91 citations · 177 across the 5 of their papers we have counts for
5 papers
Re-calibration of the Sunspot Number: Status Report
F. Clette, L. Lefèvre, T. Chatzistergos +18
We report progress on the ongoing recalibration of the Wolf sunspot number (SN) and Group sunspot number (GN) following the release of version 2.0 of SN in 2015. This report consti…
Reconstructing solar magnetic fields from historical observations V. Sunspot magnetic field measurements at Mount Wilson Observatory
Alexei A. Pevtsov, Kseniya A. Tlatova, Alexander A. Pevtsov +7
Context. Systematic observations of magnetic field strength and polarity in sunspots began at Mount Wilson Observatory (MWO), USA in early 1917. Except for a few brief interruption…
The effect of telescope aperture, scattered light, and human vision on early measurements of sunspot and group numbers
Nina V. Karachik, Alexei A. Pevtsov, Yury A. Nagovitsyn
Early telescopic observations of sunspots were conducted with instruments of relatively small aperture. These instruments also suffered from a higher level of scattered light, and…
Tilt of sunspot bipoles in Solar Cycles 15 to 24
Ksenia Tlatova, Andrey Tlatov, Alexei Pevtsov +7
We use recently digitized sunspot drawings from Mount Wilson Observatory to investigate the latitudinal dependence of tilt angles of active regions and its change with solar cycle.…
Properties of Magnetic Neutral Line Gradients and Formation of Filaments
Nina V. Karachik, Alexei A. Pevtsov
We investigate gradient of magnetic field across neutral lines (NLs), and compare their properties for NLs with and without the chromospheric filaments. Our results show that there…