12 citations · 16 across the 3 of their papers we have counts for
5 papers
Automated Sunspot Detection as an Alternative to Visual Observations
Yoichiro Hanaoka
We developed an automated method for sunspot detection using digital white-light solar images to achieve a performance similar to that of visual drawing observations in sunspot cou…
Internetwork Magnetic Fields Seen in Fe I 1564.8 nm
Yoichiro Hanaoka, Takashi Sakurai
We studied the properties of internetwork magnetic fields in the solar photosphere taking advantage of full-disk Stokes maps of the \ion{Fe}{1} 1564.8 nm line, which were obt…
Synoptic solar observations of the Solar Flare Telescope focusing on space weather
Yoichiro Hanaoka, Takashi Sakurai, Ken'ichi Otsuji +2
The solar group at the National Astronomical Observatory of Japan is conducting synoptic solar observations with the Solar Flare Telescope. While it is a part of a long-term solar…
Infrequent Occurrence of Significant Linear Polarization in H Solar Flares
Tomoko Kawate, Yoichiro Hanaoka
We performed statistical and event studies of linear polarization in the H line during solar flares. The statistical study revealed that, among 71 H flares analyzed, includin…
Solar Coronal Jets Extending to High Altitudes Observed During the 2017 August 21 Total Eclipse
Yoichiro Hanaoka, Ryuichi Hasuo, Tsukasa Hirose +11
Coronal jets, which extend from the solar surface to beyond 2 , were observed in the polar coronal hole regions during the total solar eclipse on 2017 August 21. In a time…