Gillam ASI (Wilbur) Alignment Data 1992-1999

Year	column	row	k1	k2	alpha	beta	gamma	alpha+gamma
1992	125.9	127.3	n/a	n/a	n/a	0.4	n/a	5.8
1993	129.2	127.7	n/a	n/a	n/a	0.5	n/a	6.6
1994	121.8	130.1	0.624	8.28E-04	148.26	0.53	-141.79	6.5
1995a	125	129	0.624	8.28E-04	137.82	0.00	-137.60	0.22
1995b	130.0	126.0	0.624	8.28E-04	-163.36	0.00	163.40	0.03
1996	128.0	127.0	0.624	8.28E-04	-95.06	0.00	95.35	0.30
1997	131.0	127.0	0.624	8.28E-04	-120.58	0.00	120.56	-0.02
1998	130.8	125.5	0.624	8.28E-04	-149.40	0.00	149.39	-0.01
1999	131.5	124.8	0,624	8.28E-04	-149.31	0.00	149.33	0.01

NOTES:

column: CCD pixel col intersected by optical axis (as calculated from starfields)
row: CCD pixel row intersected by optical axis (as calculated from starfields)
k1 = 0.624315: linear coeff for the radial function (radial correction)
k2 = 0.000828: quadratic coeff for the radial function (radial correction)
alpha, beta, gamma: alignment rotation angles in degrees (see "supporting documentation").

There are two sets of 1995 data circulating, for some reason. 1995b is the "official" data delivered to the CSA.

Supporting Documentation:

Memo on lens projection (k1 and k2)
Memo on cropping, projection, k1 and k2 [ PDF ]
Calibration methodology report. Cf. "Step 6" therein [ PDF ]
ASI Alignment Appendix: more about alpha, beta, and gamma [ PDF ]
Calibration procedures in brief

Interpretation of the above tabulated data:

For example, the 1996 data...:

Azimuthal misalignment is here 0.03 degrees (alpha+gamma). I.e., the optical axis coordinate system is rotated 0.03 degrees in West-to-North (presumably) direction. See ASI Alignment Appendix above. Azimuth is probably zero toward the South, and may be increasing Eastward, but nobody really knows anymore. There are conflicting statements in literature. (We do know which way is up).
The optical axis is tilted 0.00 degrees (beta) off from zenith. 1996 was a pretty cool year for tilt.
The optical center is:
- 128.0 degrees East -> West (columns)
- 127.0 degrees North -> South (rows)

TST / 9 JANUARY 2003