PeGASus Newsletter #8 – Nov. 25, 1987

My goodness, how time flies – another newsletter! A lot has been happening recently: progress on the doors, recent observing, an astronomy course, and another meeting. Details follow.

We also have an article on radio astronomy by Gail.


OBSERVATORY NEWS

Since the last newsletter, (but not since the last meeting – as most of you know) we had a break-in. Unfortunately, the generator and the stepladder were stolen. Since then, however, we have purchased (at a good price) another generator, and have a line on a sale-priced stepladder.

The first priority is to replace the doors. We are very fortunate in having personnel in the Trades department at the College who are willing and ready to help. Lloyd Anderson and his students in the welding shop have made us a fine set of doors and, at the time of writing, Bob Martin is planning to install them for us on Saturday. The doors are really sturdy-looking and should repel nearly any assault. Stay tuned…

With the doors installed, we will be able to get on with our other work and projects. The weather is starting to get miserable – it must be time to work on the observatory again!


RECENT EVENTS AT TMO

There hasn’t been much activity out there of late. However, once the doors are on, we can get on with astrophotography and other work with the big telescope. There seems to be quite a bit of interest in photography. The way to do it would be to take chemicals out there – with a working generator, we can have heat in the basement and develop film as it is taken. Instant feedback! Photography would be either “piggy back” with a 35 mm camera or through the large telescope.

Your executive has decided to have our driveway plowed again this year.

On the observing front, we had a nice turnout at the Forests for the World sit on Cranbrook Hill, Sunday night. With 3 telescopes set up, we saw Comet Bradfield (spectacular in the west), Jupiter (bands including possibly the red spot), M27, M57, M31, M32, etc. Why not join us next time?


WHAT’S GOING ON IN THE SKY

  • Jupiter is still prominent, high in the south. With the observatory functional again, photography will be a good bet.
  • Comet Bradfield is very prominent in the west. Photography may be hard since, from TMO, it would be over the city.
  • The Orion Nebula is becoming prominent and will also be a good subject for photography.

SPECIAL NOTE

The long-awaited news is final – if there’s sufficient interest, a one-semester credit astronomy course will be offered at CNC (by yours truly), starting in January. It’ll be two nights a week – Tues and Thurs, from 7:00 to 8:30. (Two nights a week were chosen because many people feel that a 3-hour lecture is too long.) Although the course has to satisfy university requirements, the emphasis will be on making it interesting, lively and non-technical (as far as possible). There will be virtually no pre-requisites and we will minimize the mathematics (although we will still need an equation or two). On clear nights, there will be observing after class (possibly on the roof of the gym). You can take the course for credit, or audit it (for less cost). Why not plan on taking it? More details at the meeting.


RADIO ASTRONOMY By Gail Brawn

As those of us interested in Astronomy will know, there are many facets to the science and hobby of looking at celestial objects. As we know also, there are other methods used to make discoveries and collect observational data. For example, images generated using the Gamma and X-ray ranges of the electromagnetic spectrum reveal detail and phenomena that wouldn’t otherwise be detectable. Of these and the other methods that utilize spectra invisible to the human eye, the practice that I find most interesting is that of radio astronomy.

Beginning in the 1930s with the work of Karl Jansky of Bell Telephone Laboratories, and continuing with the development of radar after World War II, radio astronomy quickly proved itself a valuable tool in our quest for knowledge of our universe. Most methods of gathering electromagnetic radiation have the disadvantage of having their emission either absorbed or deflected by the Earth’s atmosphere. The 1 to 30 centimetre wavelengths of radio find it possible to make their way to the surface of the Earth, and are therefore of much use to us. One of the major advantages of radio astronomy in today’s world is obvious. Radio wave penetrate the atmosphere, weather systems and smog; so it doesn’t require a clear night, or even a night at all, to make use of the telescopes. The information can come or go in a stream interrupted only by the rotation of the Earth away from the source or target. Most radio telescopes consist of a curved dish that collects radio waves andĀ focusesĀ them to an antenna commonly suspended above its centre. The antenna in turn feeds the signal to a receiver in the control room, where it is amplified, recorded on magnetic tap, and the resulting data analysed. When the dish is used for broadcasting, the signal travels from the antenna to the dish, and is reflected on to interstellar space.

Some of our modern technology has resulted in the development of more efficient, more sensitive sending and receiving units. The Arecibo telescope in Puerto Rico measures 1000 feet across, and is situated in a natural bowl in the landscape. (Unfortunately but understandably rendering it almost unsteerable, except for a 50 degree coverage made possible by moving the suspended receiver.) The Very Large Array (VLA) in Socorro, New Mexico is a fully steerable phased array, consisting of 27 separate telescopes arranged in a Y across the plain. The connection between the individual telescopes results in the simulation of a single radio telescope 17 miles [27 km] in diameter. Among its applications, radio astronomy is utilized to communicate with the Viking and other space probes. And many scientists, including Carl Sagan and Frank Drake of Cornell University feel that the discovery of other civilizations somewhere in the Universe will depend almost exclusively on the transmission and detection of radio messages. For such communication, Sagan and Drake advocate the use of the 21 centimetre wavelength emitted by hydrogen gas in space. With the crest of each water-like wave being and “on” signal, end each trough being an “off”, a pulsing code is set up that can carry information. By arranging the message on a grid, each “on” being a black (or filled) square and each “off” being white (or empty), it is possible to send text and pictures on the wave of radiation. And if a receiving civilization was scanning its skies, tuned to this frequency, and could decode the message (with the help of a primer attached to the announcement section of the signal), we would be on our way to the most profound experience of modern human history to date.

With increasingly complex innovations, new progress in the detection and amplification of radio signals enable us to “see” further into our past by observing more distant objects. And a consequence of learning more about our past is learning more about what to expect the future to bring us. And ultimately, isn’t that the most compelling reason for gazing at the heavens?

Thank you, Gail. Hopefully, that will be the start of many more articles from interested members.


MEMBERSHIP

We have at present 18 paid-up members and a re-juvenated society. Our monthly program and observing are really shaping up! Why not come to the next meeting and/or mail in your fees? Paid-up members will continue to receive this newsletter but mailing costs will soon make us trim the mailing list.


NEXT MEETING

Wednesday, Dec 2 at 7:30 PM in room 2-223 (Physics Lab) at CNC. Brian Potts will present a videotape and talk on the Milky Way and nearby galaxies; Paul Ingraham will talk on the featured constellation – Auriga.

Bob Nelson, President