Hints on the Popular Study of Astronomy

Mary Emma Byrd wrote two books and many articles on how to encourage children to become interested in studying the sun, moon, planets and stars. One of the papers was Hints on the 'Popular Study of Astronomy', Sidereal Messenger 6 (1887), 151-156 and we give a version of this paper below.

Hints on the Popular Study of Astronomy by Miss M E Byrd

Everybody looks at the sky, but it is well nigh painful to any student of astronomy to consider how thoughtless and aimless this looking is.

Tonight if everyone would begin to look with some definite object in view, and would do some thinking as well as looking; many would be surprised to find how soon there would be a "new heavens" for them.

The first steps toward this end are very easy, and to any who care to help themselves or others to a little new pleasure in looking skyward, the following hints are addressed. They are given with no claim to originality, but with the hope that someone may find something suggestive. At first two things only are necessary, a notebook and a motto. For the former anything whatever in the shape of a blank book will answer the purpose. For the motto, nothing better can be found than a saying from a letter of the poet Gray, "Half a word fixed on or near the spot is worth a cart load of recollection." The first thing to be done is simply to go out and look at the sky. For once, turn an earnest, attentive gaze heavenward. Frankly face the question: "Do I have-any clear idea of how' the sky looks?"

I verily believe that if the spirits of the air some night should roll away the canopy of our heaven, and spread over us some section of the Milky way, with a different configuration of stars, many intelligent people would never know the difference until they were told.

So first and foremost the question is, "How shall I describe the sky tonight?"

The following are suggested as guiding questions that will help to answer the main one. Are there just as many bright stars in one part of the heavens as in another? Toward the south quarter do I find a number of bright stars that characterise that part of the sky? Can I arrange them in some group so as to fix them in mind, that is in a triangle, parallelogram, five sided figure or any easy configuration? Can I in like manner fix other groups toward the north and east? Is there any connection between the bright stars and the Milky way? How is the Milky way placed in the sky? That is, does it lie toward the north or south horizon? Does it intersect the horizon? If so, where on the horizon are these points of intersection? Is the breadth of the Milky way uniform?

When these and similar queries are answered a description should be written out on the spot, accompanied by sketches of two or three striking groups of stars copied directly from different parts of the sky. Doubtless this first description will seem rather crude to the observer himself; and it will not be amiss to spend some time on a number of evenings in correcting and completing it. The sky can be divided into sections by imaginary lines, and several nights devoted to each. In mapping these sections it is well to employ two or three symbols for stars of different degrees of brightness. Directions are readily checked by connecting any three stars in the copy and noting whether the angle thus formed corresponds with the similar angle between the same stars overhead. In measuring distances in the sky have nothing whatever to do with feet and inches. Let the unit be the distance between two familiar stars, and in imagination lay it off a certain number of times from star to star as the sketch progresses.

The star watcher's experience will be very unique, if a score or two of questions do not suggest themselves to his mind before the sky-picture is finished. Whatever the number all should be carefully entered in the note-book. Some of them very likely lie beyond the ken of the most powerful astronomer, and some are not too difficult for the school girl to answer. But before entering upon the consideration of the easiest, it will be a matter of convenience to have names for some of the bright stars and groups of stars. Astronomers are not interested in the ancient grouping of the stars into constellations, and hardly anyone cares to puzzle out the figures of maidens, horses, beasts and birds, but for those who look at the heavens without telescopes it will be pleasant and convenient to have their hosts marshalled within the old boundaries, and under the old familiar names, Orion, Taurus, Gemini, etc. It will be hard to find any star map, old or new, that will not give all the information desired; and anyone who has followed the preceding hints will have no trouble in locating the bright stars of the different groups within their proper limits.

Even thus humbly equipped. the star gazer is ready to find out the answers to an almost unlimited number of simple questions. Very likely on the first night the question comes to mind, How do the stars move? The first step toward the answer is to break up the general question of motion into several specific questions. Are the stars moving away from or toward one another? Are those in the handle of Ursa Major coming together, or those in Orion's belt moving apart? Or, on the other hand, is the whole host of heaven moving on in marching order, each one always keeping just so far from every other? If careful sketches of the same groups of stars have already been made on different nights, a close comparison of these should enable the observer to decide whether or not the stars have, with regard to one another, a relative motion that can be detected in a short time by the naked eye. In case the question is decided by maps, made for the purpose, attention should be given to relative rather than absolute distances, and care should be taken not to be biased by any theory.

Having ascertained that for naked-eye vision the stars remain always at fixed distances from one another, it will perhaps require some patient watching and mapping to discover the path and direction taken in their orderly march. Orion is not for this purpose a favourable constellation to observe, nor is the answer that the stars rise in the east, pass across the heavens and set in the west, at all satisfactory. The question naturally following has very probably not been entered in the notebook at all. If the time when a particular star comes into line with two fixed terrestrial marks is noted one evening, and on the following evening the time is observed for the same position of the same star, will the interval be more or less than twenty-four hours? Or in other words, is the sidereal day longer or shorter than the mean solar day? As an illustration of a particular method of answering, the following notebook extract is given:

"Northfield, Minn., Feb. 28, 1887. I selected Beta of Ursa Major as my star, and the middle bar of the window sash as the object behind which I waited for the star to disappear. I took my position at the window and noted it carefully. At 7h 15m P.M. I began watching my star, and at 7h 22m P.M. it passed behind the window sash." A similar observation on the following evening enabled the youthful observer to secure quite an accurate answer to the question proposed.

The moon is the most accommodating of heavenly bodies in furnishing a large number of simple questions some of which can be answered in a single clear night. Does the moon move among the stars? In what direction? What is the hourly rate of motion in terms of its own diameter? Two sketches of the moon and a familiar star near it furnish the necessary data. It will be well to have an interval of three or four hours between the sketches, and to take the comparison star near enough to measure its distance conveniently in units of the moon's diameter, i.e., in half degrees. The following are some of the queries that require longer consideration. In any given month is the moon's path in the sky constant? Helping questions are such as these: Does the moon uniformly rise and set at the same points on the horizon? Midway between these points is the zenith distant constant? If there are variations, is the moon moving toward or from the zenith? Are the points of rising and setting moving north or south? It is not at all difficult to fix the point where the moon rises. Choose some convenient place for watching just as the moon begins to appear above the horizon, select two fixed objects in line from the point of view, and so taken that the line prolonged will meet the horizon not very far from the moon, then calculate how many half degrees, i.e., full moons, can lie between the imaginary point of intersection and the moon's centre.

In the notebook entry, the fixed objects should be sketched or described so as to be easily identified on following nights. After this there comes the still larger question of comparing the paths of the moon in different months. If one can only have patience to collect data throughout the year, some interesting results will be secured. In order to trace the real path of the moon among the stars for any month it is best to make a rough map of the constellations of the zodiac above the horizon, and locate upon it the position of the moon observed as often as possible on different nights and at different hours of the same night. An easy way to make the map is to lay tissue paper upon the printed map and then mark down such stars as are desired. If such maps are made for different months, the question can be answered whether the moon's path among the stars varies from month to month.

Many of the questions about the moon will apply to the sun and some will not be found too difficult. There is also a whole host of questions about the relative paths of the sun and moon which will naturally suggest themselves.

One can hardly look up at the bright planets without wishing to find out something about them by personal observation.

They are surely moving among the stars.

Are different planets moving with equal rapidity? Is the same planet always moving in the same direction? How is the direction in which a particular planet moves at a given time ascertained? For these and like queries, careful sketching is the key. As a more definite hint for the last, a portion of an entry from a school-boy's note-book is added. Saturn has been carefully located on two sketches including the principal stars in Gemini, the interval being nearly a month. "I compared these two maps, and found on the first map that Saturn was situated about midway between two stars in a small triangle [stars of triangle identified on celestial globe], which is about one half further from Pollux than Castor is. In the second map I find that Saturn has moved away from this first position toward the west. In this map it is seen a trifle above and away from this triangle and away from Pollux. So I find that Saturn is moving westward slowly and the motion is retrograde."

Looking at the sky according to some such method as has been suggested will not be found burdensome or difficult, and it cannot but give pleasure to replace the general vague notion of the spangled blue overhead with some simple but definite knowledge about the sky.

Last Updated June 2023