Starfield Removal

Stellar light visible in PUNCH observations can be characterized and removed once the data has been processed and projected into the same frame.

Concept

By gathering observations and projecting the data into a common celestial frame, the starfield signal can be gathered and estimated. For a given observation in the helioprojective frame, this map of stellar signal can be projected back and subtracted, revealing the desired coronal component of the input signal.

Applying correction

Image resampling is carried out in the punchbowl.level3.stellar.subtract_starfield_background_task function:

punchbowl.level3.stellar.subtract_starfield_background_task(data_object: NDCube, starfield_background_path: str | None) → NDCube

Subtracts a background starfield from an input data frame.

checks the dimensions of input data frame and background starfield match and subtracts the background starfield from the data frame of interest.

Parameters:

• data_object (NDCube) – A NDCube data frame to be background subtracted

• starfield_background_path (str) – path to a NDCube background starfield map

Returns:

A background starfield subtracted data frame

Return type:

NDCube

If you wish to incorporate this as a Prefect task in a custom pipeline, using something like the punchbowl.level3.stellar.subtract_starfield_background_task is recommended.

Deriving starfield model

Starfield models are generated from data using the remove_starfield package, where further documentation can be found.