Page images
PDF
EPUB

15′ 51′′-7, at Greenwich mean midnight 15' 48" 3; corresponding horizontal parallax 58' 12"-5, and 57' 59"-9. True distance 98° 59' 4"; distance from Nautical Almanac at III. 99° 2′ 53′′, at VI. 97° 22′ 28′′. Hour angle 17h 54m 56s W. Long. 89° 28' 30" E.

14. Sun's declination on July 4, at Greenwich mean noon 22° 56′ 37′′ N., on July 5, 22° 51′ 24′′ N.; semidiameter 15′ 45′′. True bearing N. 65° 41′ W. Variation 14° 4′ E.

15. Sun's declination on December 19, at Greenwich mean noon 23° 25′ 35′′ S.; on December 20, 23° 26′ 46′′ S. True bearing W. 31° 55' 30" S. Variation 13° 4′ 30′′ E.

16. Moon's Greenwich meridian passage June 10, 12h 2m. June 9, 11h 0m; moon's semidiameter 16' 36". Equation of time 1m S. to apparent time. High water 3h 2m A.M., and 3h 33m P.M.

NOTE. The right ascension of mean sun is found in the Nautical Almanac in page II. of each month under the heading of "Sidereal Time."

Questions.-No. II.

1. Required the course and distance from A to B.

[merged small][merged small][merged small][ocr errors][ocr errors][merged small][merged small][ocr errors][ocr errors][merged small][merged small][ocr errors][ocr errors][merged small]

2. Required the course and distance from A to B.

[merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small]

3. A ship bore from me W. & N., and a current run in the intermediate space N.N.W. 43 miles an hour; how must I steer to fetch the ship, supposing I can pull in still water 5 miles an hour?

4. May 10, 1837, at noon, a point of land in lat. 38° 17' N. and long. 56° 19′ W., bore by compass W. b. S. S. distant

17 miles (variation of compass 2 E.); afterwards sailed

as by the following log account; required the latitude and longitude in, May 11, at noon.

[graphic][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][ocr errors][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][ocr errors][ocr errors][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed]

5. What bright star will pass the meridian of Greenwich the first after 10h P.M., on October 20, 1837, and how far N. or S. of the zenith?

6. October 19, 1837, in longitude 88° 49′ E., the observed meridian altitude of the sun's lower limb was 58° 37' 56" (zenith N. of the sun); the index correction was + 8′ 38′′, and the height of the eye above the sea was 17 feet; required the latitude.

7. August 10, 1837, at 6h 40m P.M. mean time, in long. 50° 17′ E., the observed meridian altitude of the moon's lower limb was 45° 47' 39" (zenith N. of the moon), the index correction was 3′ 18′′, and the height of the eye above the sea was 24 feet; required the latitude.

8. June 3, 1837, the observed meridian altitude of the

star a Canis Majoris was 43° 29' 47" (zenith S. of the star), the index correction was 3′ 14′′, and the height of the

eye above the sea was 16 feet; required the latitude.

9. February 18, 1837, the observed meridian altitude of the star a Ursa Majoris under the North Pole was 53° 28′ 47′′, the index correction was 3' 49", and the height of the eye above the sea was 18 feet; required the latitude.

10. February 9, 1837, at 10h 20m P.M. mean time, in long. 85° 32′ W., the observed altitude of a Ursa Minoris (Polaris) was 50° 25′ 30′′, the index correction was 4' 10", and the height of the eye above the sea was 15 feet; required the latitude.

[ocr errors]

11. June 9, 1837, the following double altitude of the sun was observed.

[blocks in formation]

W.N.W.

The run of the ship in the interval was N.N.E. 5 miles, the index correction was 1′ 20′′, and the height of the eye above the sea was 17 feet; required the true latitude at the second observation; the latitude by account being 59° N. and longitude 47° 18′ E.

12. August 25, 1837, at 9h 45m P.M. in lat. 60° 2′ N. and longitude by account 59° 15′ E. when a chronometer No. 10, showed 5h 42m 16s, the observed altitude of the star a Andromeda was 39° 32′ 28′′ E. of the meridian; the index correction was + 5′ 17′′, and the height of the eye above the sea was 15 feet; required the true longitude.

On May 15, 1837, at Greenwich mean noon, No. 10 was slow on Greenwich mean time 8m 40s.5, and its daily rate was 75.8 losing.

13. May 14, 1837, at 2h 20m P.M. mean time nearly, in lat. 50° 48′ N., and longitude by account 60° 52′ E., the following lunar observation was taken.

[blocks in formation]

The height of the eye above the sea was 10 feet; required the true longitude.

14. May 20, 1837, at 4h 47m A.M. mean time nearly, in lat. 18° 42' S. and long. 160° E., the sun rose by compass E. 21° 18′ 30′′ N.; required the variation.

15. March 7, 1837, at 2h 50m P.M. mean time nearly, in lat. 51° 10' N. and long. 86° E., the compass bearing of the sun was S. 74° 42′ W.; and at the same time the observed altitude of the sun's lower limb was 21° 40′ 45′′, the index correction was 2' 18", and the height of the eye above

the sea was 14 feet; required the variation.

16. Required the time of high water at A on August 27, 1837, A.M. and P.M.

Change tide at A. 5h 18m P.M. app. time.

Long. A. 93° E.

Elements from Nautical Almanac and Answers.

1. S. 31° 43' 30" W. 344'.5.

2. E. 37'-9.

3. S.W. W.

4. Corrected courses E. b. S. S. 17'-5; S.W. b. S. 20'-7;

[merged small][ocr errors][merged small][merged small][merged small][merged small]

5. a Andromeda 23° 17′ 10′′ S. of zenith.

6. Sun's declination on October 18, at Greenwich mean noon, 9° 39′ 16′′ S.; on October 19, 10° 1' 3" S.; semidiameter 16' 5". Lat. 21° 6′ 29′′ N.

7. Moon's declination on August 10, at 3h, Greenwich mean time, 23° 15′ 12′′ S.; on August 10, at 4h.. 23° 24′ 37" S.; moon's horizontal semidiameter on August 10, at Greenwich mean noon, 15′ 43′′-8; on August 10, at Greenwich mean midnight, 15' 51" 3; correction horizontal parallax 57′ 43"-5 and 58′ 11′′.0 Lat. 20° 7′ 1′′ N.

8. Declination of a Canis Majoris 16° 29′ 49′′. S. Lat. 63° 8' 14′′ S.

9. Declination of a Ursa Majoris 62° 37′ 42′′ N. Lat. 80° 42′ 22′′ N.

10. Right ascension mean sun, on February 9, at Greenwich mean noon 21h 17m 283.28. Lat. 50° 33′ N.

11. Sun's declination on June 8, at Greenwich mean noon, 22° 51′ 58′′ N.; on June 9, 22° 57′ 10′′ N.; semidiameter 15′ 46′′. Arc (1) 81° 40′ 15′′, Arc (2) 68° 32′ 15′′, Lat. 60° 11′ 51′′ N.

Arc (3) 38° 4' 0".

12. Right ascension mean sun on August 25, at Greenwich mean noon 10h 14m 95.84; declination of a Andromeda 28° 11' 40" N. Hour angle 20h 4m 23s W. Long. 56° 15' 0". 13. Sun's declination on May 13, at Greenwich mean noon, 18° 24′ 17′′ N.; on May 14, 18° 38′ 55′′ N.; correction equation of time 3m 55.3 A. and 3m 555.9 A; moon's horizontal semidiameter on May 13, at Greenwich mean midnight, 14' 55".2; on May 14, at Greenwich mean noon, 15′ 59′′; corresponding horizontal parallax, 54' 45".1 and 54′ 58′′.9. True distance, 108° 37′ 59′′; distance at XXI, 108° 4′ 49′′; distance on 14, at Greenwich mean noon, 109° 28′ 44′′. Hour angle 2h 24m 5s. Long. 62° 15′ E.

14. Sun's declination on May 19, at Greenwich mean noon, 19° 47′ 14" N.; on May 20, 19° 59′ 54′′ N. True bearing E. 20° 59′ 45′′ N. Variation, 0° 18′ 45′′ E.

15. Sun's declination on March 6, at Greenwich mean noon, 5° 37′ 27′′ S.; on March 7, 5° 14' 8" S.; semidiameter, 16' 8". True bearing N. 130° 56′ 30′′ W. Variation, 25° 38' 30" W.

16. Moon's Greenwich meridian passage on August 27, 22h 8m.7; August 26, 21h 19m.9; moon's semidiameter, 14' 45". Equation of time 1m 19s from mean time. High water 2h 18m A.M. and 2h 42m P.M.

NOTE. The right ascension of mean sun is found in the Nautical Almanac in page II. of each month under the heading of "Sidereal Time."

N

« PreviousContinue »