An Image Processing approach to identify solar plages observed at 393.37 nm by Kodaikanal Solar Observatory

Sarvesh Gharat and Bhaskar Bose

Submitted on 21 September 2022


Solar Plages are bright chromospheric features observed in Ca II K photographic observations of the sun. These are regions of high magnetic field concentration thus tracer of magnetic activity of the Sun and are one of the most important features to study long-term variability of the Sun as Ca II K spectroheliograms are recorded for more than a century. . However, detection of the plages from century-long databases is a non-trivial task and need significant human resources for doing it manually. Hence, in this study, we propose an image processing algorithm that can identify solar plages from Ca II K photographic observations. The proposed study has been implemented on archival data from Kodaikanal Solar Observatory. To ensure that the algorithm works, irrespective of noise level, brightness, and other image properties, we randomly draw a sample of images from the data archive to test our algorithm.


Comment: Output data will be made available on request after 2 years of publication

Subjects: Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Instrumentation and Methods for Astrophysics; Computer Science - Computer Vision and Pattern Recognition