Radius metrics to compare to standard distortion corrected radii

[mgalloy]

There are 2 radii that would be useful to compare to the standard distortion corrected radii, {R,T}CAM_DCR:

• the radius of the distortion corrected flats
• the radius of the unflat-corrected, distortion corrected intensity

Tasks

• report 3 radii in the realtime log in one line

[mgalloy]

Here are the radii by the 3 difference methods for 20170531:

• "sci": our normal distortion corrected radius as reported in {R,T}CAM_DCR
• "dc gain": distortion corrected gain
• "dc ungain for sci": a distortion corrected, but not gain corrected science image

Here are the first 4 science files:

RCAM radii sci: 180.56, dc gain: 181.44, dc ungain cor sci: 180.59
TCAM radii sci: 180.14, dc gain: 180.79, dc ungain cor sci: 180.14
RCAM radii sci: 180.57, dc gain: 181.44, dc ungain cor sci: 180.56
TCAM radii sci: 180.16, dc gain: 180.79, dc ungain cor sci: 180.16
RCAM radii sci: 180.58, dc gain: 181.44, dc ungain cor sci: 180.57
TCAM radii sci: 180.16, dc gain: 180.79, dc ungain cor sci: 180.16
RCAM radii sci: 180.57, dc gain: 181.44, dc ungain cor sci: 180.58
TCAM radii sci: 180.17, dc gain: 180.79, dc ungain cor sci: 180.17

Full results.

[bberkeyU]

Is the correct understanding of this that the occulter radii as seen in the FLATS is larger than what we see in the SCIENCE files? [0.8arcseconds in RCAM and 0.4 arcseconds in TCAM]? And basically identical between flat correct and flat uncorrected science files?

Do we have a good explanation about why the flats are bigger? Is this diffraction of the disk light around the occutler apparently shrinking its radii? If so what does the flat radii give the "correct" result?

[mgalloy]

I agree with this:

Is the correct understanding of this that the occulter radii as seen in the FLATS is larger than what we see in the SCIENCE files? [0.8arcseconds in RCAM and 0.4 arcseconds in TCAM]? And basically identical between flat correct and flat uncorrected science files?

I'm not sure of the explanation. Eliminating the easy stuff: the cal file used, and hence the flats used, for flat fielding are from the same day, so the occulter for everything is OC-1006.9". We are comparing apples to apples.

[mgalloy]

@bberkeyU made some comments and a plot via email that I didn't want to lose:

I have plotted Mikes's table for RCAM/TCAM and the 3 flavors of measurement vs time. It shouldn't be surprising that the flat-only value is constant for the whole day since it was based on one image. But we can see the radii change over the observing day for the other two calculations, NORMAL and SCI, without flat.

"One Does Not Simply" meme omitted.