Measurements and predictions of the illuminance during a solar eclipse

Möllmann, Klaus‐Peter; Vollmer, Michael

doi:10.1088/0143-0807/27/6/004

Cited by 34 publications

(20 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The chosen linear gradient is a rough, though astonishingly accurate, approximation for most of the partial phase of the eclipse [9]. In order to compute radiance as a function of time, we used the known moon´s shadow velocity during the 2017 eclipse in Idaho of about v=839 m/s.…”

Section: Simplified Model For Visual Rangesmentioning

confidence: 99%

Extended visual range: an observation during a total solar eclipse

Vollmer

Shaw

2019

Fifteenth Conference on Education and Training in Optics and Photonics: ETOP 2019

Self Cite

View full text Add to dashboard Cite

Solar eclipses are magnificent natural phenomena during which the sun is obscured by the moon. Besides the unique opportunity of studying the solar corona and immediate vicinity of the sun, an eclipse also leads to a darkened daytime sky with sunset colors and many other fascinating phenomena. Here we focus on how the daytime horizontal visual range changed during the duration of the solar eclipse of 21 August 2017, observed from Rexburg, Idaho, USA. Close to totality the eastern horizon for a short time period showed the contours of the Grand Teton Mountains from distances between about 80 km to 90 km. We show and discuss photographic images that show the visual range during totality being significantly extended beyond the visual range in most of the partial phase before and after totality, which was below 80 km when the mountains could not be seen by the naked eye. This phenomenon of an extended visual range can be explained in terms of a simple model for the daytime visual range. This model, which will be explained in this presentation, nicely reproduces the observations and also predicts other phenomena; for example, it predicts that similar phenomena may be observed if part of the line of sight close to the observer is in deep shade of a thick cloud cover. The presentation will tie these observations and their explanation to the teaching of optical scattering and atmospheric optics.

show abstract

Section: Simplified Model For Visual Rangesmentioning

confidence: 99%

Extended visual range: an observation during a total solar eclipse

Vollmer

Shaw

2019

Fifteenth Conference on Education and Training in Optics and Photonics: ETOP 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…A very good comprehensible derivation of these formulas is given by Möllman and Vollmer (). Here d is the angular distance between the centers of solar and lunar disk and is the critical parameter since the other geometrical variables depend on it.…”

Section: The Occultation and Obscuration Functionsmentioning

confidence: 99%

Cloudiness and Solar Radiation During the Longest Total Solar Eclipse of the 21st Century at Tianhuangping (Zhejiang), China

Peñaloza-Murillo

Pasachoff

2018

JGR Atmospheres

View full text Add to dashboard Cite

The lack of comprehensive solar radiation monitoring during the longest total solar eclipse of the 21st century at Tianhuangping (Zhejiang), China, on 22 July 2009, has led to this investigation in order to evaluate the cloudiness contribution in estimating the impact on global solar radiation throughout this phenomenon. In doing so, we applied a cloud cover empirical model to obtain the global solar radiation and, at the same time, we deduced a theoretical model to get the direct solar radiation in which both the occultation and obscuration functions of this eclipse are included. We took limb darkening and atmospheric transmission into account. Though the weather during our eclipse observations agreed with the forecasts for that day, clouds and some rain, we were nonetheless able to observe all phases of the eclipse from our observation site at Tianhuangping. This experience suggests that for coming eclipses a record of the in situ observation protocol of cloudiness is mandatory. Our results for comparing global solar radiation models indicate that our total solar eclipse radiation model is quite acceptable and representative of that which could have happened at that time.Plain Language Summary A total solar eclipse is a situation where the Sun is obscured by the Moon viewed from Earth. In this particular arrangement in space a shadow is cast over a particular region. Thus, the ideal circumstances to observe a total solar eclipse are those in which the sky is cloudless in that region or zone. Yet from time to time this phenomenon occurs in the presence of interfering clouds preventing a direct observation of the event. However, under these adverse circumstances effects over the environment can still be felt and measured as, for example, the rapid reduction of solar energy reaching the surface. In that case such measurements would be lacking, but with some information about cloudiness one can have an idea of how the variation of this energy during the eclipse took place. In the procedure a quantitative knowledge of how the Moon disk is going to progressively cut the Sun's brightness during the eclipse is necessary. From an environmental point of view it is shown that a scientific observation of a total solar eclipse matters even though it was made under the influence of blocking clouds.

show abstract

“…The obscuration of the Sun, which is the fraction of the surface area of the solar disc that is hidden by the Moon (and hence governs the attenuation of the light of the Sun), lags a bit behind in the beginning of the partial phase: after a half hour from the first contact the magnitude of the eclipse is already 0.4, but the obscuration only 29%. After this it accelerates: in the remaining 50 min to totality the obscuration increases almost linearly with the eclipse magnitude and hence with time [13]. See Table 1, in which the Sun's photometric brightness is calculated as a function of eclipse magnitude for a typical eclipse (ratio lunar/solar disk diameter 1.04).…”

Section: A Eclipse Timelinementioning

confidence: 99%

Visibility of stars, halos, and rainbows during solar eclipses

Können¹,

Hinz

2008

Appl. Opt.

View full text Add to dashboard Cite

The visibility of stars, planets, diffraction coronas, halos, and rainbows during the partial and total phases of a solar eclipse is studied. The limiting magnitude during various stages of the partial phase is presented. The sky radiance during totality with respect to noneclipse conditions is revisited and found to be typically 1/4000. The corresponding limiting magnitude is +3.5. At totality, the signal-to-background ratio of diffraction coronas, halos, and rainbows has dropped by a factor of 250. It is found that diffraction coronas around the totally eclipsed Sun may nevertheless occur. Analyses of lunar halo observations during twilight indicate that bright halo displays may also persist during totality. Rainbows during totality seem impossible.

show abstract

Measurements and predictions of the illuminance during a solar eclipse

Cited by 34 publications

References 15 publications

Extended visual range: an observation during a total solar eclipse

Extended visual range: an observation during a total solar eclipse

Cloudiness and Solar Radiation During the Longest Total Solar Eclipse of the 21st Century at Tianhuangping (Zhejiang), China

Visibility of stars, halos, and rainbows during solar eclipses

Contact Info

Product

Resources

About