Since 2014, NASA's K2 mission has used the Kepler space telescope to perform high-precision photometry of tens of thousands of stars and galaxies along the ecliptic in "Campaigns" lasting between 65 and 80 days. Most Campaigns were executed in the "backward facing" direction, where the spacecraft was pointed roughly away from Earth. The advantage of this orientation, given Kepler's Earth-trailing orbit, is that Earth never crosses the field of view during a Campaign. However, in this orientation, the Campaign's field of view is only visible from the ground during twilight. K2's 16th and 17th Campaigns were in the "forward facing" orientation to facilitate contemporaneous observations from Earth-based facilities over the entire duration of the campaigns. Numerous investigations executed during C16 and C17 were designed to specifically take advantage of the ability to simultaneously obtain complementary observations of K2 targets. PanSTARRS1 ("PS1") monitored these fields during the K2 campaigns in multiple filters. The primary motivation was to identify supernovae in the K2 fields rapidly enough to enable follow-up observations. Transients were identified by the PanSTARRS Transient Science Server within 12-24 hours of observations. Alerts were released via the Transient Name Server. The PS1 K2 supernova survey data are released here as a MAST HLSP. Please refer to the AAS Research Note (Dotson et al. 2018) for more information and relevant references to the PanSTARRS data, observations, processing, and survey strategies. You can refer to the full collection of K2SNE data products using the DOI http://dx.doi.org/10.17909/T9CM3C.
Each cluster is organized into subdirectories based on the PS1 tessellation pattern, which is identical to the one used by the main PS1 survey. Each tessellation has multiple files with the following syntax:
<skycellnum> = footprint identifier (e.g., "1014.030"), the first number is the "projection cell ID", the second number is the "skycell" indicating which part of the 10x10 grid this warp represents (1st number always 0, 2nd number is y-index, 3rd number is x-index), see the PS1 Tessellation Pattern Page for more info
<mjd> = Modified Julian Date of start of observation (e.g., "58220.420013")
<filt> = the filter used, one of "g", "r", "i", or "z"
<exteng> = file extension, which correspond to one of the following:
cmf.fits: camera-stage catalog file
log.txt: processing log file
mask.fits: mask file
mdl.fits: background model for the warp skycell image made up from the chip background models on a finer interpolated grid of the chip(s) that are remapped into the warp skycell image, it contains the background samples that can be interpolated to reconstruct the smooth background model that was subtracted from the science images