MEAN TIME OF TRANSIT (AT WASHINGTON) AND POLAR DISTANCE OF POLARIS. From June 16 to August 1 both the upper and lower transits take place during daylight. The azimuth at the time of greatest Eastern or Western elongation can be easily computed from the formula: sin A = where A denotes the azimuth, p the polar distance, and the latitude of the place. DATE OF GREATEST ELONGATION. To find the time of greatest Eastern or Western elongation, let I denote the hour angle, and / and p as before, then we shall have And the hour angle in mean time is cos F= tan p tan 1. Ilm x 0.0664846. This quantity, Hm, added to or subtracted from the time of transit given above, according to the elongation required, will give the mean time of the greatest elongation at any place whose north latitude is 1. -1 18 0 +10 40, 0 a Leonis (Regulus). aAndromed(Alpher'z) + 28 36 28 14+6 16.6 +18 14.6 Aquarii Declination On Meridian. Upper. Lower. 0 I H. M. H. M. +12 248 40.1 +20 38.1 -10 42 +11 56, 523 54.5 +19 38 +13 47.5 +0 45.5 +74 31 +13 27.5+1 25, 5 +27 113 497 1 47.7 -26 14 14 59. 3 2 57.3 +88 42 17 9 3 5 7.3 +8 38+18 21. 4 6 19 4 58 +19 13. 5+ 7 11.5 13 +19 51, 5 + 7 49.5 -0 45 +20 35.88 33. 8 30 521 27.1 +9 25.1 +14 4421 34.7 + 9 32.7 To find the time of the star's transit add or subtract, according to the sign, the numbers in the second column of figures to the date of the transit of the pole star given above. Thus, for a Andromeda February 1, Lower Transit of Pole Star is 4 h. 45 m. 48. A. M. to which add 10 h 40 m. and we have 3 h. 25 m. 4s. P. M.; for December 1, we find 7 h. 31 m. 22s. P. M., etc. APPROXIMATE PARALLAX AND DISTANCE IN LIGHT-YEARS OF SOME OF THE PRINCIPAL FIXED STARS. By light-years is to be understood the number of years light requires to travel from the star to us. The determination of stellar parallax is one of the most difficult and refined problems in practical or observational astronomy. It is to find the angle which the semi-diameter of the earth's orbit subtends at the star-an angle always very small, as seen from the above table, and which cannot be measured directly, but by various processes too complicated to be explained here. Astronomical Phenomena for the Year 1914. Astronomical Phenomena for the Year 1914. 55 Two heavenly bodies are in conjunction' (6) when they have the same Right Ascension, or are on the same meridian, i. e., when one is due north or south of the other; if the bodies are near each other as seen from the earth, they will rise and set at the same time; they are in "opposition (8) when in opposite quarters of the heavens, or when one rises just as the other is setting. "Quadrature (□) is half way between conjunction and opposition. By greatest elongation is meant the greatest apparent angular distance from the sun; the planet is then generally most favorably situated for observation. Mercury can only be seen with the naked eye at this time. When a planet is in its ascending" (2) or "descending'' (U)node it is crossing the plane of the earth's orbit. The term "Perihelion means nearest, and Aphelion" furthest, from the sun. An occultation" of a planet or star is an eclipse of it by some other body, usually the moon. 1.-ECLIPSES. In the year 1914 there will be four eclipses, two of the sun and two of the moon, as follows: 1. An annular eclipse of the sun February 24, Invisible in North America, visible as a very small partial eclipse in the southern part of Patagonia and the eastern coast of New Zealand. The path of the annulus lies wholly in the Antarctic and South Pacific Oceans. 2. A partial eclipse of the moon March 11-12, visible in the United States. 3. A total eclipse of the sun August 20-21, visible as a small partial eclipse in eastern portion of Canada and the northeastern part of the United States. The eclipse will not be visible west or south of a line drawn through or near Rapid City, Manitoba; Devil's Lake and Fargo, N. Dak.; Redwood Falis, Minn.: Peoria, Ill.: Indianapolis, Ind.; Harrisonburg, Va., and Washington, D. C. The first contact of the penumbra with the earth takes place in the middle of James's Bay (the southern part of Hudson Bay), and the last on the east coast of Africa, about four degrees north of the equator. The path of the total eclipse begins at sunrise in the Arctic Ocean, lat. 71°.4 and long. 121°.2 W. It moves northeast and then east. crosses Northern Greenland and then southeast, passing north of Jan Mayen (Arctic Ocean), crosses the North Atlantic and the middle of Norway and Sweden, the north end of the Baltic Sea, enters Russla, passing almost directly over Kleff, crosses the east end of the Black Sea, traverses eastern Turkey in Asia, Persia and ends at sunset near Lahkpat in Western India, lat. 23°.75 N. and long. 70°.6 E., having traversed 191°.8 of longitude. The greatest duration of totality is 2 minutes and 14 seconds, which occurs in Russia, lat. 54° 9′ N. and long. 27° 18' E. In Western Ohio and the eastern shore of Michigan, the middle of the eclipse will take place at sunrise. The dates of beginning and ending for the following places in the United States and Canada are given below. The position angles are reckoned from the north point of sun's limb. 4. A partial eclipse of the moon, September 3-4, Invisible in the United States east of the Rocky Mountains. At San Francisco the eclipse will begin September 4, 4h. 6.6m. A.M.; at Los Angeles, 4h. 23.3m. A.M., the moon setting with the eclipse on it. 56 Astronomical Phenomena for the Year 1914. ASTRONOMICAL PHENOMENA FOR THE YEAR 1914.-Continued. II.-A TRANSIT OF MERCURY. There will be a transit of Mercury over the sun's disk November 7, partly visible in the eastern portions of the United States and the Dominion of Canada, the sun rising with the planet on it. Last Inter'r Contact. Last Ex. Con. H. M. PLACES. Last Inter'r Contact. Last Ex. Con. H. M. PLACES. D. H. M. St.John's, N.F. Nov. 7 10 36.8 A.M.10 38.9 A.M.Charleston. Que bec.. 7 9 22.6 A.M. 9 24.8 A.M.New Orleans. 9 11.6 A.M. 9 13.8 A.M.St. Louis. 1.3 A.M. Houston. Toronto. 7 8 49.9 A.M. 8 52.0 A.M.Denver. N The angle of position at the last external contact is 105°.2 from the north point of the sun's 11mb toward the west. The nearest approach of the centres of the sun and planet is 10' 31"-about two-thirds of sun's semidiameter. The motion of the planet is retrograde, that is to say, from east to west or from left to right as we stand facing the sun. The accompanying diagram represents the position of the planet on the sun's disk shortly after sunrise as seen from New York, but it will serve with sufficient accuracy for the mere purpose of observation, for all other places in the above list. HO represents the horizon, NS a portion of a meridian through the sun's centre. and A B the direction of the planet's motion. All the dates in the eclipses and in the transit of Mercury are given in local mean time. DATE The Sun's Right Ascension and Declination. The Sun's Right Ascension and Declination. Apparent 1914. (WASHINGTON-APPARENT NOON.) 34.81 35.89 58.78 21.16 43.01 4.30 25.02 45.16 4.69 23.59 85 59.47 16.42-20 32.67 48.21 17.14 30.50 43.10 54.92 -19 21 22 16.19-18 48.96-17 4.76-16 14.10-15 13.80 12.44-14 10.28 7.33 3.62-13 59.16 48.02 -12 41.38 46777 Apparent 23132 214 54321 2 I2222222223 May 3 431 4 2233 June 23.2 55.3 19.8 7 37.3 48.4 6 10 54.13 5 47 36.43 24 18.31 0 40.92 2.12 42.26 22 12 41.11 20.29 59.29 42 42531 11222 00 00 00 4 ++ |