Changes
SHOC
,/* LED timing tests */
===LED timing tests===
''Currently, this This functionality is only should be available on the 74". Eventually, it should also be on the 40" and the new 1m. It has only been tested on the 74".''The idea is to take a long, GPS-triggered data cube with SHOC at high cadence, while running the LED for a few minutes of 1 PPS (which has a longer pulse on the minute and can thus be used to test absolute timing accuracy), then switching the LED to approximately a minute or so for at least 2 other settings e.g. 5Hz, 2 Hz (which can be aligned with the observed flashes to test relative timing accuracy).
*There is an LED mounted in the telescope optical path that can be used to independently verify SHOC timing. Log into the following website:
[[image:74inLEDPulseWebsite.jpg|500px]]
*Instructions Check that the LED is visible by turning on what data a pulse and seeing if it is apparent in the preview images. For example, take 0.2-s exposure and set the LED to 1 PPS, then look for increased counts/flashes on the display every 5th frame.* '''To take a timing data cube:''' ** start the LED at 1 PPS** in preview mode, increase the SHOC binning to reach the desired exposure cadence (< 0.05s). ** set SHOC to external timing, select >=10000 frames, and how start the GPS with repeated pulses at the chosen cadence** after a few minutes, select a different LED frequency (e.g. 5 Hz)** after a minute or so, select a different LED frequency (e.g. 2 Hz)** after a minute or so, select a different LED frequency (e.g. 10 Hz)** after a minute or so, select a different LED frequency (e.g. 1PPS)** REMEMBER TO TURN OFF THE LED PULSES WHEN DONE.* '''Analysis:''' you are free to analyze will be posted soonyour own timing data! Otherwise, an analysis pipeline has been written by Marissa Kotze and is supported by Carel van Gend. Carel can assist with data analysis.
== In-depth Information ==
