Images¶

Images of the sky in the six LSST filters with a variety of calibration levels.

The schema browser includes tables of image metadata (ObsCore).

All image data products are available via the butler, SIA, and TAP services.

The “Butler Dataset type” entry on each image type’s page is of the format (‘datasetTypeName’, {dimension1, dimension2, dimension3}, StorageClass), where dimensions in bold are required dimensions for retrieving datasets of this type. See Butler terminology for more information.

Note

When reading images with the butler, it can be much more efficient to read just the pixels of interest, by passing:

parameters={
    "bbox": lsst.geom.Box2I(
        lsst.geom.Point2I(x1, y1),
        lsst.geom.Point2I(x2, y2),
    )
}

as a keyword argument to butler.get. It is also more efficient to just read the pixel values from a single plane by adding a storage class component name to the dataset type name, e.g.:

butler.get("visit_image.image", ...)

to load just the main image plane, not the mask, variance, or metadata.

Coadd images¶

Combinations of multiple calibrated images of the same region of the sky to achieve greater depth (to detect fainter objects), or for use as templates in difference image analysis.

Visit images¶

Processed and calibrated images from individual visits (single observations).

Visit image

Difference images¶

Created by subtracting a template image from a visit image.

Difference image

Raw exposures¶

The unprocessed images received directly from the camera.

Raw exposure