For a detailed Finder Chart and rotation setting see Kyle Kaplan's software. For rough rotations use the lookup table below.
393 = Default Encoder Setting at 90 deg. PA (slit east to west)
Position Angle (Start north and go east, N=0, E=90, S=180, W=270 degrees, Default = 90 deg slit oriented east-west)
(Encoder Setting) = 393 - 90 + (Position Angle) = 303 + (Position Angle)
Encoder should not go further than +/- 180 degrees from the nominal 90 degree position to avoid entangling wires
| Positon Angle | Encoder Setting |
|---|---|
| 360, 0 | 303 |
| 15 | 318 |
| 30 | 333 |
| 45 | 348 |
| 60 | 363 |
| 75 | 378 |
| 90 | 393 |
| 105 | 408 |
| 120 | 423 |
135 | 438 |
| 150 | 453 |
| 165 | 468 |
| 180 | 483 |
| 195 | 498 |
| 210 | 513 |
| 225 | 528 |
| 240 | 543 |
| 255 | 558 |
270 | 573 |
| 285 | 228 |
| 300 | 243 |
| 315 | 258 |
| 330 | 273 |
| 345 | 288 |
For a 10,000K A0V star with H-K=0, the IGRINS Exposure Time Calculator (Version 2.11) gives the following estimates.
| Magnitude | Exposure Time | SNR |
|---|---|---|
| 1 | ||
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| 15 | ||