PS1 took approximately 370,000 images from 2010 to 2015. These images are detrended, astrometrically calibrated, resampled (warped) onto a standard sky coordinate grid, stacked, and differenced. The different types of images are described below. More details about image filenames and data formats are included in the description of the PanSTARRS1 Image Cutout Service.
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Raw Images
After an exposure is taken at the telescope, the raw image files of the 60 OTA CCDs (see GPC1 Camera) are corrected for persistence issues and then handed over to the IPP processing (need link to a description) for further analysis. The STScI PS1 Archive does not provide these images.
Camera Images
The camera images are created by detrending the raw images (i.e., masking, bias subtraction, flat fielding), and applying an astrometric and photometric calibration. The STScI PS1 Archive does not provide these images.
Image Artifacts and Anomalies
Warp Images (available in DR2)
Stack Images (DR1)
Difference Images (available in DR3)
Difference images are created by subtracting a warp from another image, in general the stack, after matching the PSFs and normalization using a spatially varying kernel. All static objects such as galaxies and constant stars are subtracted out, and only the excess flux from the different epochs is left. Even though the differences images are not stored on disk, they can be created, and it is planned to make them accessible through the STScI PS1 interface in a later release.
Mask Images
Weight Images
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