ResourceName
Mauna Loa Solar Observatory K-Coronagraph Polarized Brightness, 15 s Images
AlternateName
MLSO K-Cor pB Images
DOI
https://doi.org/10.5065/d69g5jv8
ReleaseDate
2013-09-30 00:00:00
Description
The calibrated coronal polarizion brightness, pB, fits images are expressed in units of B/Bsun, where Bsun is the brightness of the solar disk. The brightness is produced by photospheric photons that are Thomson scattered by coronal electrons, with the brightness being proportional to the density of coronal electrons along the line-of-sightof the observer. These data are good for determining electron line-of-sight densities and estimating the mass of coronal structures.
Typical pB values of the solar corona in the K-Cor field-of-view (1.05 to 3 solar radii) are 10^-6 to 10^-9 B/Bsun. Images are averaged over 15 s to acquire sufficient signal-to-noise. The pB images have a nominal cadence of 15 s and are also available as 2 min averages and a daily 10 min average image.
Calibration steps include: camera non-linearity correction, dark and gain corrections, polarization demodulation, distortion correction, combining images from two cameras, remove sky polarization, and correction for variations over the day in sky transmission.
Acknowledgement
Courtesy of the Mauna Loa Solar Observatory, operated by the High Altitude Observatory, as part of the National Center for Atmospheric Research (NCAR). NCAR is supported by the National Science Foundation. (http://www2.ucar.edu/terms-of-use)
PublicationInfo
Authors
Burkepile J., and M. Galloy
PublicationDate
2018-03-27 12:34:56
PublishedBy
Mauna Loa Solar Observatory
Funding
Agency
National Science Foundation
Project
MLSO K-Coronagraph
Contacts
Signal to noise floor is 3e-9 B/Bsun (relative intensity to the brightness of the solar disk). Some pixels have negative intensity values which means they are noise dominated and there is no signal. Therefore these negative numbers are not physical values.