Revisiting Kunitomo’s Sunspot Drawings During 1835 – 1836 in Japan

Fujiyama, Masashi; Hayakawa, Hisashi; Iju, Tomoya; Kawai, Toshiki; Toriumi, Shin; Otsuji, Kenichi; Kondo, Katsuya; Watanabe, Y.; Nozawa, Satoshi; Imada, Shinsuke

doi:10.1007/s11207-019-1429-3

Cited by 17 publications

(12 citation statements)

References 86 publications

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“…Additionally, spot areas are to be studied further owing to their seemingly exaggerated size as observed in other historical observations using aerial imaging method (see e.g., Fujiyama et al, 2019;Karachik et al, 2019). Further research on the Dalton minimum will improve our knowledge of solar activity during the solar minima or the suppressed solar cycles.…”

Section: Conclusion and Outlooksmentioning

confidence: 99%

Thaddäus Derfflinger’s Sunspot Observations during 1802–1824: A Primary Reference to Understand the Dalton Minimum

Hayakawa

Besser

Iju

et al. 2020

ApJ

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As we are heading towards the next solar cycle, presumably with a relatively small amplitude, it is of significant interest to reconstruct and describe the past grand minima on the basis of actual observations of the time. The Dalton Minimum is often considered one of the grand minima captured in the coverage of telescopic observations. Nevertheless, the reconstructions of the sunspot group number vary significantly, and the existing butterfly diagrams have a large data gap during the period. This is partially because most long-term observations have remained unexplored in historical archives. Therefore, to improve our understanding on the Dalton Minimum, we have located two series of Thaddäus Derfflinger's observational records (a summary manuscript and logbooks) as well as his Brander's 5.5-feet azimuthal-quadrant preserved in the Kremsmünster Observatory. We have revised the existing Derfflinger's sunspot group number with Waldmeier classification and eliminated all the existing 'spotless days' to remove contaminations from solar meridian Hayakawa et al. (2020) Thaddäus Derfflinger's sunspot observations during

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Section: Conclusion and Outlooksmentioning

confidence: 99%

Thaddäus Derfflinger’s Sunspot Observations during 1802–1824: A Primary Reference to Understand the Dalton Minimum

Hayakawa

Besser

Iju

et al. 2020

ApJ

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“…Kunimoto Toubei observed and recorded sunspots in the form of drawings from Japan from 1835 February 3 to 1836 March 24, with an additional single observation on 1836 September 25 (Fujiyama et al 2019).…”

Section: Other Observers Near the Dalton Minimummentioning

confidence: 99%

Historical sunspot records

Arlt

Vaquero

2020

Living Rev Sol Phys

103

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Sunspot observations are available in fairly good numbers since 1610, after the invention of the telescope. This review is concerned with those sunspot observations of which longer records and drawings in particular are available. Those records bear information beyond the classical sunspot numbers or group sunspot numbers. We begin with a brief summary on naked-eye sunspot observations, in particular those with drawings. They are followed by the records of drawings from 1610 to about 1900. The review is not a compilation of all known historical sunspot information. Some records contributing substantially to the sunspot number time series may therefore be absent. We also glance at the evolution of the understanding of what sunspots actually are, from 1610 to the 19th century. The final part of the review illuminates the physical quantities that can be derived from historical drawings.

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“…In their turn, sunspot area is a much more robust measure than SSN and GN. However, while sunspot areas could be derived even from the very early drawings, they might be a subject of large uncertainties due to different drawing styles, lack of proper scaling, and some may even be unsuitable for a scientific use (e.g., Arlt et al 2016;Senthamizh Pavai et al 2015;Carrasco et al 2018b;Fujiyama et al 2019).…”

Section: Discussionmentioning

confidence: 99%

The effect of telescope aperture, scattered light and human vision on early measurements of sunspot and group numbers

Karachik

Pevtsov

Nagovitsyn

2019

Monthly Notices of the Royal Astronomical Society

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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 the human eye served as a "detector". The eye's ability to resolve small details depends on image contrast, and on average the intensity variations smaller than ≈ 3% contrast relative to background are not detected even if they are resolved by the telescope. Here we study the effect of these three parameters (telescope aperture, scattered light, and detection threshold of human vision) on sunspot number, group number, and area of sunspots. As an "ideal" dataset, we employ white-light (pseudocontinuum) observations from Helioseismic and Magnetic Imager (HMI) onboard of Solar Dynamics Observatory, and we model the appearance of sunspots by degrading the HMI images to corresponding telescope apertures with an added scattered light. We discuss the effects of different parameters on sunspot counts and derive functional dependencies, which could be used to normalize historical observations of sunspot counts to common denominator.

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Revisiting Kunitomo’s Sunspot Drawings During 1835 – 1836 in Japan

Cited by 17 publications

References 86 publications

Thaddäus Derfflinger’s Sunspot Observations during 1802–1824: A Primary Reference to Understand the Dalton Minimum

Thaddäus Derfflinger’s Sunspot Observations during 1802–1824: A Primary Reference to Understand the Dalton Minimum

Historical sunspot records

The effect of telescope aperture, scattered light and human vision on early measurements of sunspot and group numbers

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