Russian Proposes GLOBAL TV
THE RATHER LIMITED conception of radio transmission we had back in 1925, when we wondered whether radio waves could be propagated through space (see opposite page), has progressed to a stage where today we are near the point of transmitting television through space. With the launching of the first Sputnik last October, the dream of global TV received a tremendous shot in the arm and it has gathered momentum with each additional satellite thrown into the skyâ€”both Russian and American. The magazine which first published data on Sputnik I, the Soviet periodical Radio, has outlined a plan which would allow nearly every TV set anywhere on earth to pick up a program transmitted from any other point. Television today, of course, is pretty much limited by line of sight, except in those areas which have coaxial cables, and a few spots which are equipped with over-the-horizon scatter facilities. The system proposed by engineer V. Petrov would make use of satellites which would pick up signals from stations on earth and bounce them to other satellites for more distant relay.
If a satellite is launched from the equator so that it follows an eastward track at the proper speed and height, it will remain over one spot on the equator. In other words, if it went into orbit over Belem in Brazil, or Stanleyville in the Belgian Congo, or Singapore in Malaya, it would remain fixed in the sky over that spot. This is becauseâ€”if the velocity and height are correctâ€”the speed of the satellite will exactly match the eastward rotation of the earth. It will be making an orbit of the earth once in 24 hours (compared to the 90 to 106 minutes or so for the present satellites. Since the earth rotates on its axis once in 24 hours, there will be no relative motion between the two spheres.
I’m not sure if they still do this at the new Hayden, or if they do elsewhere, but it’s really cool. Basically using a set of mirrors they project an image of the sun onto the roof of the planetarium, so you get 26 foot wide image that’s safe to stare at.
Bringing the Sun Indoors
AT the Hayden Planetarium in New York a huge 26-foot image of the sun is being projected on the interior of the dome every day that the sun shines. This is accomplished by means of a first system of moving and fixed flat mirrors for bringing the sun’s image indoors and a second system of mirrors and lenses for enlarging and projecting it.
The actual sun is shown at the top of the drawing. Its rays are caught by an eight-inch flat mirror mounted on an axis parallel with the earth’s axis. A clock-like mechanism slowly turns this mirror as the earth’s turning “moves” the sun. This image, after passing through an opening in the building, is kept constantly spotted on a second flat mirror which is permanently fixed in position. It in turn passes the image downward to the third element of the Jong optical train, a flat mirror fixed at a 45-degree angle which turns it horizontally. The sun’s image is now where it can be used but as yet it is neither magnified nor projected.
Magnification is done in an ordinary eight-inch reflecting telescope, just as it would be if that telescope were directed at the sun out of doors; and since it is possible with any telescope to view the image not alone by looking into the eyepiece but also by projecting it on a screen at some distance from the eyepiece, the same is done at the planetarium. Here the distance is long, hence the image is very largeâ€”larger, in fact, than any solar image previously projected by similar methods. All this apparatusâ€”the coelostat, fixed flats, and telescopeâ€”is entirely separate from the regular planetarium apparatus and could be similarly used with any ordinary house or building.
The Amateur Telescope Maker’s Page
A Grinding Rig
WALKING around a barrel is undoubtedly a tedious procedure, but on the other hand it is the simplest method of grinding and polishing a telescope mirror. However, a number of our disciples have evidently gotten just a bit tired of this ambulatory procedure and have written to inqure whether there exists a more satisfactory and sedentary method of grinding said telescope mirrors. There is. As a matter of fact a number of such grinding rigs are described in Amateur Telescoping Making edited by Albert Ingalls.
This reminds me of the ill-fated Rotary Rocket company.
Daring Rocketmen to Invade the Stratosphere
The rocket-shooters are going to pitch in again this coming summer. Undaunted by reverses and tragedies during the past year’s experiments, the rocketeers are tackling their work with renewed vigor and ambition, plus improved apparatus and chemicals.
Ernst Loebell, famous German engineer and rocket designer, promises to bring the rocket engines to their greatest point of achievement next summer. He is now in this country and is an active worker in the Cleveland Rocket Society.
Loebell has been carrying on bis preliminary experiments on the big Hanna estate in a suburb of Cleveland. In their operations the Cleveland group has been making use of the lessons taught by the experiments of Loebell’s countryman, the late Reinhold Tilling, a noted radio engineer and rocket builder.
Prior to his death. Tilling had been experimenting with rockets and rocket planes for months. The success of a rocket which reached a height of (6,000 feet in 1931 spurred him on to the construction of a rocket with glider wings which unfolded when the fuel was exhausted and brought the projectile gently to earth. This feat was hailed as one of the first practical steps toward the development of mail and passenger carrying rockets.
The Tilling rockets were set in motion by telignition from a distance of 100 yards. They attained a speed of 700 miles an hour and landed five miles from the starting point, in accordance with calculations. Herr Tilling was working on a system designed to manipulate his rockets by radio control when he and a female assistant were killed in the explosion of a rocket which they were charging.
Skyful of Moons: To aid navigation by ships and planes, a Chrysler Corporation missile engineer, L. Lawrence Jr., has worked out a plan to launch three satellites – Astro 1, 2, 3 – to circle the earth at 600-mile altitude in 105 minutes, in polar orbits crossing the equator at spaced intervals around the world. The satellites would constantly emit radio signals, enabling a navigator to get his bearings from the nearest one, with the help of an almanac giving each satellite’s position at any time. To power a satellite’s radio, an atomic battery would convert heat from radiactive strontium into electricity, by means of a thermopile.