The sextant is a mathematical instrument by which the different degrees of longitude and latitude are determined, and the hour known.
All observations with the sextant {9} were out of the question until we were once more some degrees from the zenith.
From the observatory with a sextant he made an observation every six hours, making allowance for the declination of the sun, meantime.
Mitchell and Duval took the sextant readings at face value.
The seven reductions are each calculated from two sextant readings, generally of an upper and lower limb.
Five or ten minutes before local noon the observer levels his artificial horizon and with sextant in hand lies down on the snow.
Such an image cannot be recorded on a sextantwith sufficient accuracy to make it of any use as an observation.
By showing them a sextantand other apparatus he learned that I not only had a full set, but he also learned how I used them.
Not one of one hundred thousand honest sextant experts would credit such an observation as that upon which Mr. Peary's case rests--not even in home regions, where for centuries tables for corrections have been gathered.
These sextant readings of the sun's altitude were continued for the next twenty-four hours.
Several sextant observations gave a latitude a few seconds below 90 deg.
About five minutes before local noon the sea captain goes to the bridge withsextant in hand.
Then the captain looks through his sextant at the moon, or at some bright star, and finds his position that way.
Then the captain goes down into the cabin and does some arithmetic out of a book, using the things that his sextant had told him, and he finds just exactly where the ship was at noon of that day.
And sometimes it is cloudy for several days together, so that he can't take an observation with his sextant in all that time.
Why Sextant when we dye Its only coz we cant brethe no more--that's all.
O Sextant of the meetinouse which sweeps And dusts, or is supposed to!
The local attraction was so great on this hill that the prismatic compass was useless; luckily I had my pocket sextant with me, by which I obtained the included angles.
The natives were still with us; they seemed inquisitive and cunning; and shewed great surprise at a sextant and artificial horizon, by which they sat down, attentively watching what was done.
The sextant and artificial horizon, lying on the ground, escaped destruction, and the dipping-needle had fortunately been taken on board.
Those who had loads which would not be hurt by tumbling about among bushes, travelled on; but, having the chronometer and a sextant to take care of, I waited till one of the men returned with a lantern.
He brought out a damaged leathern trunk, with two or three shirts, and other articles of dress, much the worse for wear, and the sextant and parchment already mentioned.
I made use of the spirit level, as the horizon was invisible and the sextant could therefore not be used.
With their help, and that of a cloud horizon that was clearly defined in the moonlight, not far below our level, I used the sextant to fix our position.
My sextant was of the ordinary marine type, but it had a more heavily engraved scale than is usual, so as to make easier the reading of it amid the vibration of the aeroplane.
There may be, also, an error inherent in the sextant itself.
Upon examining my sextant I found the index error was 39 degrees 1 minute.
Yesterday I discovered that I had not repaired my sextant in a satisfactory manner.
The sun is too vertical for taking it with mysextant and artificial horizon.
I have got a sextant for taking the latitude, but I have not a chronometer, as Mr. Gregory thought the jolting it would get should render it useless.
At this period of our journey the sextant was too much out of order for making sufficiently accurate observations of the stars.
The sextant and circle had been the property of Dunbar, and were acquired from him by Governor Gayoso.
With a Haddley's sextant he determined the latitude of that place, and he also made a sketch of the river.
It had been raining during the night and the day was dull and cold, so I stayed in camp to write up my notes and compute some sextant observations, and sent off two parties of men to hunt through the forest for ruins.
That evening I said good night to my host early, as I had some writing to do, and later on spent an hour or two shooting stars with a sextant and working out our position.
Mr. Bayley's sextant was stolen from the observatory: Cook at once demanded from the chiefs that it should be returned, but they paid no attention.
I had to abandon at that spot all the unused photographic plates, my sextant and a large prismatic compass, half the supply of cartridges we had taken with us, a pair of extra shoes, and a number of other things.
My men were greatly excited, saying it was an Indian who had come quite close to me, and was about to shoot an arrow while I was busy with my sextant and chronometers.
I generally took a great many sights with the sextant and artificial horizon, in order to define the latitude and longitude with greater accuracy.
I needed this man and his companion to carry my sextant and the unexposed photographic plates, some two hundred of them, which were of considerable weight.
At noon the officers, sextant in hand, waited in vain for an opportunity of "shooting the sun.
Here is a sextant and a bundle of charts, however," he added.
A skin is then thrown down on the snow close to the box and north of it, and the observer lies down flat on his stomach on this, with his head to the south, and head and sextant close to the artificial horizon.
He rests both elbows on the snow, holding the sextant firmly in both hands, and moving his head and the instrument until the image or part of the image of the sun is seen reflected on the surface of the mercury.
A single observation at sea with sextant and the natural horizon, as usually taken by the master of a ship, is assumed under ordinary satisfactory conditions to give the observer's position within about a mile.
Explorers naturally select hills as their points of triangulation; but compass observations on hill-tops, if unchecked by a sextant observation of the sun's bearings, are never so reliable as those taken on a plain.
I find that a capital substitute for a very rude sextant is afforded by the outstretched hand and arm.
The use of the sextant may be learnt at various establishments in the City and East End of London, where the junior officers of merchant vessels receive instruction at small cost.
On my right was a sextantto take the distance between the moon and the lunar stars that were in position.
On my left was the sextant for taking altitudes, near which was the slate with pencil to write down the figures, and the bull's-eye lantern was lighted to help me to read the sextant.
Soon after he left the Pole, the sextant that he was using slid off the chart table, breaking the horizon glass.
He had developed a sextant by which the altitude of the sun could be gaged without reference to the horizon line, and that was exactly what he needed now, because due to the formations of ice, the horizon was irregular.
Flying blind that way, they had to depend upon their sextant to keep their course, and Anne Lindbergh did her part by using this.
With the oil fast spurting out, and the motor threatening to stop any minute, and nosextant to show his position, Byrd had his hands full.
But figuring out position by means of thesextant requires at least an hour of mathematical calculation, and by the time the position had been figured, the men in the airplane had advanced about a hundred miles or more.
Travelling thus, with the aid of his compass, sextant and sketch maps, he reached Mansarowar.
Only one reading there in the Congregational Church, where there was such a fearful lack of ventilation that I turned from my manuscript and quoted a bit from the "Apele for Are to the Sextant of the Old Brick Meetinouse by A.
High noon, and a red spot visible overhead; the captain brings out hissextant to take an observation.
This proceeding we viewed with no little interest, and, for the humor of the thing, I borrowed the sextant of the captain and took a satirical view of a great luminary in obscurity.
The sextant having been broken to pieces, I had no means of ascertaining the position of this island, nor do I now know anything of it except that it lay, in the month of August, within the region of the southeast trade winds.
A single horizontal angle taken with a sextantbetween objects, as two lighthouses, defines the position of the vessel as somewhere on the circumference of a circle passing through the two objects and the vessel.
This method as well as any use of sextant angles or bearings depends of course on the accuracy of the chart, and caution must be used where it is not certain that the chart depends upon an accurate survey.
A single sextant angle furnishes a means of avoiding a known danger by using what is known as the horizontal "danger angle.
The vertical angle is measured with a sextant and must be the angle at the ship between the top of the object and the sea level vertically beneath it; for a hill or mountain, therefore, the eye of the observer should be near the water.
A system of sounding lines is then run over the entire area to be surveyed, locating the position of the sounding boat at intervals by sextant angles on survey signals or by angles from the shore.
The use of thesextant seems to have been forgotten after this time; for Tycho Brahe is said to have re-invented it, and to have employed it for measuring the distances of the planets from the stars.
