Table 3.
Approximate offsets for the centers of the off-axis fields (OAF).
| Field | Offset in pixels | Offset in arcsec | On sky | ||
|---|---|---|---|---|---|
| Δx | Δy | Δα | Δδ | ||
| Center | 0 | 0 | 0 | 0 | |
| OAF1 | 0 | −715 | 0.00″ | −2.57″ | S |
| OAF2 | −715 | −428 | +2.57″ | −1.54″ | E-SE |
| OAF3 | −715 | 0 | +2.57″ | 0.00″ | E |
| OAF4 | −715 | +428 | +2.57″ | +1.54″ | E-NE |
| OAF5 | 0 | +715 | 0.00″ | +2.57″ | N |
| OAF6 | +715 | +428 | −2.57″ | +1.54″ | W-NW |
| OAF7 | +715 | 0 | −2.57″ | 0.00″ | W |
| OAF8 | +715 | −428 | −2.57″ | −1.54″ | W-SW |
Notes. Pixel offsets Δx and Δy refer to preprocessed images with image flips applied to cam1 and cam2 images. Columns 4–6 give the on-sky offsets for the right ascension Δα and declination Δδ for field stabilized observations taken without field position angle offset as shown in Fig. 3. The actual offsets deviate by about ±3 pixels or ±0.01″ from the given design values.
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