Pinhole Focus Tests

We took a series of images of the pinhole with different # of turns on the echelle mirror and echelon mirror. We measured the FWHM of the C2H2 Q-branch 9-13 lines (729.5-730.0 cm^-1), reporting the median values and the standard deviations. The best spatial focus for the median resolution mode was obtained with 11 turns on the echelle mirror (found in a previous test during CD13).

 The values below show that better focus can be obtained in the high-medium mode with 13 or 15 turns on the echelle mirror. This probably means that the detector should be at a different location to accommodate the best focus for these modes simultaneously. We will also see if even better results can be obtained for 17 (and 19?) turns on the echelle mirror.

All files can be found in B_12_02_03/
 

#filename    echelle_position echelon_position spatial_FWHM stddev(spatial_FWHM) spectral_FWHM

b652.fits    11    20.5     8.76    0.40     8.27    0.47
b653.fits    11    20.5    10.17    0.87     8.41    0.64
b654.fits    11    18.5    10.53    0.94     8.43    0.66
b655.fits    11    16.5    16.15    2.57    11.02    1.25
b656.fits    11    14.5    19.83    4.71    14.53    1.34
b657.fits    11    12.5    23.34    9.42    18.67    1.46
b658.fits    11    20.5     9.37    1.15     8.38    0.66
b659.fits    11    22.5     9.56    1.18     8.83    0.71
b660.fits    11    24.5     8.92    1.18     9.94    0.78
b661.fits    11    26.5     9.42    1.34    11.75    1.13
b662.fits    11    28.5    10.41    1.32    14.11    1.86
b663.fits    11    30.5    11.68    1.27    17.26    2.59
b664.fits     7    30.5    10.46    1.25    13.54    1.48
b665.fits     7    28.5     9.84    1.20    11.47    0.99
b666.fits     7    26.5    10.01    1.13    10.08    1.04
b667.fits     7    24.5    10.86    1.13     9.47    0.85
b668.fits     7    22.5    11.23    1.18     9.30    0.87
b669.fits     7    20.5    12.93    0.82     9.82    1.06
b670.fits     7    18.5    16.55    5.23    11.35    1.39
b672.fits     7    16.5    19.99    3.72    14.13    1.51
b673.fits     7    14.5     0.00    0.00    17.47    2.00
b674.fits     7    12.5     0.00    0.00    22.06    2.03
b675.fits     7    10.5     0.00    0.00    26.96    3.58
b676.fits     7    10.5     0.00    0.00    26.59    1.74
b677.fits     9    10.5     0.00    0.00    22.94    3.65
b678.fits     9    12.5     0.00    0.00    17.99    1.88
b679.fits     9    14.5    16.32    2.97    14.67    1.48
b680.fits     9    16.5    14.18    3.11    11.23    1.39
b681.fits     9    18.5    11.40    1.32     9.58    0.94
b682.fits     9    20.5     9.25    0.45     8.88    0.73
b683.fits     9    22.5     8.78    0.42     8.90    0.71
b684.fits     9    24.5     8.15    0.52     9.37    0.71
b685.fits     9    26.5     8.29    0.71    10.48    0.78
b686.fits     9    28.5     7.89    1.79    12.27    1.06
b687.fits     9    30.5     9.18    0.82    15.07    1.72
b688.fits    13    30.5    11.61    1.15    19.85    2.31
b689.fits    13    28.5     9.63    0.92    16.22    1.91
b690.fits    13    26.5     8.52    0.78    12.98    1.60
b691.fits    13    24.5     7.70    0.73    10.53    0.80
b692.fits    13    22.5     7.35    0.66     8.88    0.68
b693.fits    13    20.5     7.37    0.61     8.08    0.52
b694.fits    13    18.5     8.10    0.68     7.75    0.49
b695.fits    13    16.5     9.04    0.78     7.84    0.59
b696.fits    13    14.5    11.04    1.62     8.97    0.89
b697.fits    13    12.5    15.54    2.64    10.88    1.25
b698.fits    13    10.5    21.45    3.51    14.58    1.46
b699.fits    15    10.5    15.87    1.98    11.33    1.18
b700.fits    15    12.5    11.23    1.32     8.52    0.80
b701.fits    15    14.5     8.81    0.61     7.61    0.49
b702.fits    15    16.5     7.94    0.73     7.35    0.42
b703.fits    15    18.5     7.21    0.40     7.63    0.40
b704.fits    15    20.5     7.11    0.64     8.31    0.45
b705.fits    15    22.5     7.61    0.68     9.75    0.64
b706.fits    15    24.5     8.10    0.66    12.25    1.15
b707.fits    15    26.5     9.54    0.87    15.33    1.67
b708.fits    15    28.5    11.30    0.66    19.05    2.00
b709.fits    15    30.5    13.54    0.89    23.22    2.10

Stray light in high-med at 13.7 microns

I looked at data comparing looking at the room at the Q-branch in high-med mode with the same setup looking at the lens wheel dark.  The data were 16 destructive coadds with 110 ctdelay (3 seconds).

I rotated the image using IDL rot() to get orders to mostly run along columns.  I then plotted rows 200-800 normalized to ADU/seconds and as a fraction of the row peak (actually, row 98th %ile).  Plot is below.

The short answer is I think we have scattered light at this setting of <=25 ADU/sec.  We'll enter this into the table.

CD13 Pupil mode extra light

At the IRTF, we saw lots of extra light in pupil mode when we weren't actually letting light into the optics box.  See a post in Aug/Sep(?) 2012 for the images.

Before CD13, we taped various holes in the optics box closed.  The pupil image below shows that we got rid of our extraneous light in the optics box.  This doesn't mean we've avoided scattered light.  In fact, some scattered light is present in the pupil image at a hard stretch.

The data come from 110 ctdelay SUTR with 4 samples.  I'm plotting the difference between frame 0 and frame 3 (9 second total integration) and the difference between having a basically closed optics box (5 micron filter, pinhole crossed with decker between dashes and slit/filter, and flip mirror halfway between settings) and one in normal pupil mode with 5 micron light.

The punchline is that we got rid of the light sources in the optics box that showed up at the IRTF.  Another post will evaluate scattered light contribution in hi-med mode....

Sample Filter Scan

Here is a sample scan of the 7.9 micron filter over our (pot-limited) range of echelle motion. It's collected using the 'strip chart' mode of the photometry boxes in Justin's GUI, and the resulting graph is measured via the GIMP to get start/end points for the orders:

The values across the top give the pot voltage and corresponding angle for the rough center of each order.

The green line is the mean over a rectangular box oriented vertically, quasi-parallel to the echelon orders.  Blue is a similar box rotated 90 degrees, across the orders.

The echelle is rotating slowly as the strip chart is collected, at about 1.5 degrees/minute.  The central decker is set across the flux slit to create narrow orders, though they overlap from time to time.

This is meant to provide an overview of the filter profiles.  We'll need to use the measured central order positions to go back and obtain representative frames at each order, determine appropriate slit lengths, etc. I'm collecting the scans and the GIMPed measurements in a spreadsheet....any suggestions are welcome.

'Opus' Metrics

This post is meant to serve as a shorthand instrument capability table, and to reflect where we stand relative to the 'opus' capabilities document for EXES.  To be updated as test data are analyzed.....

Parameter	Requirement	Goal	Measured	Verification/Comment
Full-Frame Rate	1Hz	6Hz	2Hz	CD13
Read Noise	70 rms e-	50 rms e-	60 rms e-	Single-sample, bench dewar
Dark Current	10 e-/s	1 e-/s	0.1 e-/s	Array blanked, bench dewar
Wavelength Range	4.5-28.3um	4.5-28.3um	4.5-28.3um	Lab Test
Wavelength Range	4.5-28.3um	4.5-28.3um	4.5-28.3um	Lab Test
Response	50%	60%	TBD	@ 5um
	50%	60%	TBD	@10um
	50%	60%	TBD	@15um
	50%	60%	TBD	@20um
	50%	60%	TBD	@25um