer pixel
SCALE (H) = 4.78 arcsec/bolometer pixel
DISTORT (V) = 1.030
DISTORT (H) = 1.045
Vx scale = SCALE*DISTORT = (4.73)(1.03) = 4.87
Vy scale = SCALE/DISTORT = (4.73)/(1.03) = 4.59
Hx scale = SCALE*DISTORT = (4.78)(1.045) = 4.99
Hy scale = SCALE/DISTORT = (4.78)/(1.045) = 4.57

So now if we take the V:H ratio in the x and y directions:

x direction -> V:H = 4.87:4.99 ~ 1:1.026 or 0.97:1
y direction -> V:H = 4.59:4.57 ~ 1:1

*Hua-bi Li's Results*

The stretch displacements between the V and H arrays were found to be:

x direction -> V:H = 1:0.96
y direction -> V:H = 1:1

There is a discrepancy here between the two measurements of the V:H ratio for the x direction along the array.  This might be explained if Hua-bai is defining his stretches in terms of arc seconds per bolometer pixel?

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Translational Misalignment
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I have examined most of the Jupiter data taken on the 12th, 13th, and 14th of the July 06 run.  Using quicklook and fitgauss, I have completed an analysis that indicates a translational misalignment between the H and V arrays of ~ (x direction: 0 pixels, y direction: 0.1 pixels).  Note that the array differences were evaluated as H-V and this misalignment is given in 'quicklook' space, which is the same format as the output from sharpinteg.  See the excel sheet that accompanies this memo for more details about this analysis.