Differences

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--- calibration [2025/10/11 00:02] – holtz
+++ calibration [2026/06/02 21:18] (current) – holtz
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 ===Position===
-The calibration spot moves up and down as the calstage is moved. To move the calibration stage left/right one needs to adjust one of the screws on the mirror mount for the mirror in front of the Shelyak. I believe that turning the top screw CW (from behind the mirror) moves the spot to the right.
+The calibration spot moves up and down as the calibration stage is moved. To move the calibration stage left/right one needs to adjust one of the screws on the mirror mount for the mirror in front of the Shelyak. I believe that turning the top screw CW (from behind the mirror) moves the spot to the right.
 To position the calibration spot with the iodine cell, the cell can be tilted by adjusting the three screw on the front ring. Need to take care not to overtighten and potentially break the cell, so adjustments should be made by both loosening some screws and tightening others! Moving the cell with the bottom two screws (one in, one out) should move spot left/right, moving the cell with compensating motions of top screw and the bottom two together should move spot up/down.
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 Given the fibers in the focal plane, it's not possible to illuminate all of the pixels in the detector with light coming through the fibers. One doesn't want to flat field with the calibration light because of all of the pixels with low/zero light levels.
-We obtained some pixel flats by removing the fiber input assembly and putting a diffuse light source (an LED lamp with a piece of paper over it) to get illumination across the whole chip:
+We obtained some pixel flats by removing the fiber input assembly and putting a diffuse light source (an LED lamp with a piece of paper over it) to get illumination across the whole chip. Subsequently we achieved these using a penlight wrapped in bubble wrap which can be inserted in the upper assembly without  moving the fiber input assembly at all.
 {{:test:pixflat.png?direct&200}}
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 ====Wavelength calibration====
+====Stability====
+Sequences of calibration frames:
+- UT2510xx : flats and ThAr through fiber 2 (science) every half hour for 12+ hours
+- UT251011 : flats and ThAr through both fiber 1 (direct) and fiber 2 (science) every half hour for 12+ hours