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LONGITUDE AND TIME.
if performing correctly, when comparing it with the clocks at both of these places?
3. Are the clocks of the following places faster or slower than those of London, and how much:-Petersburg-Cape Town - Philadelphia-Barbadoes-St. Helena-Madras-Batavia-Otaheite ?
4. Each day of the year differs from the day which precedes it with respect to the period at which any fixed star appears on the meridian. On the night of 28th January, Sirius (the Dog Star) comes to the meridians of the following places when their clocks are striking ten: what hours will the clocks of London be showing at these several instants?-Vienna-New York-Calcutta-Lisbon-Dublin-Port Royal, (Jamaica).
To find the Latitude in which a certain Star rises or sets at the instant that another certain Star is culminating.
Repeat the following:-
Sidereal Day, (def. 83); Astronomical and Civil Reckoning, (def. 82); Right Ascension, (def. 52); Sidereal Clock. (def. 53).
RULE.-Bring the star given as culminating to the brass meridian, and elevate or depress the pole until the other star coincides with the eastern or western part of the horizon. Then the number of degrees on the brass meridian from the elevated pole to the horizon, will show the latitude. N.B. It is important to take the point in the centre of the star's rays for the star's place.
1. In what latitude did I observe Arcturus on the meridian, when Antares (a of Scorpio) was rising?
Here, by bringing Arcturus to the brass meridian, and arranging the poles until Antares is coinciding with the eastern part of the horizon, I find that declination 60° N. is in the zenith; and that, consequently, the North Pole is elevated 60°.
2. When a of Lyra (Vega) is on the meridian, Algol (of Perseus) is rising, what is the latitude?
Altair (a of Aquila) on the meridian, 8 of Leo Major setting, what is the latitude?
Fomalhaut (of Piscis Australis) on the meri
dian, Rigel rising, what is the latitude?
a of Crux on the meridian, a of Columba set
ting, what is the latitude?
Sirius (a of Canis Major) culminating, a of Virgo (Spica) rising, what is the latitude.
7. On the 18th of September, the sun appears at a point in the heavens which is scarcely one degree south of B of Virgo in what latitude will Aldebaran set at noon on that day?
8. On the 28th May, Aldebaran comes to the meridian with the sun. It happened to be full moon exactly at noon of this day at Bath: what was the latitude in which Regulus (in the Lion's heart) was rising at that instant, and how was the moon situated where Regulus was setting instead of rising? (See question 9 of Prob. XI.)
To find a place having its Latitude and Longitude given.
Repeat the following:
Right Sphere, (def. 49); Parallel Sphere, (def. 50); Oblique Sphere, (def. 51); Oblique Ascension, (def. 54); Oblique Descen sion, (def. 55).
RULE.-Follow the directions respecting the arrangements of the Globe, and the proper use of the right or left hand, in Problem II. Place the thumb nail upon the
LATITUDE AND LONGITUDE.
given latitude, and bring the given longitude to the brass meridian; then under the given latitude will be the place required.
Conversely. If a given place be brought (with the right or left hand according to its north or south position) to coincide with the brass meridian, the latitude will be found over the place; and the longitude, or inclination of the plane of its meridian to the east or west of that of London, will be cut by the brass meridian on the Equator.
Find the places answering to the following latitudes and longitudes :
Having a given Star, to find what other Stars lie in the same plane with that Star and the two poles of the Equinoctial, and consequently with the whole axis of our earth.
Repeat the following:
Equinoctial, (def. 14); Examine, by the Globe, the List of Constellations, (pages 55-58). Repeat again, Greek Alphabet, (p. 24.)
RULE.-Make the poles of the Equinoctial coincide with the wooden circle of the globe, and bring the given star to the graduated surface of the brass meridian; then all stars coinciding with the brass meridian will be the stars required.
Note. The stars coinciding with the under semi-circle of the brass meridian are also in the same plane; but may, in this instance, be left unnoticed.
1. What remarkable star in Ursa Minor; what stars in Cassiopeia, Pegasus, the Phoenix, and Hydrus, are nearly in the same plane with a of Andromeda and the Polar points; and, consequently, in the same plane with our whole axis ?
By bringing a of Andromeda, which I find to be in the head of that Constellation, to coincide with the graduated edge of the brass meridian, I see that the Pole Star, (which is not at the Pole), is then just 110 above it; and that ẞ in the chair of Cassiopeia, y (Algenib) in the wing of Pegasus, e in the wing of the Phoenix, and 8 in Hydrus, are likewise on the meridian.
2. What stars in Andromeda, Triangulum, Pisces, Cetus,* Eridanus, and Hydrus, are in the same meridional plane at any instant, with a in the Head of Aries?
3. What stars in Perseus, Sceptrum, Eridanus, and Dorados, are in the same plane with Aldebaran; and how is that plane numbered where it cuts the Equinoctial?
4. What stars in Auriga, Lepus, and Columba, are brought to any meridian at the same time with Betelgeux, (a of Orion) and how is their common plane numbered on the Equinoctial?
5. What small stars in the Lynx, Gemini, Monoceros, and Argo Navis culminate at the same instant, (or within two minutes of time, or a half degree), with a of Canis Major, (Sirius)?
6. What stars in Ursa Major, Leo Minor, Leo Major, and
* If the globe should not have the smaller stars marked with sufficient clearness, the exact part of the Constellation may be named.
RIGHT ASCENSION AND DECLINATION.
Argo Navis, are on my meridian, at the same time every day, with a of Hydra, (Cor Hydræ); and how is the plane passing through them marked on the equinoctial?
7. When the Southern Pointers," a and y of Crux, are on the meridian of any place, what stars in Musca Australis, Corvus, Coma Bernices, and Draco are culminating; and what point of the equinoctial is culminating with them all?
8. When n of Boötes is on the meridian, what star in the Great Bear's Tail, what little star in Virgo, and what considerable star in Centaurus, are likewise very nearly on the meridian ?
9. What stars in Ursa Minor, in Draco, in Corona Borealis, in Serpens, in Lupus, and in Triangulum Australe, are on the meridian with y of Libra; and what point of the equinoctial culminates with them?
10. What three stars in Hercules, what stars in Serpentarius, and what two remarkable stars in Ara, culminate every day about 5 minutes before S of Draco ?*
11. What stars in Draco, Cygnus, Sagittarius, and Pavo, come to the meridian with a of Aquila (Altair); and what degree of the equinoctial ?
12. What degree of the equinoctial, and what small stars in Cepheus, Pegasus, Aquarius, and Grus, culminate every day with a of Piscis Australis, (or “ Fomalhaut" ) ?
To find a star, or any heavenly body, having its Right Ascension and Declination given.
Conversely. Having a star, &c., given, to find its R. A. and Declination.
Repeat the following:
Sidereal Clock, (def. 53); Magnitude of a Star, (def. 5); Aberration, (def. 103); Nebula, (def. 106); Galaxy, (def. 107.)
* Near the pole of the Ecliptic, and just preceding it; i, e. westward of it.