Pointing

jwpoint.pointing.calculate_offset(xpoint, ypoint, file, coords='detector')

Calculate the applied offset based on the final pointing position

The offset is always returned in detector coordinates (X-Y) with units of arcseconds.

Parameters:

• xoffset – x pointing position [pixel or arcsec]

• yoffset – y pointing position [pixel or arcsec]

• file (str | Path | JwstDataModel) – File that will be used to get the WCS and derive the offsets.

• coords (str) – Coordinates in which the transofmration is applied internally. This does not change the output coordinates which are always arcsec. Can be "detector" or "v2v3".

• xpoint (float)

• ypoint (float)

Raises:

ValueError – Raised if an invalid coords argument is provided

Return type:

tuple[float, float]

Returns:

The offset applied to the reference position

jwpoint.pointing.get_pointing_position(xoffset, yoffset, file, offset_frame='detector')

Get the pointing position coordinates with an offset applied

The pointing position is always returned in detector coordinates (pixels).

Parameters:

• xoffset (float) – x or V2 offset [arcsec]

• yoffset (float) – y or V3 offset [arcsec]

• file (str | Path | JwstDataModel) – File that will be used to get the WCS and derive the pointing posision

• coords – Coordinates in which the transofmration is applied internally. This does not change the output coordinates which are always pixels. Can be "detector" or "v2v3".

• offset_frame (str)

Raises:

ValueError – Raised if an invalid coords argument is provided

Return type:

tuple[float, float]

Returns:

The pointing detector coordinates in pixels

jwpoint.pointing.long_to_short(x, y, file_lw, file_sw)

Convert position from the long- to short-wavelength channel for NIRCam

The long-wavelenth (LW) X-Y detector position is converted to V2-V3 using the LW file. This is then converted to short-wavelength (SW) X-Y detector position using the SW file.

Parameters:

• x (float) – X position in the LW channel

• y (float) – Y position in the SW channel

• file_lw (str | Path | JwstDataModel) – LW file to use for WCS

• file_sw (str | Path | JwstDataModel) – SW file to use for WCS

Return type:

tuple[float, float]

Returns:

The X and Y positions in SW

jwpoint.pointing.v2v3_to_xy(v2, v3, model)

Convert V2-V3 coordinates to detector position

Parameters:

• v2 (float) – V2 position

• v3 (float) – V3 position

• model (str | Path | JwstDataModel) – File used to define WCS coordinates

Return type:

tuple[float, float]

Returns:

x and y detector coordinates

jwpoint.pointing.xy_to_v2v3(x, y, model)

Convert X-Y detector position to V2-V3

Parameters:

• x (float) – X position in detector coordinates

• y (float) – Y position in detector coordinates

• model (str | Path | JwstDataModel) – File used to define WCS

Return type:

tuple[float, float]

Returns:

V2 and V3 cooordinates