查看“Sky”的源代码

[https://www.sdss3.org/dr10/algorithms/sky.php] 
*(the "PSP" sky): These include an initial estimate of the sky in each field , the photo sky estimates that were applied to the fluxmeasurements of the catalog.
*"global sky""  a new estimate of the sky calculated in postprocessing that is included in the [[corrected frame]]s.