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IFU_DITHER allows the PI to specify the dithering strategy for their observations, but may alternatively request not to dither their observations, with the understanding that this will not provide full spatial coverage of their requested field. PIs may request the preset -3, 3, 4, 5 and 6-dither patterns. The LIFU preset patterns will be properly rotated according to the position angle of the observation.
IMPORTANT: Exposure options for which fixed dither patterns are available in IFU modes are 3x, 4x, 5x, 6x. |
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For custom dither patterns, constraints on the dither step size are imposed by the WASP to ensure that the guide star remains within the guiding camera field of view. From the perspective of IFU users, careful consideration of the dithering options should be made. Below it's an example of custom dithering. Note that pointings are provided for each dither, rather than the dither pointings from an initial position. The three pointings provided in the example below would be executed as part of one only OB.
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Column | Description | Format | Length | Value(s) | Units | Example |
|---|---|---|---|---|---|---|
TARGPRO | Optional description of programme | ASCII | ≤40 | WS2023B2-010_001 | ||
TARGNAME | The target name | ASCII | ≤30 | M33 | ||
TARGID | The identifier of the target assigned for this programme | ASCII | ≤30 | M33_NE | ||
PROGTEMP | Observing Programme Template | ASCII | 8 (fixed) | 41331.3+ | ||
OBSTEMP | Observing Constraints Template | ASCII | 5 (fixed) | FAACA | ||
GAIA_ID | GAIA Source Identifier | ASCII | 19 | 1463976195968535680 | ||
GAIA_DR | GAIA Data Release version | I1 | 2, 3 | 3 | ||
GAIA_RA | Gaia RA of target | F11.7 | 0...360 | degrees | 178.221875 | |
GAIA_DEC | Gaia Dec of target | F11.7 | -90...90 | degrees | 44.123919 | |
GAIA_EPOCH | Gaia Epoch of target | F6.1 | 2015.5 (DR2), 2016.0 (DR3) | Julian year | 2016.0 | |
GAIA_PMRA | Gaia Proper Motion of target in RA | F11.3 | mas/yr | 12.1 | ||
GAIA_PMDEC | Gaia Proper Motion of target in Dec | F11.3 | mas/yr | 0.01 | ||
GAIA_PARAL | Gaia Parallax of target | F10.3 | mas | 0.002 | ||
IFU_PA_REQUEST | Position Angle of IFU bundle | F11.7 | -180...180 | degrees | 106.701 | |
IFU_DITHER | IFU dither pattern code | I2 | -3, -1, 0, 3, 4, 5, 6 | 3 |
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