While variable-star observing is a specialized branch of observational astronomy, the basic procedures of patience and care that apply to all observing also work with variables.

Plan your program in advance, but be flexible, since the sky often offers surprises. Choose your variable carefully. Is the star likely to be visible through your telescope, or is it obviously too faint? At the other extreme, is your star so bright that observing it is a waste of your precious telescope time?

Telescope

Telescope size

This is more of a consideration than most observers realize. In a sense, each variable star has its own best combination of telescope and eyepiece. The general rule is to use only enough power and magnification to see the variable clearly but not have it so bright that it is hard to estimate. Ideally, the variable should be about two magnitudes brighter than the faintest star you can see with your telescope. If it is much fainter than that, you will have a problem seeing the star, and if the variable is several magnitudes brighter, so many photons will enter your eye that its sensitivity to subtle magnitude variations will be affected.

At minimum, a star might be fair game for most telescopes smaller than 30 cm (12 inches), but as the star brightens you could use a smaller telescope. (When discussing a telescope size, I refer to the size of the mirror or objective lens.)

What else does the sky have that varies? Besides stars, there are other objects worth noting. Some are easily visible, and others are beyond the reach of all but the most powerful telescopes and detectors. They range in distance from a few million kilometers to billions of light years.

Variable nebulae

In the constellation of Monoceros is a variable star called R. It varies irregularly by about half a magnitude around 11. However, the star is usually very hard to see. The reason is that it is embedded in a nebula which also varies in brightness! This object is known as Hubble's variable nebula, NGC 2261, after the Mount Wilson astronomer who, in 1916, discovered that it varies in brightness, size, and even shape. The variation does not seem to follow the brightness changes in R Mon, and they do not occur with any regularity.

R Monocerotis and its nebula probably represent a planetary system in an early stage of formation. At least two other variable nebulae are known, NGC 1555 in Taurus, and a tiny wisp in Corona Austrina, NGC 6729, the home of R Coronae Austrinae (see Section 29.8).

Active galaxies

Innocently displaying some irregular brightness changes are a number of objects that have recently been identified as the cores of galaxies. The Seyfert galaxies are spiral galaxies with starlike nuclei that are very bright and slightly variable.

Introduction

In 1944, three years before India became independent of British rule, Jawaharlal Nehru wrote in his now famous book Discovery of India:

He then went on to express the hope that “Only when we are politically and economically free will the mind function normally and critically.” India became independent in 1947 with Nehru as the first Prime Minister, a post that he held for nearly 17 years. Ever an advocate of science and technology as the means of progress, he encouraged establishment of a good scientific infrastructure and also looked after achieving industrial growth. However, what has been the net outcome so far as human resources are concerned? Now we are well into the sixth decade after independence: where do we stand vis-à-vis Nehru's expectations of rational thinking?

This season is variable time, with a cast of variables probably better than at any other time during the year. We still have the fine variables of the Milky Way, while toward the east, a different group of variables is gaining prominence.

This is also the time to get your fellow astronomy-club members excited about the challenging field of variables. Fall is the time for renewal in many northern-hemisphere astronomy clubs, where after the summer break, monthly programs and dark-of-the-Moon star parties are taking place once again. If you are fanatical about variables, you may be aware that this field of observing is not the most popular among the amateurs who attend astronomy club meetings. Observations of the changing light output of these distant suns are perceived to lack the luster of the Messier hunt or the glossy galaxy photo, and even the thrill of the meteor watch. Now is the time to insist that variables are fun.

Now we can observe Algol in all its glory, and use it as a motivation to start observing other eclipsing binaries. Two other easily found, easily observed stars are Delta Cephei, and its neighbor Mu Cephei, a huge red-giant sun with totally irregular and unpredictable variations.

Another exciting star is RU Pegasi, a dwarf nova. You never know exactly when the next outburst will take place! While RU Peg may be one of the most exciting stars of fall, it surely is not the most famous.

Introduction

The curriculum and the teaching of astronomy in any school are driven by the syllabus and the individual school's developed and implemented curriculum. Other factors that may affect the delivery of the intended curriculum will include the competence and interests of individual teachers and the use of textbooks and other resources, to support this curriculum. The successful teaching of astronomy in primary and secondary schools is dependent on the teachers' own understanding of concepts and abilities to challenge students' prior conceptions, therefore the courses undertaken by pre-service teachers must be in the context of teaching astronomy, and teachers' own studies must challenge and develop their own understanding of concepts in astronomy.

To understand fully the possible derivation of alternative conceptions or difficulties in understanding key concepts in astronomy, it is essential to trace the stages of teaching and learning in astronomy through the curriculum. It may be that students have not been provided with the opportunities to challenge and/or restructure their prior knowledge or intuitive beliefs through appropriate teaching strategies.

The prefix “pseudo” is derived from a Greek word meaning “false.” Pseudoscience refers to theories, assumptions, and methods that are mistakenly thought to be scientific. Obviously the distinction between science and pseudoscience is not clear-cut. Pseudoscience overlaps with scientific “misconceptions” - beliefs that are held by students and the general public that differ from scientific fact. Both of these concepts are subtle ones, since all scientific theories can be regarded as tentative to some degree.

At the 1996 IAU conference on astronomy education in London, UK, Neil Comins classified astronomical misconceptions into about 20 types, and he has described these in detail in his book Heavenly Errors (Columbia University Press, 2001). Some misconceptions are cognitive in nature; they are dealt with in our Part II. Others are products of religious belief or superstition (often transmitted through the “authority” of family or friends), or popular culture, or errors or excesses of the media. In relation to astronomy, notable pseudosciences include astrology, space aliens, and creationism; the works of Velikovsky also fall under the pseudoscience rubric. The majority of students will be affected in some way by these beliefs.

How to deal with them? The theory of constructivism is one of the most influential sciencelearning theories in schools today. It states that, by reflecting on their own knowledge and experiences, students build their own new knowledge about the universe around them. Teachers must therefore be aware of students' pseudoscientific beliefs, as well as their other misconceptions, if they are to correct them through their teaching. Many of them are deeply rooted. They cannot easily be changed by lectures and textbooks. They must be confronted through minds-on teaching.

Delta Cephei

To get an idea of what variable-star observing is all about, here are two active, easily found stars that we will observe informally. The first is Delta Cephei, an ideal star to begin with for several reasons. It is part of a bright and compact star group, is usually around magnitude 4, and is an active star, always offering something interesting to watch.

Delta Cephei's variation was discovered by John Goodricke in 1784 (see Chapter 32), and it is the star for which all the Cepheid variables are named. The variation in this giant star is small but extremely regular with a period of several days. It is also typical that this star enjoys a leisurely decline to minimum that is followed by a rapid rise to maximum.

At maximum, Delta Cephei is easily visible at magnitude 3.5, and at minimum it shines at 4.4. If you observe every night or two you will soon see how it falls, then rises, week after week.

Notice the two stars Zeta and Epsilon in Fig. 6.1 and in the sky. Which is brighter? Let us give Zeta Cephei an arbitrary value of “1” and Epsilon a value of “5”. Each night estimate the brightness of Delta Cephei as follows:

1. – as bright as Zeta

2. – slightly fainter than Zeta

3. – halfway between Zeta and Epsilon

4. – slightly brighter than Epsilon

5. – as faint as Epsilon

Even though we are not using actual magnitude values here, we still estimate to better than 0.2 magnitude.

Introduction

The Astronomy Education Review (AER), a new electronic journal, was established to serve the growing community of researchers and educators who are active contributors to astronomy and space science education.

For decades, it has been a cause for concern that too few US undergraduates are being trained in science, engineering, and mathematics (NCEE, 1983). In addition, our increasingly technological society requires citizenry that is at least somewhat literate in science. As a consequence, National Aeronautics and Space Administration (NASA) and National Science Foundation (NSF) have committed very significant resources toward improving both access to, and the quality of, science education at all levels. Proposals to the NSF are now judged not only on the intellectual merit of the proposed research but also on its broader impacts, including how well the work will advance “discovery and understanding while promoting teaching, training and learning” (NSF, 2004).

The afternoon summer storm has just passed and the sky is clearing rapidly. It's a weekend evening and you decide to set up the telescope. By the time the Sun has set, your telescope is assembled and you are ready for a night with the stars. What do you do first? While the telescope is adjusting to nighttime temperatures, check out the sky. Is it just as you left it last time? A good way to begin any night of observing is to review the familiar constellations and asterisms. Slowly and methodically check each star down to 2nd or 3rd magnitude. In all likelihood, all is well, but you never know. An erupting star, a nova, might be out there waiting to be noticed as a “star out of place.” A nova is not, as its Latin name implies, a new star. It is really an old star system that is exploding. In the case of an ordinary nova it is a binary system that goes into outburst as it blows off some of its atmosphere, or as a supernova, it spectacularly blows a large fraction of its mass over space.

A nova in Cygnus

On a Saturday evening in late August 1975, when I was returning with friends from an early dinner, I looked up, quite by habit, and saw what I assumed to be a slow-moving satellite just north of Deneb.

Stars are people, too. Each star, like each person, is unique. For whatever efforts we make to classify either people or stars, we always run into exceptions, and when we create a new category for the exceptions to the old category, that usually turns out to have exceptions as well. Although it is an exaggeration to say that every variable star in the sky is in a class by itself, it is useful to think of variables as individuals capable of surprises.

There is a different aspect, however, of the philosophy of classification. Just as we can find strength and beauty by looking at the diversity of language, behavior, and culture in people, a look at the kinds of variation in stars will help to show just how extraordinary this field of study really is.

Some classifications are obvious. You would never want to confuse a stately, mature, slowly varying red giant like Mira with a little dwarf star that erupts every two months. An Orion variable, changing brightness for no apparent rhyme or reason, would not be confused with a slightly unpredictable semiregular. The eclipsing binaries, revolving together in clockwork fashion, are not the same as the intricate “breathing” of the Cepheids. Astronomers recognize these broad divisions that help us both to understand the different patterns of variation and to plan our observing programs for them.

Standardized testing and the scientific funnel

A national trend in the United States since 2002 has been an increase in required standardized testing, often as part of the No Child Left Behind Act (NCLBA). The unforeseen consequences of NCLBA seem to be an increasing rate of failures and the abandoning of topics of secondary importance - like astronomy - next to reading, writing, and arithmetic.

In New York State, for example, the percentages of students passing the 2003 mathematics exam required for high-school graduation was so far below 50 per cent that the test had to be withdrawn, though similar problems with the physics exam did not lead to a similar temporary solution (Winerip, 2003).

Editors' Note: This paper was solicited by the editors in March 2004.

Nearly 250 outreach professionals in the astronomical community gathered in Washington, DC, on October 1–3, 2003, to attend the “Conference on Communicating Astronomy to the Public.” This three-day conference attracted public information officers, astronomers, educators, and members of the entertainment and news media to explore the gaps in outreach, the current and emerging demands of the public, the needs of the astronomical community, and to work on methods to answer these needs. “Education and Public Outreach,” now often abbreviated as “E/PO,” was the overall subject.

The conference was organized by the National Radio Astronomy Observatory (NRAO), for which I am a public information officer, and hosted by the US National Research Council. The morning sessions of this conference were based on a series of panel discussions, addressing such topics as astronomy in entertainment, image repositories, best practices, and underdeveloped audiences.