HI 1A - Raw Image

HI 1A – Shutterless/Flatfield Corrected Image (secchi_prep)

HI 1A – Bloom removed image

HI 1A – Background subtracted image

Starfield fitting for alignment

HI Calibration ParametersHI 1A HI 2A

Pre-flight Stars Pre-flight Stars

HI x offset (°) -13.98 -13.9789±0.0001 -53.68 -53.51±0.02

HI y offset (°) 0.00 0.075±0.002 0.00 0.23±0.02

HI roll (°) 0.00 1.0241±0.0001 0.00 0.130±0.001

Distortion parameter (μ)

0.16677 0.146±0.006 0.83329 0.820±0.002

Fparaxial (mm) - 77.4263 - 21.4311

Platescale (degrees/pixel)

0.009977 0.00999006 0.036047 0.0360921

CCD x offset (bins)

0.00 -0.068±0.007 0.00 -1.9±0.2

CCD y offset (bins)

0.00 -1.31±0.08 0.00 1.9±0.3

HI Calibration ParametersHI 1B HI 2B

Pre-flight Stars Pre-flight Stars

HI x offset (°) 13.98 14.185±0.006 53.68 53.2±0.2

HI y offset (°) 0.00 0.022±0.002 0.00 0.7±0.2

HI roll (°) 0.00 0.30141±8x10-5 0.00 -0.6±0.4

Distortion parameter (μ)

0.10001 0.1581±0.0006 0.65062 -0.820±0.001

Fparaxial (mm) - 77.6297 - -

Platescale (degrees per pixel)

0.0099625408 0.00996388 0.0359479 -

CCD x offset (bins)

0.00 -0.5±0.3 0.00 -6.5±0.8

CCD y offset (bins)

0.00 -0.9±0.1 0.00 -3±2

HI 1A – Star removal image

HI 2A – Milky Way

HI 2A – Magellanic Clouds

HI 1A – small-scale flatfield

1.Take series of images (at least 3)2.Find the minimum value per pixel3.Low-pass filter this background4.Pixel-to-pixel variations are the

difference between the two over small areas of the CCD

5.Do this many times to build up statistics for each pixel

HI 1A – small-scale flatfield

HI 1A – small-scale flatfield

HI 1A – small-scale flatfield uncertainties

HI 1A – large-scale flatfield

1. Identify stars in image2.Wait for them to drift through the field of

view3.Measure the variation in their intensities

as they do so.4.Do this for many stars.

HI 1A – large-scale flatfield