A test of the electromagnetic theory of the hydrogen vortices surrounding sun-spots

The extensive fields of force shown by the spectroheliograph in the hydrogen atmosphere surrounding sun-spots have been explained in two different ways: (1) as true hydrodynamical vortices, resembling great tornadoes, and (2) as electromagnetic phenomena, in which charged particles moving in the solar atmosphere are constrained by the magnetic fields in the spots to follow their lines of force. The principles involved in the electromagnetic theory have been applied to the explanation of the terrestrial aurora by Stormer, who has also developed this theory for the case of sun-spots.(1

Lunar photography with the Hooker Telescope

My justification for contributing to this symposium is certainly not that of special knowledge. I cannot pretend to have made any serious study of the Moon, and therefore my comments on lunar research are entitled to but little weight. But I could not forego the privilege of joining in this tribute of admiration and respect for the work of my friend Professor Brown, whose fundamental investigations on the motion of the Moon have so richly deserved the award of the Bruce Medal

A 100-Inch Mirror for the Solar Observatory

[no abstract

Work for the Amateur Astronomer. II. How to Build a Small Solar Observatory

[No abstract

Lunar photography with the Hooker Telescope

My justification for contributing to this symposium is certainly not that of special knowledge. I cannot pretend to have made any serious study of the Moon, and therefore my comments on lunar research are entitled to but little weight. But I could not forego the privilege of joining in this tribute of admiration and respect for the work of my friend Professor Brown, whose fundamental investigations on the motion of the Moon have so richly deserved the award of the Bruce Medal

Frontiers in Space: Official Publication of the Mount Wilson and Palomar Observatories

The Mount Wilson and Palomar Observatories are situated on two Southern California mountains: the one, Mount Wilson, about 30 miles by road north of Pasadena; and the other, Palomar Mountain, about 130 miles to the southeast. The two observatories, together with the administrative and research centers in Pasadena, are operated jointly by the Carnegie Institution of Washington and the California Institute of Technology in a broad, coordinated program of astronomical research. It is because the two observatories take part in this one unified program that both are included in this one hook. It would he impossible to talk about the past, present, or future of one without reference to the other. Both observatories are largely the result of the lifework of one man: the astronomer George Ellery Hale

The Astrophysical Observatory of the California Institute of Technology

Introduction. - Gift by Rockefeller Trustees to California Institute of Technology of fund to establish and Astrophysical Observatory with 200-inch telescope; co-operation with Carnegie Institution of Washington. The 200-inch telescope. - Selection of equatorial reflector; mirror disks; experiments with fused silica; adoption of new type of Pyrex glass, of low-temperature expansion; successful production of 60-inch, 120-inch, and 200-inch Pyrex disks; development of aluminum mirror surfaces; types of equatorial mountings; yoke type selected. Site. - Choice between Northern and Southern hemispheres; mountain site near California Institute and Mount Wilson Observatory necessary for most effective work; five years' study of meteorological, topographical, and astronomical conditions at several favorable sites; other requirements; final selection to be made soon. Astrophysical laboratory. - Purposes of laboratory; site in Pasadena on California Institute campus; brief description. Instrument shop. - Purpose; site; equipment. Optical shop. - Requirements; site; equipment. Auxiliary instruments. - Attachments of 200-inch telescope; Ross correcting lens; tests with Mount Wilson telescopes; Rayton spectrograph lens; spectra of remote spiral nebulae photographed with 100-inch telescope; extremely short-focus lens designed by British Scientific Instrument Research Association; development of photographic amplifier by Stebbins and Whitford; use with 100-inch telescope; radiometers, etc

A 100-Inch Mirror for the Solar Observatory

[no abstract