Coordinated parallel observations with JWST allow for additional dithers optimized for the coordinated parallel pairing. This article provides a list of those dithers available in the Astronomer’s Proposal Tool (APT).

Dither tables

This page shows dither options available in APT. For full dither offset (as well as pixel offset) see Coordinated Parallel Dither Tables.

The dither offsets are also maintained in the PRD in the following files:

MiriCompromiseDithers.txt (link to PRD)

NircamImagingCompromiseSubpixel.txt (link to PRD)

NirissCompromiseDithers.txt (link to PRD)

NirspecMosDithers.txt (link to PRD)

MIRI prime

Table 2a. Additional Dithers for Parallel Observations with MIRI Prime

Prime + Parallel	Parameter	Values
MIRI Imaging + NIRCam Imaging	Dither Type	standard values
		2-POINT-MIRI-F770W-WITH-NIRCam 3-POINT-MIRI-F770W-WITH-NIRCam 4-POINT-MIRI-F770W-WITH-NIRCam 9-POINT-MIRI-F770W-WITH-NIRCam
		3-POINT-MIRI-F1000W-WITH-NIRCam 4-POINT-MIRI-F1000W-WITH-NIRCam
		2-POINT-MIRI-F1280W-WITH-NIRCam 3-POINT-MIRI-F1280W-WITH-NIRCam 4-POINT-MIRI-F1280W-WITH-NIRCam 9-POINT-MIRI-F1280W-WITH-NIRCam
		2-POINT-MIRI-F1500W-WITH-NIRCam 3-POINT-MIRI-F1500W-WITH-NIRCam 4-POINT-MIRI-F1500W-WITH-NIRCam 9-POINT-MIRI-F1500W-WITH-NIRCam
		2-POINT-MIRI-F1800W-WITH-NIRCam 3-POINT-MIRI-F1800W-WITH-NIRCam 4-POINT-MIRI-F1800W-WITH-NIRCam
		2-POINT-MIRI-F2100W-WITH-NIRCam 3-POINT-MIRI-F2100W-WITH-NIRCam 4-POINT-MIRI-F2100W-WITH-NIRCam 9-POINT-MIRI-F2100W-WITH-NIRCam
		2-POINT-MIRI-F2550W-WITH-NIRCam 3-POINT-MIRI-F2550W-WITH-NIRCam 4-POINT-MIRI-F2550W-WITH-NIRCam 9-POINT-MIRI-F2550W-WITH-NIRCam

MIRI Imaging + NIRISS WFSS	Dither Type	standard values
		2-POINT-MIRI-F560W-WITH-NIRISS
		3-POINT-MIRI-F770W-WITH-NIRISS 4-POINT-MIRI-F770W-WITH-NIRISS 9-POINT-MIRI-F770W-WITH-NIRISS
		3-POINT-MIRI-F1000W-WITH-NIRISS 4-POINT-MIRI-F1000W-WITH-NIRISS 9-POINT-MIRI-F1000W-WITH-NIRISS
		2-POINT-MIRI-F1280W-WITH-NIRISS 3-POINT-MIRI-F1280W-WITH-NIRISS 4-POINT-MIRI-F1280W-WITH-NIRISS 9-POINT-MIRI-F1280W-WITH-NIRISS
		3-POINT-MIRI-F1500W-WITH-NIRISS 4-POINT-MIRI-F1500W-WITH-NIRISS
		2-POINT-MIRI-F1800W-WITH-NIRISS 3-POINT-MIRI-F1800W-WITH-NIRISS 4-POINT-MIRI-F1800W-WITH-NIRISS 9-POINT-MIRI-F1800W-WITH-NIRISS
		2-POINT-MIRI-F2100W-WITH-NIRISS 3-POINT-MIRI-F2100W-WITH-NIRISS 4-POINT-MIRI-F2100W-WITH-NIRISS
		2-POINT-MIRI-F2550W-WITH-NIRISS 3-POINT-MIRI-F2550W-WITH-NIRISS 4-POINT-MIRI-F2550W-WITH-NIRISS 9-POINT-MIRI-F2550W-WITH-NIRISS

NIRCam prime

Table 2b. Additional Dithers for Parallel Observations with NIRCam Prime

Prime + Parallel	Parameter	Values
NIRCam Imaging + MIRI Imaging	Subpixel Dither Type	NIRCam Only
		3-POINT-WITH-MIRI-F560W 4-POINT-WITH-MIRI-F560W
		2-POINT-WITH-MIRI-F770W 3-POINT-WITH-MIRI-F770W 4-POINT-WITH-MIRI-F770W 9-POINT-WITH-MIRI-F770W
		2-POINT-WITH-MIRI-F1000W 3-POINT-WITH-MIRI-F1000W 4-POINT-WITH-MIRI-F1000W 9-POINT-WITH-MIRI-F1000W
		2-POINT-WITH-MIRI-F1280W 3-POINT-WITH-MIRI-F1280W 4-POINT-WITH-MIRI-F1280W
		2-POINT-WITH-MIRI-F1500W 3-POINT-WITH-MIRI-F1500W 4-POINT-WITH-MIRI-F1500W 9-POINT-WITH-MIRI-F1500W
		2-POINT-WITH-MIRI-F1800W 3-POINT-WITH-MIRI-F1800W 4-POINT-WITH-MIRI-F1800W 9-POINT-WITH-MIRI-F1800W
		2-POINT-WITH-MIRI-F2100W 3-POINT-WITH-MIRI-F2100W 4-POINT-WITH-MIRI-F2100W 9-POINT-WITH-MIRI-F2100W
		2-POINT-WITH-MIRI-F2550W 3-POINT-WITH-MIRI-F2550W 4-POINT-WITH-MIRI-F2550W
	NIRCAM Positions (only appears for choice NIRCam Only)	standard values
NIRCam Imaging + NIRISS Imaging	Subpixel Dither Type	NIRCam Only
		2-POINT-LARGE-WITH-NIRISS 2-POINT-MEDIUM-WITH-NIRISS
		3-POINT-LARGE-WITH-NIRISS 3-POINT-MEDIUM-WITH-NIRISS 3-POINT-SMALL-WITH-NIRISS
		4-POINT-LARGE-WITH-NIRISS 4-POINT-MEDIUM-WITH-NIRISS 4-POINT-SMALL-WITH-NIRISS
		9-POINT-LARGE-WITH-NIRISS 9-POINT-MEDIUM-WITH-NIRISS
	NIRCAM Positions (only appears for choice NIRCam Only)	standard values
NIRCam Imaging + NIRISS WFSS	Subpixel Dither Type	NIRCam Only
		2-POINT-LARGE-WITH-NIRISS 2-POINT-MEDIUM-WITH-NIRISS
		3-POINT-LARGE-WITH-NIRISS 3-POINT-MEDIUM-WITH-NIRISS 3-POINT-SMALL-WITH-NIRISS
		4-POINT-LARGE-WITH-NIRISS 4-POINT-MEDIUM-WITH-NIRISS 4-POINT-SMALL-WITH-NIRISS
		9-POINT-LARGE-WITH-NIRISS 9-POINT-MEDIUM-WITH-NIRISS
	NIRCAM Positions (only appears for choice NIRCam Only)	standard values
NIRCam WFSS + NIRISS Imaging	Subpixel Dither Type	4-POINT 9-POINT NONE
		2-POINT-LARGE-WITH-NIRISS 2-POINT-MEDIUM-WITH-NIRISS
		3-POINT-LARGE-WITH-NIRISS 3-POINT-MEDIUM-WITH-NIRISS 3-POINT-SMALL-WITH-NIRISS
		4-POINT-LARGE-WITH-NIRISS 4-POINT-MEDIUM-WITH-NIRISS 4-POINT-SMALL-WITH-NIRISS
		9-POINT-LARGE-WITH-NIRISS 9-POINT-MEDIUM-WITH-NIRISS
NIRCam WFSS + MIRI Imaging	Subpixel Dither Type	4-POINT 9-POINT NONE
		3-POINT-WITH-MIRI-F560W 4-POINT-WITH-MIRI-F560W
		2-POINT-WITH-MIRI-F770W 3-POINT-WITH-MIRI-F770W 4-POINT-WITH-MIRI-F770W 9-POINT-WITH-MIRI-F770W
		2-POINT-WITH-MIRI-F1000W 3-POINT-WITH-MIRI-F1000W 4-POINT-WITH-MIRI-F1000W 9-POINT-WITH-MIRI-F1000W
		2-POINT-WITH-MIRI-F1280W 3-POINT-WITH-MIRI-F1280W 4-POINT-WITH-MIRI-F1280W
		2-POINT-WITH-MIRI-F1500W 3-POINT-WITH-MIRI-F1500W 4-POINT-WITH-MIRI-F1500W 9-POINT-WITH-MIRI-F1500W
		2-POINT-WITH-MIRI-F1800W 3-POINT-WITH-MIRI-F1800W 4-POINT-WITH-MIRI-F1800W 9-POINT-WITH-MIRI-F1800W
		2-POINT-WITH-MIRI-F2100W 3-POINT-WITH-MIRI-F2100W 4-POINT-WITH-MIRI-F2100W 9-POINT-WITH-MIRI-F2100W
		2-POINT-WITH-MIRI-F2550W 3-POINT-WITH-MIRI-F2550W 4-POINT-WITH-MIRI-F2550W

NIRSpec prime

Table 2c. Additional Dithers for Parallel Observations with NIRSpec Prime

Prime + Parallel	Parameter	Values
NIRSpec MOS + NIRCam Imaging	Dither Type	NONE
		2-POINT-WITH-NIRCam-SIZE1 2-POINT-WITH-NIRCam-SIZE2 2-POINT-WITH-NIRCam-SIZE3
		3-POINT-WITH-NIRCam-SIZE1 3-POINT-WITH-NIRCam-SIZE2 3-POINT-WITH-NIRCam-SIZE3

NIRISS prime

Offset values for NIRISS additional dithers are specified in the PRD table NirissCompromiseDithers, and are described in Coordinated Parallel Dither Tables.

Table 2d. Additional Dithers for Parallel Observations with NIRISS Prime

Prime + Parallel	Parameter	Values
NIRISS WFSS + MIRI Imaging	Dither	2-POINT-MIRI-F560W 3-POINT-MIRI-F560W
		3-POINT-MIRI-F770W 9-POINT-MIRI-F770W
		2-POINT-MIRI-F1000W 3-POINT-MIRI-F1000W 4-POINT-MIRI-F1000W
		2-POINT-MIRI-F1280W 3-POINT-MIRI-F1280W 4-POINT-MIRI-F1280W 9-POINT-MIRI-F1280W
		2-POINT-MIRI-F1500W 3-POINT-MIRI-F1500W 4-POINT-MIRI-F1500W 9-POINT-MIRI-F1500W
		2-POINT-MIRI-F1800W 3-POINT-MIRI-F1800W 4-POINT-MIRI-F1800W 9-POINT-MIRI-F1800W
		2-POINT-MIRI-F2100W 3-POINT-MIRI-F2100W 4-POINT-MIRI-F2100W 9-POINT-MIRI-F2100W
		2-POINT-MIRI-F2550W 3-POINT-MIRI-F2550W 4-POINT-MIRI-F2550W 9-POINT-MIRI-F2550W
		standard values
NIRISS WFSS + NIRCam Imaging	Dither	2-POINT-LARGE-WITH-NIRCam 2-POINT-MEDIUM-WITH-NIRCam
		3-POINT-LARGE-WITH-NIRCam 3-POINT-MEDIUM-WITH-NIRCam 3-POINT-SMALL-WITH-NIRCam
		4-POINT-LARGE-WITH-NIRCam 4-POINT-MEDIUM-WITH-NIRCam 4-POINT-SMALL-WITH-NIRCam
		9-POINT-LARGE-WITH-NIRCam 9-POINT-MEDIUM-WITH-NIRCam 9-POINT-MEDIUM-WITH-NIRCam
		standard values

Change log

JWST Proposal Parameters

Additional Dithers for Coordinated Parallel Observations