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24 "THE. MarRINE. REVIEW NAUTICAL ASTRONOMY SIMPLIFIED. Some Useful and Interesting Facts About Polaris and the Big Dipper. PREFACE; THE OBJECT OF THIS: ARTICLE IS TO CALL THE ATTENTION OF LAKE CAPTAINS AND OTHERS TO THE USEFULNESS OF OBSERV- ING FOR AZIMUTHS, OBSERVING STARS FOR AZIMUTHS IN ASCERTAINING THE DE- VIATION OF THE COMPASS, OR IN SETTING THE COURSE, CANNOT BE TOO STRONGLY REC- OMMENDED. IT IS OF INESTIMABLE VALUE TO KNOW HOW TO USE THE STARS FOR AZIMUTH PURPOSES. THE SUN MAY BE OVER-CLOUDED FOR SEVERAL DAYS WITH CLEAR NIGHTS SO THAT THE STARS READILY AFFORD A MEANS OF FINDING THE DEVIA- TION AT ANY HOUR OF THE NIGHT, THE SAME AS USING THE SUN DURING THE DAY. THE STARS CAN BE USED FOR THIS PURPOSE ALMOST AS EASILY AS THE SUN, THERE BE- ING ONLY A FEW ADDITIONAL POINTS TO KNOW AND BEAR IN MIND, THE MOON CAN BE USED IN THE SAME MANNER. THE CAPTAIN OF TODAY (ON ACCOUNT OF THE PECULIAR BUILD OF LAKE BOATS) CANNOT MAKE COURSES IN CLOUDY WEATHER SINCE IT IS ALMOST NECESSARY FOR HIM TO RELY | SOLELY ON AZIMUTHS OF THE SUN FOR EVERY COURSE HE STEERS, THE STARS THEN WOULD PROVE OF THE GREATEST VALUE. TO "HIM, SINCE IT INVARIABLY HAPPENS THAT A CLOUDY DAY BRINGS FORTH A CLEAR NIGHT. THERE ARE MASTERS WHO WILL LOOK ON THIS ARTICLE WITH SUSPICION, AND THEY WILL SAY TO THEMSELVES THAT IT IS TOO HEAVY FOR' THEM. RIGHT HERE IS WHERE THEY ARE MISTAKEN, THIS SUBJECT IS NOT BEYOND THE ATTAINMENTS OF THE AVERAGE LAKE MASTER AND HE SHOULD NOT BE SATISFIED WITH HIMSELF UNTIL HE HAS MASTERED IT. HOW TO FIND THE STARS WILL BE EXPLAINED IN ANOTHER PA- PER. IT IS NECESSARY TO UNDERSTAND WHAT IS EXPLAINED IN THE FOLLOWING ARTICLE BEFORE "STAR FINDING" CAN BE ACCOMPLISHED WITH ANY DEGREE OF SATIS" FACTION. THE NORTH STAR OR POLE STAR. Of all stars the North Star is prob- ably the most useful to the navigator of the northern hemisphere. This is be- cause it is practically stationary in the northern sky, its orbit. of revolution be- ing so small that any motion of the star is made imperceptible to the casual ob- seryer. All the other stars appear to move, and keep changing their positions and bearings, much like that of the sun. Not so with the North Star, it will always be found in the northern sky practically in the same place. It is for this reason that it is the mariner's unerring guide, and many a disaster has been averted by BY CLARENCE E, LONG. its timely bearing, and many is the lost traveler who has. regained his reckoning from this star. at roost." This remarkable feature of the North Star affords the standard by which all terrestrial directions are determined, for it is only necessary to get a bearing of this star on any clear night to establish the true north or the true meridian of any place. No other celestial body af- fords this simple means of determining actual directions. Little or no calcula- tion is required to use the north star in this respect, whereas, with all other stars, also the moon and the sun, require com- ptutations more or less difficult. The earth's rotation and the rising sun afford us the direction of east, but only twice * a ee N x ' x es °. ° i . + . ic 5 PoEa eS i mo A ee es goa % Roe ee f som © ee ; a a ys SA oes & Ae ae : Kos : in the year (at the equinoxes) does the sun rise exactly in the east. It is there- fore more cenvenient and much more reliable, to reckon direction from the north, which' can .be accurately deter- mined by observations of the North Star, or Polaris, a fixed star situated almost directly over the north pole, and, there- fore, a true index of north. |: For this reason it is often called the Pole Star. This star is of course only visible at places north of the equator, and can be found any clear night by reference to two stars, called "the pointers,' in the con- stellation of "The Big Dipper." Twice during every 24 hours the Pole Star is at its greatest angle from the true north pole of the heavens, called celestial pole. This greatest. angle is but 1° 11'. At all other times it is less than this, and twice in 24 hours it bears true north--once when above, and once when below the true pole. In other words, the star bears true north when it intercepts the pole (called 'above ithe pole) and true north when it is in- tercepted by the pole (called below the pole). From the above it will be appreciated that the star never varies more than the eleventh part of one compass point from _ ter plough, dipper, etc. the true north, therefore it is safe to consider the star as indicating the true pole of the heavens, for it would require fine manipulation to detect a variation at any time. In astronomy this star is referred to as Ursa Minoris, and before it became the pole star it was known as Ruccabah. the. Dipper, which affords an_ infallible guide to the pole star by means of the two "pointers," is in the constellation of Ursa Majoris, and the Pole: Star is in the tail of the Little Dipper or Little Bear. Ursa Minoris means the Little Bear, also referred to as Ursa. Minor; Ursa Majoris «(Ursa Major). means Great Bear. : The Great Bear or Big Dipper, as: it is best known, is a constellation remark- able for its conspicuousness, and it is due to this fact that it is so easily found. The figure formed by its seven principal stars is variously termed--the Plough, the Skillet, the Cleaver, the Dipper, the Wagon, and Charles's Wain. This con- stellation is more deserving of such names than that of "Great Bear." That this constellation looked like a great bear to the ancients is beyond the comprehen- sion of we of today. The observer of today finds it impossible to trace in the sky the various figures which groups. of stars were supposed to represent by the astronomers of the olden time. The Great Bear has an impossible tail for a bear. Who ever heard of a bear having a tail longer than its body. Therefore, the Great Bear makes an infinitely bet- While most peo- ° ple would absolutely fail to recognize such fanciful images' as the crow, the eagle, the whale, the dog, the ship, the ram, the lion, the dove, the swan, the crane, the sea serpent, the fish, the scor- pion; the giant, the virgin, and a hun- dred or more others, equally as ridicu- lous, but they could not help but perceive, on the most casual inspection, that cer- tain star groups had forms, mostly geom- etrical, of some kind or another. This being so, it is more satisfactory and much more convenient, to know them as some such figure. For this reason it is better at once 'to: chuck these fantastic figures as so much imaginary rubbish. The Big Dipper is composed of seven stars of nearly equal brightness, and this is what renders it so easily recognized by the learner. over The star at the extreme end of the han- dle of the Big Dipper is named Be- netnasch. The two at the opposite, or