REVISION DATE: 14-Feb-2017 17:12:38

Mike did a quick exposure time cal. Using Mike detailed email and the int cal from Hawaii-2016-01 day 7 I calculated a calibrated integration times. My method differed from Mikes in that I meaned all the 1 sec and 10 sec data so I normalized by the mean a 1 sec etc. See explainations below for more details about each step. Note: Data are in ADU/pix (the per pixel is because this is a track mean). They are all NET signals (lite - backgrounds)

 
% File: \data\2017\HI-2017-01\BS01data\ascii_out\BS01_exptimecal(rev13Feb2017).txt 
% Date: 13-Feb-2017;  by: MF/MLML 
% What: 12-Feb-2017 pre-MOBY262 BS01cfg007 LuBot Exposure Time Calibration via OL455-18U 
% 
% Contents: 
% Column 1 = Nominal Exposure Time (sec) 
% Column 2 = Calibrated Exposure Time (sec) 
% Column 3 = Approximate Uncertainty in Calibrated Exposure Time (sec) 
% 
 0.05    0.09427829  0.0009690218 
 0.07    0.1134268  0.0009694974 
 0.1     0.1417515   0.001114091 
 0.2     0.2368882    0.00125844 
 0.3     0.3319896   0.001251888 
 0.5      0.522174   0.001540753 
 0.7     0.7121558   0.001661241 
   1             1             0 
   2      1.952422    0.01245284 
   3      2.913429    0.01624143 
   5      4.833348    0.02705334 
   7      6.756649    0.04205685 
  10      9.653902    0.06396895 
  20      19.24042     0.2279321 
  30      28.90868     0.2824454 
  50      48.40306     0.4149921 
  70      67.53256     0.7713569 
 100      96.70038      1.200514

The data where collected a three different lamp levels ("Brite", "Mid", and "Dim") to be able to get a full range of integration times. You can see all the levels here.

Figure 1

Track 13 data normalized using the step down ratios. So the 1 sec repeats from Bright to Mid and the 10 sec repeats from Mid to Dim plot on top of each other.

Figure 2

I am not totally sure what this graph is showing but I copied it from Mikes email. Email section below: I checked the Net Sig repeats at 1 sec for the Brite lamp (+/- 0.5%), and at 1 sec for the Mid lamp (+/- 1%), and at 10 sec for the Dim lamp (+/- 1.5%).Since they seemed OK, and the PD mon repeats were essentially 1, I did my Net Sig "normalizing" to the nearest-in-time 1 sec exposure Net Sig at Brite & Mid lamp settings, and to the nearest-in-time 10 sec net at Dim lamp setting(hopefully this will make sense below!). Yea, it looks the same as Mikes, now I need to understand what we are checking for here.

Figure 3

Checking the integration time repeatability within each lamp level. So I found all the Brite 1 sec and divided by the mean to get the variation about the mean. I did the same for the 1 sec Mid and 10 sec Dim data. This looked really good.

Figure 4

The Photodiode data normalized to the level changes using PDmonitor data.

Figure 5

The left panel is the Same data from Figure 2. The right panel is each int time divided by the mean 1 sec data and integration time. I then calculated the mean for each ratio from pixels 300-900 and a std.

Figure 6

A plot of the ratio of measured over nominal Exposure time.

Figure 7

Zoomed in to the higher int time numbers with error bars.

Figure 8

Figure 9