scholarly journals On the spectroscopy of auroral green line radiation

1930 ◽  
Vol 129 (809) ◽  
pp. 31-43 ◽  
Keyword(s):  
High Light ◽  
Green Line ◽  
Light Power ◽  
Line Radiation ◽  
Moonless Night ◽  
Night Sky

In a recent paper by the authors on “Spectroscopy of the Light from the Night Sky,” a description was given of the development and the construction, with optical details, of a high light power spectrograph suitable for photographing the spectrum of the light of the moonless night sky and the spectra of auroral displays. Preliminary experiments were carried out with this instrument in England and in Canada, and a considerable number of spectrograms recorded with the instrument were reproduced and included in the paper.

SPECTROSCOPY OF THE LIGHT FROM THE NIGHT SKY

1930 ◽  
Vol 2 (4) ◽  
pp. 279-290 ◽  
Author(s):  
J. C. McLennan F.R.S. ◽  
H. J. C. Ireton M.A.
Keyword(s):  
High Light ◽  
Light Power ◽  
Moonless Night ◽  
Night Sky ◽  
Auroral Phenomena

This paper describes the development and the construction, with optical details, of a high light power spectrograph suitable for the photography of the spectrum of the light of the moonless night sky and the spectra of auroral displays.Preliminary experiments carried out with it in England and in Canada are described. Typical spectrograms recorded by the instrument are shown.Suggestions for still further increasing the efficiency of the spectrograph are made. The advantages of using the spectrograph described are pointed out. Additional investigations of auroral phenomena, and an extension of those previously made are outlined.

scholarly journals The aurora line in the spectrum of the night sky

1922 ◽  
Vol 100 (705) ◽  
pp. 367-378 ◽  
Keyword(s):  
Wave Length ◽  
Unknown Origin ◽  
Green Line ◽  
Aurora Borealis ◽  
Low Latitudes ◽  
Good Measurement ◽  
Night Sky

Several observers have found that the green line of unknown origin seen in the Aurora Borealis can also be seen in the sky on ordinary nights, and in comparatively low latitudes. Slipher, in particular, has studied the line photographically, and has succeeded in recording it with a three-prism spectrograph of 15 inches focus, thus obtaining a good measurement of the wave-length.

scholarly journals II.—Bright Clouds on a Dark Night Sky

1883 ◽  
Vol 32 (1) ◽  
pp. 11-36 ◽  
Author(s):  
C. Piazzi Smyth
Keyword(s):  
Small Extent ◽  
Large Telescope ◽  
Dark Night ◽  
Moonless Night ◽  
Night Sky

On a moonless night, whenever clouds of an ordinary elevation in the atmosphere appear upon, or pass across, the star-spangled sky behind them, they exhibit themselves, as a rule, dark, sometimes even black, in comparison therewith. And no wonder, when every part of the open sky from visible star to visible star therein must be lit up to some, though doubtless a very small, extent by the faintest general and cumulative radiance of those myriads and myriads of lesser stars, which only a large telescope can show to be individually existent as actual stellar points of light, but in their aggregate more nearly eternal, and still more constant from age to age, than our gigantic Sun itself.

scholarly journals A study of the presence or absence of nitrogen bands in the auroral spectrum

1922 ◽  
Vol 101 (711) ◽  
pp. 312-315 ◽  
Keyword(s):  
Magnetic Disturbance ◽  
Green Line ◽  
The South ◽  
Meteorological Observatory ◽  
Night Sky

In a previous paper I showed that the negative, bands of nitrogen were actually stronger than the green aurora line on the occasion of the auroral display of May 13-14, 1921, which was a typical aurora, in the sense that it was accompanied by conspicuous solar and magnetic disturbance. In contrast with this, the nitrogen bands were not observed at all in the numerous photographs which showed the green line in the night sky on ordinary nights in the south of England. The point deserved much closer scrutiny, as it might be expected to throw light on whether the ordinary night sky effect was to be classed with the northern lights or not. To get additional evidence, I proceeded to Shetland in mid-October, 1921. Dr. G. C. Simpson, F. R. S., and Dr. A. Crichton Mitchell very kindly gave me facilities for working at the meteorological observatory near Lerwick, and Mr. J. Crichton, the officer in charge, did everything possible to help, and continued the exposures throughout the winter after 1 had left. Indeed, all the most successful photographs were taken by him, and forwarded to me for discussion.

scholarly journals High-efficiency optogenetic silencing with soma-targeted anion-conducting channelrhodopsins

2017 ◽  
Author(s):  
Mathias Mahn ◽  
Lihi Gibor ◽  
Katayun Cohen-Kashi Malina ◽  
Pritish Patil ◽  
Yoav Printz ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
High Efficiency ◽  
Single Channel ◽  
Ion Homeostasis ◽  
Reversal Potential ◽  
High Light ◽  
Mammalian Brain ◽  
Membrane Targeting ◽  
Power Requirement ◽  
Light Power

AbstractOptogenetic silencing allows time-resolved functional interrogation of defined neuronal populations. However, the limitations of inhibitory optogenetic tools impose stringent constraints on experimental paradigms. The high light power requirement of light-driven ion pumps and their effects on intracellular ion homeostasis pose unique challenges, particularly in experiments that demand inhibition of a widespread neuronal population in vivo. Guillardia theta anion-conducting channelrhodopsins (GtACRs) are promising in this regard, due to their high single-channel conductance and favorable photon-ion stoichiometry. However, GtACRs show poor membrane targeting in mammalian cells, and the activity of such channels can cause transient excitation in the axon due to an excitatory chloride reversal potential in this compartment. Here we address both problems by enhancing membrane targeting and subcellular compartmentalization of GtACRs. The resulting GtACR-based optogenetic tools show improved photocurrents, greatly reduced axonal excitation, high light sensitivity and rapid kinetics, allowing highly efficient inhibition of neuronal activity in the mammalian brain.

scholarly journals Absolute intensity of the aurora line in the night sky, and the number of atomic transitions required to maintain it

1930 ◽  
Vol 129 (811) ◽  
pp. 458-467 ◽  
Keyword(s):  
Continuous Spectrum ◽  
Angular Size ◽  
Absolute Intensity ◽  
High Accuracy ◽  
Resolving Power ◽  
Green Line ◽  
Atomic Transitions ◽  
Absolute Determination ◽  
Night Sky

Some time ago Prof. S. Chapman, F. R. S., pressed upon me the importance of making an absolute determination of the intensity of the auroral green line in the night sky, in order to fix the number of atomic transistions per second required to maintain it. Such a determination will be of value even if not of high accuracy value, high accuracy is out of the question. The difficulty of the problem arises from the faintness of the light of the auroral line, and the fact that it is not isolated but superposed on a background of apparently continuous spectrum, from which it cannot in the nature of the case be completely separated without the use of high spectroscopic resolving power. The last usually involves loss of light and restriction of the angular size of the photometric field. There is too little light to begin with to allow of this.

Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

2000 ◽  
Vol 179 ◽  
pp. 201-204
Author(s):  
Vojtech Rušin ◽  
Milan Minarovjech ◽  
Milan Rybanský
Keyword(s):  
Emission Lines ◽  
High Latitudes ◽  
Green Line ◽  
Solar Cycles ◽  
The South ◽  
Coronal Emission ◽  
Local Maxima ◽  
The North ◽  
Cyclic Variations

AbstractLong-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18–23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

Periodic Variations in the Coronal Green Line Intensity and their Connection with the White-light Coronal Structures

2000 ◽  
Vol 179 ◽  
pp. 197-200
Author(s):  
Milan Minarovjech ◽  
Milan Rybanský ◽  
Vojtech Rušin
Keyword(s):  
Time Resolution ◽  
White Light ◽  
Short Time Scale ◽  
High Time Resolution ◽  
Green Line ◽  
Periodic Intensity ◽  
Coronal Green Line ◽  
Significant Intensity ◽  
Short Time ◽  
Coronal Structures

AbstractWe present an analysis of short time-scale intensity variations in the coronal green line as obtained with high time resolution observations. The observed data can be divided into two groups. The first one shows periodic intensity variations with a period of 5 min. the second one does not show any significant intensity variations. We studied the relation between regions of coronal intensity oscillations and the shape of white-light coronal structures. We found that the coronal green-line oscillations occur mainly in regions where open white-light coronal structures are located.

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