Learning the Stars

Beginner's guide to the Heavens

[For those who just want to jump right into the constellations: Binocular Menu]

This feature concentrates on introducing the constellations to those who have just discovered astronomy as a hobby.

You can find here any constellation which interests you, although the principal idea is to study those which are currently visible.

You don't need an expensive telescope to enjoy the heavens. In fact we will use two means of stargazing -- the naked eye and binoculars. The examples I give in the texts use the field of vision of 10x50 binoculars. Although many recommend this size for astronomy other sizes may do as well -- even 7x35 field binoculars will give you plenty of enjoyment, even though there are binaries you won't be able to split or deep sky objects which won't be very appealing.

If you are looking to purchase binoculars, besides 10x50 I would recommend 7x50. While larger powered binoculars, greater than 10x, might bring slightly more enjoyment, they are rather more expensive and their size means a stabilizing tripod is necessary to eliminate the jiggling. This reduces the flexibility of the binoculars. In fact, if you plan on a long session even 10x50s can use a tripod.

Before you buy, talk to shop owners, read journals such as Astronomy and Sky & Telescope, and ask questions on news groups such as "sci.astro.amateur" and "alt.astronomy". While I might wish that I could personally answer such questions as "is Bausch and Lomb better than Nikon?" or "how much should I pay for a really good pair?", I'm afraid that I really can't take on this responsibility.

I make one assumption when describing the stars of a constellation. That assumption is that the constellation in question is straddling the meridian, that is, is due south of the viewer. In practice this is not always the case, but it is a convenient convention.
    An exception to this rule is when I discuss circumpolar constellations. Circumpolar constellations are those which never sink below the horizon, such as Ursa Major and Cassiopeia if you live in Seattle or Winnipeg, or Toucan and Pavo if you live in Sydney or Christchurch. While I live in the northern hemisphere, the web site does cover all constellations, and is suitable for viewers from either hemisphere.


    Circumpolar constellations change their aspect dramatically throughout the night. In the early evening one might have to go 'east' or right of a major star to find a particular object; as night progresses the constellation has turned such that the direction may appear to be 'up' or apparently north but it's still actually east! (It becomes really confusing when the constellation has made a half-circle and is now below the Pole Star. Now in order to move 'east' of your star you have to move toward the western horizon!)

    Before you can understand the north and south of a particular star you need to know where the Pole Star is (North or South). In the Northern Hemisphere, this means you must first locate the familiar "Big Dipper" (or Plough in the UK) that makes up part of Ursa Major. Study Ursa Major on this web site or in my Pocket Guide if you've purchased a copy. Now draw a line from beta Ursae Majoris through alpha, and right on past until you encounter the tip of the handle of the "little dipper", much fainter but a distinct dipper none the less. This is the Pole Star and is the brightest star of this fairly dim constellation. Once you've found it in the skies, make a mental note of where it is. It won't drift from night to night, so you needn't make the observation every single evening. Once you've got the location of the North Pole, just keep it as a reference. 'North' from any other star in the heavens is a line drawn in the direction of this Pole Star.

For Southern Hemisphere residents, the Pole Star is sigma Octantis, which isn't quite as easy to locate. I include instructions here (under Octans), but viewers of the southern stars have other, more obvious, points of repair -- the Southern Cross, Kentaurus (alpha Centauri) and Canopus.

As an example of the difficulties of not always bearing in mind just where the Pole Star is, let's take Capella as an example.
    Let us say, for instance, that it's a late November evening and Taurus has been visible for an hour or so far to the east. You want to find Capella, which is due north of El Nath (beta Tauri). But, if you haven't found the Pole Star, moving apparently "north" of El Nath would take you far afield.

    On the other hand, if you've gotten up early and are studying the stars before the sun comes up, Taurus is far to the west. Again, "north" from El Nath would take you off course.
    But once you've located the Pole Star -- or just the general point in the skies where it resides, you are ready to draw a northerly line from El Nath. On this line, north of El Nath, toward the Pole Star, you will come very quickly to Capella (which is how you find the constellation Auriga).

As pointed out in the above discussion, the circumpolar stars change quite a bit throughout the night. The same can be true for non-circumpolar stars. For example in the early evening in late November I see Orion leaning back on his right elbow, Taurus glaring down at him with his sparkling eyes (Aldebaran being the bull's right eye).
    Taurus is challenging the hunter to battle but Orion is completely disinterested. Soon however Orion slowly rises, now taking the challenge to heart. His club is now raised over his head and he threatens to attack the bull, while Taurus has shrunken back, no longer on the attack.
    They are now on equal terms and for most of the night they stare at each other as equals. But as night turns to early morning Orion has manoeuvred himself above the bull, his club ready now to come crashing down on the bull's head. Taurus has backed away, now yearning to reach the safety of the horizon before Orion decides to strike.

Night after night the drama repeats itself: first Taurus taunts the reclining hunter, then the equal stand-off, and finally Orion takes charge, threatening the retreating animal.

So you see, it depends what hour of the night you study the constellations. Thus, to make matters simpler, I will assume that the constellation under discussion will be at or near its zenith, what I've termed its 'transit'.

The 'transit' date is simply the day (or evening to be more precise) at which time the star in question will be due south of the viewer at midnight local time.

On this date, then, if you draw an imaginary line from the North Pole down to the point on the horizon that is due south, somewhere on that line will be found the star in question.

Since circumpolar stars never set (by definition), they have two transit points, an upper culmination when the stars are highest in the sky, and a lower culmination when the constellation is nearer the horizon. While you can study circumpolar constellations year round, you would probably wish to study them at or near their upper culmination, when they are highest in the sky.

For those who are not afraid of the minimal amount of mathematics, here is a short discussion on star locations.


Another brief discussion may also be useful. If you are a little hazy about what ‘magnitude’ means, this file may clear the haze.


Besides binoculars you will need some few accessories to fully enjoy the stars. The most useful accessory is a collection of star charts. These come in various guises, large and small, bound and unbound. I prefer (and recommend) Wil Tirion's Sky Atlas 2000 charts, and my examples will be based on these star charts.

A second excellent source of star charts is with the computer software called SkyGlobe. You can download a DOS version of this software (which is superb in its own right), but if you are able to register it* you'll receive a Windows version. This Windows version prints wonderful charts of whatever constellations you wish.

*The registration fee is $20 US however I understand that some of my visitors, who have tried to register this program on my recommendation, have not had any success in getting in touch with the author. It may be that the Windows version of SkyGlobe is no longer available.

Another suggestion would be to buy a Planisphere, a handy device that shows what stars are visible from your part of the world, at any time or date. These sell for $15-20 and are widely available in shops which deal with scientific and astronomical subjects. While convenient for showing what constellations will be on view at a particular date, the Planisphere isn't detailed enough to show the same multitude of stars as charts.

To use the charts with binoculars I first draw a series of rings on transparent paper. My 10x50 has a 7.5º field of vision, so I draw a circle of that size. Now when I overlay that circle on the chart everything inside the circle is exactly what I will get in my field of vision. Again, SkyGlobe is excellent for this kind of situation.

There are other accessories as well. I use a small table and chair in the backyard, and a tripod for the 10x50. To read the star charts I have a small pen light covered with a red filter so as not to interfere with night vision. And of course a thermos of hot chocolate when the nights become colder. Additional accessories include an mp3 or other music player and Wagner's Ring Cycle... (It is a profound experience, I find, to be studying the deep black skies in the middle of the night while Donner wields his hammer and the gods traipse across the heavenly bridge to Walhalla ... )

As you start to study the stars you'll soon begin to visualise them as seen through your binoculars, in relation to each other rather than individual points of light. Certain groups of stars (the Hyades in Taurus, the Big Dipper, the "W" of Cassiopeia, the Hydra's Head) will become regular signposts, from which you will jump out to other points of interest.

A special feature I employ is the frequent use of binocular views, to show you how a particular star and its surroundings will appear in binoculars. These views will show whether you've focused on the right star.

So, with this introduction, I invite you to come along and enjoy the season's constellations.

While you are free to choose from the menu which constellation you wish to learn about, sometimes I list 'prerequisites'. For example you'll find that Cepheus has the prerequisite of Cassiopeia. This simply means that you'll find your way to Cepheus considerably easier if you've first read up on Cassiopeia.

By using the information on this web site you will quickly find your way around the night skies; in no time at all you will surprise yourself at how many stars you can recognise.


To start the journey, select a constellation from the Binocular Menu.

Suggestions
Autumn -- Andromeda
Winter -- Orion
Spring -- Leo or Virgo
Summer -- Lyra

All files associated with The Constellations Web Page are © by Richard Dibon-Smith.