Secrets of the Deep Sky
These ultra-performance receiving preamplifiers are suitable to the most demanding needs where low noise figure is important. Uses include all types of weak signal work such as EME, Tropo & ionosphere Scatter, Satelfite Communications, Radio Astronomy, Meteor Scatter, etc.
Radio amateurs have been successfully bouncing VHF, UHF and microwave signals off the surface of the moon, and receiving their echoes, for nearly forty years. EME (Earth-moon-Earth) activities have enhanced the teaching of disciplines as diverse as electronics, astronomy, and physics, with several generations of students having now used measured echoes to determine the distance to, and orbital parameters of, the moon. Penn College students have recently had an opportunity to apply these measurements on a truly grand scale, using EME signals to measure the mass of the Earth. Their results differ from the currently accepted figure by about one percent.
Any astronomy textbook will reveal multiple measurement errors for each of the intermediate values which we used to estimate the mass of the Earth. For example, the actual period of the lunar orbit is about two percent less than we estimated through our rather crude calendar technique. The lunar radius is in fact nearly four percent greater than we estimated through visual observation and simple trigonometry. And the radius of the moon's orbit turns out to be about a percent and a half less than we calculated from our echo measurements.
What can you do with an A-D converter An A-D converter lets you get information from lhe +ioutside world into your computer It seems that everyone has his own unique need for data acquisition, A-D converters are used in astronomy, seismology, plant growth research, and a host of other applications. An A-D convener can monitor battery voltages, RF power levels, fluid levels and pressures- practically everything can be monitored with the proper
Christian Doppler was born into a family that had built a successful stonemasonry business for 125 years, but his health was always too bad for that arduous occupation. Aftfir studying mathematics and astronomy at two institutes in Vienna, he sought a career as a professor. Despite being quite ambitious and having already published four papers in mathematics, he was turned down for several positions. There was no way to measure tiny shifts in apparent color from stars in those days, so Doppler couldn't directly prove his hypothesis by experiment. Most astronomers pooh-poohed it. Six years later, Doppler set astronomy aside and took on a new scientific interest, studying the Earth's magnetic field as a teacher at the Academy of Mines in Slovakia, His publication topics included changes in Earth's magnetic declination, another subject of interest to hams who are mobile T-hunters.
INCREASING USE OF THE 2-GHz bands for long-haul communications and for satellite tracking and telemetry, coupled with the growth of navigational systems, radio astronomy and meteorology in the 1 to 2 GHz band, has intensified the need for precision test instrumentation for this range of frequencies. At the same time there is increasing use of phase modulation (M) in communications, telemetry, and navigation systems, so phase-modulated signal generators are needed for testing these systems.
The careful astronomical observations of Tycho Brahe and the brilliant analysis of his data by Johannes Kepler illustrate very dramatically the contribution of accurate measurement to scientific progress. Plato, and the Greek philosophers who followed him, believed that the heavenly bodies, being perfect, were composed of the quintessence (literally the fifth essence of matter as distinct from earth, fire, air, and water) and that their motions must be eternal and perfect. Certainly the stars moved in circles, and it was believed that the motions of the planets could be described by an appropriate combination of uniform circular motions. For two thousand years the resolution of planetary motions into circular components was considered the most important problem in astronomy. The heliocentric theory of Aristarchus of Samos (250 B.C.), the geocentric theory of Ptolemy (A.D. 150), and even the heliocentric theory of Copernicus (A.D. 1543), all adhered to the concept of circular motions....
When students at all grade levels arc asked today what pan of the curriculum offered hy schools interests them most, astronomy and space science arc high on their lists. As director of a public school planetarium for the past 20 years, I have seen thousands of students thrill to the sight of the night sky and to the spacecraft, such as Voyager and Viking, that have probed through the blackness of space to the planets of our Solar System, Students often ask me how these spacecraft yet where they are going, and how the information they gather is sent back to waiting scientists on Earth. The also w ant to know how communication satellites work, and how some of those birds can just hant there in the sky.
Such noise is basically due to the statistical unpredictability of energy-level changes within the individual atoms which go to make up the universe, and because of this is always present. In amateur practice, it is generally characterized by its apparent origin. Thus we have, for example, antenna noise which is present with the signal when it arrives from the antenna. This is, in turn, composed of galactic noise which arrives from outer space, atmospheric noise which originates within our own atmosphere and ionosphere, and thermal noise which originates within the conductors of the antenna and feedline (as well as within the components of the amplifier's first rf amplifier stage). Noise of this sort is always proportional to temperature the higher the temperature, the greater the noise voltage. In fact, in radio astronomy noise levels are measured in degrees Kelvin which are a measure of the temperature of the apparent noise source.
Amateur Radio Astronomy if you'd like to get into amateur radio astronomy, an international organization exists to help you. For information on how to get started wnte S A.R.A Membership Ser While it's unlikely that amateur radio astronomers can compete with the huge antennas used by professionals, amateurs can pursue various rewarding projects indirect monitoring of solar flares, meteor monrtoring, imaging of strong radio sources, pulsar detection, and Jupiter studies. Most of these projects require simple, though sensitive, equipment and relatively small antennas You do not have to be an electronic wizard to obtain thnfling results Radio telescopes consfst of the same type of equipment in amateur radio stations, only they are arranged differ enlly. (From Watts New )
Fred Moore, W3WZU, broadcast engineer, 4357 Buck field Terrace, Trevose, Pa. 19047. Novice transmitters and receivers, IIF and VHF antennas, VHF converters, receivers, AM, SSB, semiconductors, mobile, test equipment, general, product data, pulse techniques, radio astronomy* bio-medical electronics.
According to the Encyclopedia Britannica, (ASTRONOMY), '54, Kepler's 3rd law, being a necessary consequence of the law of gravitation, must prevail in every system under its sway. Also, The Rudolphine Tables computer by him (Kepier) from elliptic elements, retained authority for a century, and have in principle never been superseded. Furthermore, the importance of Kepler's generalizations was not fully appreciated until Sir
Greg Bourque has been a principal developer of the Pascal 64000 compiler since he joined HP in 1977 A native ot Amityvllle. New York, he received a BS degree in astronomy from California Institute of Technology in 1968 and an MA degree in astronomy from the University of California at Los Angeles in 1970. Before joining HP he worked as a nuclear astrophysicist and as a scientific programmer and computer consultant He's a member of AAAS and the HP Pascal standard task force, and has lectured in FORTRAN at Colorado State University. Greg is married, has two children, and lives in Colorado Springs. Colorado He fiils his spare time with raising his family, gardening, landscaping, astronomy, and working on his PhD thesis, which he expects to complete nexl year
M ICROWAVE signal sources of high frequency-stability and spectral purity are increasingly important to many fit-ids. These include doppler systems, nuclear spectroscopy measurements, spectrum analyzers, as well as telemetry, radio astronomy, and other communications-type work. All of these applications are characterized reduced typically by about 10 times. The synchronized klystron is thus useful as a local oscillator in the most sophisticated receivers such as dop-pler-tracking receivers, telemetry or radio-astronomy receivers, or as a pump in receivers employing masers as low-noise input amplifiers. The arrangement also permits greater latitude in the selection of a klystron, since more emphasis can be placed on achieving other characteristics such as power output, environmental tolerance, tuning characteristics and reliability.
Before developing further the theory of vacuum tubes, a suitable system of notations or letter symbols must be adopted in order to denote easily the many different quantities involved. Although several schemes of notation have been suggested, no one system as yet has come into general use. A satisfactory system of symbols is urgently needed because of the exceptionally large number of different components and aspects of the same quantity necessary to be distinguished in this field. For example, the potential between two points may consist of a steady value on which is superimposed a periodically changing value. We have then to deal with the steady value, average value, peak value, and maximum value of a harmonic component, total instantaneous value, instantaneous value measured from the average value and also from the steady value, etc. The symbols should be such as to suggest, as far as possible, the quantities represented and to burden the memory of the reader as little as possible....
Over the course of the iast seven years packet radio has developed into amateur radio's fastest growing mode. The computer hackers love itt some operators find it useful for obtaining the latest information on a variety of subjects from ham radio to amateur astronomy, and other operators find that packet is no1 their cup of tea One thing stands incontestable, however Packet has become prevalent in virtually all aspects of our hobby. Visit any reasonably large city, tune around 144.91 145.09 MHz, and the sound of various packet networks will greet you. Tune the HF bands near the domain of what used 10 be our primary digital mode (RTTY), and agam the sound of 300 baud packet bursts will be heard, irtually all o- the new amateur satellites use packet as the communications medium Most importantly, packet has given the amateur community visibility and recognition by advancing the state of the art in digital communications.
Daring the mid-1970's when the Voyager's were launched into space, the media was excited about information the craft would carry of planet Earth and its inhabitants. Should the probe be discovered by another deep-space civilization or land on an inhabited planet, these beings could learn about our solar system and the life it contains. Since that time, radio astronomy and the search for extraterrestrial life became a serious matter for many professional and amateur scientists.
Twenty-seven dishes in a twenty-one-mile pattern makes for some serious DXingat the National Radio Astronomy Observatory. The Very Large Array in New Mexico is the world's most advanced radio astronomy observatory, ihts observatory, whjrh looks (ike a huge Y when seen from the air, is located near Sot orro on the Plains of The VLA (Very Large Array) radio observatory was constructed by the National Radio Astronomy Observatory (NRAO , NRAO, which is funded by the National Science Foundation, is also Photos the National Radio Astronomy Observatory, operated by Associated Universities, Inc., under contract with the National Science Foundation The electromagnetic spectrum ranges from the extremely short gamma rays to long radio waves All parts of this spectrum are of interest to astronomers. Only visible light, radio waves, and portions of the ultraviolet and infrared wavelengths can be observed from the ground as the atmosphere shields lis from the rest of the electromagnetic spectrum....
The active radio observatory at Green Bank, West Virginia, is also a center for preserving some of the major early developments in radio astronomy. Green Bank has become a center for the history of radio astronomy as well as an active radio observatory. A replica of the first antenna that was used to detect radio emissions from space has been constructed near the administr t ion building. The original antenna was built by Karl Jansky, a radio amateur who worked as a scientist at Bell Laboratories in Hoimdel. New Jersey, With his antenna system, Karl Jansk was studying radio noise. The antenna was constructed fora wavelength of 14,6 meters, which is near our 15-meter radio band. He discovered that the strongest noise sources seemed to follow the movement of the sky as the Earth rotated, In 19.10 Karl Jansky determined that the band ol radio noise that he detected seemed to coincide with the Milky Way and that it was strongest near the constellation Sagittarius, the center of the Milky...
These ultra-peHormance recer. ng pre-amps re suitable to the most demandtnq needs whure low noise figure is important Uses include all types of weak signal work such as EME Trope lono and Meteor Scatter Satellite Communications, Padao Astronomy weak, etc Absolutely the highest quality construction and components
These ultra-performance ANGLEtlNEAR receiving preamplifiers ere suitable to the most demanding needs where low noise figure is important. Amateur Radio. Commercial. NASA & Military users have lauded their superior performance. Uses include all types of weak signal work such as EWE. Traps 5 Ionospheric Scalier. Satellite Communications. Radio Astronomy, Meteor Scalier, etc.
A satellite tracking program from RPV Astronomy. RPV Astronomy David H. Ransom, Jr. 7130 Avenida Aitisinia Rancho Palos Verdcs CA BBS (310) 54I -7299 2,400-14,400 baud) Keplerian elements are factors vised to compute the location of satellites. This data is available from the ARRL, AMSATt the RPV Astronomy BBS (above) and many other sources,
Fred Moore, W3WZU, broadcast engineer, 4357 Buckfield Terrace, Trevose, Pa. 19047. Novice transmitters and receivers, HF ant VHF antennas, VHF converters, receivers, AM, SSB, semiconductors, mobile, test equipment, general, product data, pulse techniques, radio astronomy, bio-medical electronics.
By now, control had been passed to VK2AS in Sydney, and Brian, in Ron Curry's group, asked the last question What do you expect to find concerning Ihe Super nova of 1987 'h We are not sure of Ron's answer because our recorder ran out of tape at this point Even so, the astronomy lesson and the SAREX contact were a smashing success for amateur radiof
People having an interest in time and frequency standard signals (astronomy, piano tin ling, watch adjustment, event timing, etc.) will find tlie receiver ideal. Channel one brings in WWV on 2.5 MHz, channel two tunes CHU on 3335 kHz, channel four tunes WWV on 5 MHz, and channel three can be retuned to bring in CHU on 7335 kHz. At least one of these should be available at all times of the day or night.
In 1848, a method was introduced for the daily measurement of sunspot numbers. That method, which is still used today, was devised by the Swiss astronomer, Johann Rudolph Wolf. The observer counts the total number of spots visible on the face of the sun and the number of groups into which they are clustered, because neither quantity alone provides a satisfactory measure of sunspot activity. The observer's sunspot number for that day is computed by multiplying the number of groups he sees by ten, and then adding to this value the number of individual spots. As can readily be understood, results from one observer to another can vary greatly. Measurement depends on the capability of the equipment in use, on the stability of the earth's atmosphere at the time of observation, and on the experience of the observer. A number of observatories around the world cooperate in measuring solar activity. A weighted average of the data is used to determine the International Sunspot Number or ISN for...
The predicted maximum deflection is 1.75 seconds of arc. To increase the accuracy of the experiment, interferometric techniques will be used two widely separated passive antennas will receive the signals and the phase differences between the two received signals will be measured to determine the direction from which the energy appears to come. The initial attempt to perform this experiment is planned for late 1968. Working with Lincoln Laboratory's Haystack site will be the National Radio Astronomy Ob
Last month's Homing In took you on a journey that started with Christian Doppler's birth almost exactly two ccnturies ago While trying to understand color changes in double stars, this astronomer physicist ivas the first to document the apparent frequency shift of waves when source and observer are in relative motion.
All telemetry relates to the radio astronomy experiment. There is no housekeeping data. The information for decoding and processing the telemetry will be published soon. Then you will have an opportunity to analyze and correlate the downlink data and, perhaps, discover something new. SARA, albeit a simple satellite, may provide amateurs with a tool to make new discoveries in radio astronomy. AMSAT element bulletins contain sets for SARA.
Fred Moore, W3WZUt broadcast engineer, 4357 Buckfleld Terrace, Trevose, Pa. 19047. Novice transmitters and receivers, HF and VHF antennas, VHF converters, receivers, AM, SSB, semiconductors, mobile test equipment, general, product data, pulse techniques, radio astronomy, bio-medica eiectronics.
Fred Moore, W3WZU, broadcast engineer, 4357 Buckfield Terrace, Trevose, Pa. 19047. Novice transmitters and receivers, HF and VHF antennas, VHF converters, receivers, AM, SSB, semiconductors, mobile test equipment, general, product data, pulse techniques, radio astronomy, bio-medical eiec-tronics.
Rd love to talk about cold fusion, sky diving, scuba diving, cooking, and any of a hundred or so things I'm interested in. One time on a ski lift in Aspen I met one of the Jeading astronomers and we had a momentary taJk about the bubbly nature of the universe, which he d recently helped discover. Another time I went up the lift with Mike Markkuia, the chap almost singularly responsible for Apple's growth in the early days. Mike is not a ham. Nor was the astronomer
Through this ebook, you are going to learn what you will need to know all about the telescopes that can provide a fun and rewarding hobby for you and your family!