focus
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| - | Focus Sequence | ||
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| - | Use //Run Focus// in the AzCam window to make a focus exposure sequence. | ||
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| - | A new instrument command has been added to move the focus actuators to specific LVDT values. | ||
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| - | // | ||
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| - | to move the actuators (A,B,C) to the positions indicated. | ||
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| - | Misc Focus Info | ||
| - | * The image header has a line like: FOCUSVAL= ' | ||
| - | * These are LVDT (encoder) values corresponding to ' | ||
| - | * One focus actuator step is 2.645 microns, which corresponds to -0.0005 LVDT units. So the conversion is (-1322.5 um/LVDT unit). | ||
| - | * Note the zero point for the LVDT scale is arbitrary and only relative motion should be considered.So for example, 0.756 above for LVDT_A is a position of (0.754 * -1322.5) = -997.2 microns. | ||
| - | * Note the direction sign is reversed between actuator movement and the LVDT readout. | ||
focus.1564440549.txt.gz ยท Last modified: 2019/07/29 15:49 by davner
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