The offset angle between the STIS aperture axis and the spacecraft orientation reference vector U3 is about 45 degress for the STIS spectroscopic apertures. However, observers should be aware that each STIS aperture has a specific U3 offset angle which is close to, but not equal to 45-degrees. In Table 1 we list the precise offset angles for all available spectroscopic slits. Uncertainties of the offset angles are typically +/- 0.05 degrees.
| STIS Aperture |
Offset Angle |
STIS Aperture |
Offset Angle |
|---|---|---|---|
| 2X2 |
44.94 |
0.1X0.06 |
44.94 |
| 0.1X0.09 |
44.94 |
0.1X0.2 |
44.94 |
| 0.2X0.06 |
44.94 |
0.2X0.09 |
44.94 |
| 0.2X0.2 |
44.94 |
0.3X0.06 |
44.94 |
| 0.3X0.09 |
44.94 |
0.3X0.2 |
44.94 |
| 1X0.06 |
45.15 |
1X0.2 |
44.94 |
| 0.2X0.5 |
44.95 |
6X0.06 |
45.28 |
| 6X0.2 |
45.31 |
0.1X0.03 |
44.94 |
| 0.5X0.5 |
44.94 |
6X0.5 |
45.31 |
| 6X6 |
44.94 |
52X0.05 |
45.28 |
| 52X0.1 |
45.02 |
52X0.2 |
45.02 |
| 52X0.5 |
45.38 |
52X2 |
45.04 |
| 0.2X0.06FPA |
44.94 | 0.2X0.06FPB |
44.94 |
| 0.2X0.06FPC |
44.94 |
0.2X0.06FPD |
44.94 |
| 0.2X0.2FPE |
44.94 |
0.2X0.2FPA |
44.94 |
| 0.2X0.2FPB |
44.94 |
0.2X0.2FPC |
44.94 |
| 0.2X0.2FPD |
44.94 |
0.2X0.2FPE |
44.94 |
| 0.05X29 |
45.28 |
0.09X29 |
45.27 |
| 0.2X29 |
45.30 |
31X0.05NDA |
45.27 |
| 31X0.05NDB |
45.28 |
31X0.05NDC |
45.28 |
| 0.3X0.05ND |
44.95 |
0.2X0.05ND |
44.94 |
| 0.05X31NDB |
45.26 |
0.05X31NDA |
45.29 |
| 52X0.05F1 |
46.55 |
52X0.05F2 |
44.00 |
| 52X0.1F1 |
46.28 |
52X0.1F2 |
43.73 |
| 52X0.2F1 |
46.30 |
52X0.2F2 |
43.74 |
| 52X0.5F1 |
46.65 |
52X0.5F2 |
44.10 |
| 52X2F1 |
46.31 |
52X2F2 |
43.75 |