Determination of the North Polar Distances and Proper Motion of Thirty Fixed Stars

XXII. Determination of the North Polar Distances and proper motion of thirty fixed Stars. By John Pond, Esq. Astronomer Royal, F. R. S. Read June 15, 1815. When a standard catalogue of some of the principal fixed stars was laid before the Society in the year 1813, I ventured to state as my opinion, that the error of this catalogue depending on the mechanical construction of the instrument, did not probably exceed a quarter of a second. This opinion has been confirmed by the observations of another year; the results of which I have now the honour of transmitting to the Society, as it appears that in those stars which I have continued to observe, I have not had occasion to alter the position of any one, above one-tenth of a second. For this reason I should hardly have thought it necessary to make any farther communication on the subject, had I not wished for an opportunity of adding some valuable deductions respecting the proper motions of these stars. The comparison of my own catalogue with that of Dr. Bradley in the year 1756, is shown in one of the annexed tables, (Table II.) in which the proper motions are given in the last column. I have also subjoined to my own observations the mean state of the barometer and thermometer, so that the correction may be easily made for any other table of refractions, as well as that of Bradley, which I have employed in reducing the Greenwich observations. Table III. contains, in addition to the standard catalogue, those stars which have been observed with equal care south of the equator, but from the uncertainty of refraction their positions cannot be so accurately ascertained as those of the former. In this table, the catalogue has been computed both by Bradley's and the French Tables of Refraction. I. Standard Catalogue of the North Polar Distances of thirty principal fixed Stars, reduced to the beginning of 1813. | Stars | No. of Observations in former Catalogue | Result of one year's observation N. P. D. January 1, 1813 | Total No. of Observations | Result of two year's observation N. P. D. January 1, 1813 | Mean height of barometer | Mean height of thermometer | |-------------|----------------------------------------|----------------------------------------------------------|---------------------------|----------------------------------------------------------|--------------------------|---------------------------| | Polaris | 167 | 1° 41' 21.7" | 294 | 1° 41' 21.66" | 29° 79 | 49° 6 | | β Urs. min. | 90 | 15° 4 48.9" | 120 | 15° 4 48.9" | 29° 73 | 50° 7 | | Cephei | 40 | 20° 15 30.7" | 70 | 20° 15 30.6" | 29° 77 | 49° 2 | | Urs. maj. | 60 | 27° 14 31.5" | 70 | 27° 14 31.5" | 29° 81 | 56° 0 | | Cephei | 40 | 28° 12 12.5" | 70 | 28° 12 12.5" | 29° 81 | 56° 0 | | Cassiopeia | 40 | 34° 29 22.7" | 70 | 34° 29 22.6" | 29° 81 | 56° 0 | | Urs. maj. | 48 | 35° 15 55.3" | 60 | 35° 15 55.3" | 29° 81 | 56° 0 | | Draconis | 90 | 38° 29 3.6" | 140 | 38° 29 3.6" | 29° 81 | 56° 0 | | Urs. maj. | 80 | 39° 44 57.9" | 100 | 39° 44 57.8" | 29° 81 | 56° 0 | | Persei | 40 | 40° 48 52.7" | 50 | 40° 48 52.6" | 29° 81 | 56° 0 | | Capella | 80 | 44° 12 20.5" | 110 | 44° 12 20.4" | 29° 81 | 56° 0 | | Cygni | 70 | 45° 22 56.9" | 130 | 45° 22 57.1" | 29° 81 | 56° 0 | | Lyra | 90 | 51° 23 0.5" | 170 | 51° 23 0.5" | 29° 81 | 56° 0 | | Castor | 30 | 57° 42 46.7" | 40 | 57° 42 46.7" | 29° 81 | 56° 0 | | Pollux | 40 | 61° 31 56.3" | 50 | 61° 31 56.4" | 29° 81 | 56° 0 | | Tauri | 50 | 61° 33 43.7" | 70 | 61° 33 43.7" | 29° 81 | 56° 0 | | Andromeda | 35 | 61° 56 29.6" | 35 | 61° 56 29.6" | 29° 81 | 56° 0 | | Cor. Bor. | 80 | 62° 38 55.4" | 90 | 62° 38 55.4" | 29° 81 | 56° 0 | | Arietis | 50 | 67° 25 36.5" | 80 | 67° 25 36.5" | 29° 81 | 56° 0 | | Arcturus | 80 | 69° 50 19.1" | 120 | 69° 50 19.0" | 29° 81 | 56° 0 | | Aldebaran | 56 | 73° 52 35.4" | 76 | 73° 52 35.3" | 29° 81 | 56° 0 | | Leonis | 20 | 74° 22 57.3" | 20 | 74° 22 57.3" | 29° 81 | 56° 0 | | Herculis | 50 | 75° 23 14.0" | 50 | 75° 23 14.0" | 29° 81 | 56° 0 | | Pegasi | 20 | 75° 47 51.7" | 30 | 75° 47 51.6" | 29° 81 | 56° 0 | | Regulus | 65 | 77° 7 22.7" | 65 | 77° 7 22.7" | 29° 81 | 56° 0 | | Ophiuchi | 70 | 77° 17 39.2" | 90 | 77° 17 39.1" | 29° 81 | 56° 0 | | Aquilae | 80 | 81° 36 58.8" | 140 | 81° 36 58.8" | 29° 81 | 56° 0 | | Orionis | 50 | 82° 38 15.7" | 60 | 82° 38 15.7" | 29° 81 | 56° 0 | | Serpentis | 70 | 82° 58 39.3" | 70 | 82° 58 39.3" | 29° 81 | 56° 0 | | Procyon | 40 | 84° 18 14.4" | 40 | 84° 18 14.4" | 29° 81 | 56° 0 | | Polaris SP. | | | | | | | II. Observations made with the Mural Circle, compared with the observations of Dr. Bradley in the year 1756. | Stars | N. P. D. begin. 1756 | N. P. D. begin. 1814 | Variation in 58 years | Precession in 58 years | Difference | Annual Proper Motion | |-------------|----------------------|----------------------|-----------------------|------------------------|------------|---------------------| | Polaris | | | | | | | | β Urs. min. | 14 50 47.4 | 15 5 3.6 | + 14 16.2 | 14 10.4 | 0 | + 0.100 | | β Cephei | 20 30 26.2 | 20 15 15.0 | - 15 11.2 | 15 7.7 | 3.5 | - 0.060 | | α Urs. maj. | 26 56 18.5 | 27 14 50.7 | + 18 32.2 | 18 27.3 | 4.9 | + 0.084 | | α Cephei | 28 26 27.9 | 28 11 57.6 | - 14 30.3 | 14 27.3 | 3.0 | - 0.052 | | Cassiopeia | 34 48 14.5 | 34 29 2.9 | - 19 11.6 | 19 11.7 | 0.1 | + 0.002 | | γ Urs maj. | 34 56 57.8 | 35 16 15.3 | + 19 17.5 | 19 17.2 | 0.3 | + 0.005 | | γ Draconis | 38 28 22.0 | 38 29 4.3 | + 0 42.2 | 0 | 0.1 | + 0.002 | | n Urs. maj. | 39 27 40.4 | 39 45 16.1 | + 17 35.7 | 17 33.9 | 1.8 | + 0.031 | | Persei | 41 1 47.2 | 40 48 39.2 | - 13 8.0 | 13 7.6 | 0.4 | - 0.007 | | Capella | 44 16 51.5 | 44 12 15.9 | - 4 35.6 | 4 56.4 | 20.8 | + 0.358 | | Cygni | 45 34 52.4 | 45 22 44.3 | - 12 8.1 | 12 2.8 | 5.3 | - 0.091 | | Lyrae | 51 25 47.1 | 51 22 57.4 | - 2 49.7 | 2 29.9 | 19.8 | - 0.341 | | Castor | 57 36 10.7 | 57 42 53.8 | + 6 43.1 | 6 40.7 | 2.4 | + 0.041 | | Pollux | 61 24 28.4 | 61 32 4.3 | + 7 35.9 | 7 34.1 | 1.8 | + 0.031 | | Tauri | 61 37 30.9 | 61 33 39.8 | - 3 51.1 | 3 57.9 | 6.8 | + 0.117 | | Andromedae | 62 15 27.3 | 61 56 9.6 | - 19 17.7 | 19 20.4 | 2.7 | + 0.047 | | Cor. Bor. | 62 27 0.2 | 62 39 7.9 | + 12 7.7 | 12 4.3 | 3.4 | + 0.058 | | Arietis | 67 42 12.9 | 67 25 19.1 | - 16 53.8 | 16 57.4 | 3.6 | + 0.062 | | Arcturus | 69 32 13.6 | 69 50 38.1 | + 18 24.5 | 16 30.0 | 1 | + 1.972 | | Aldebaran | 74 0 15.4 | 73 52 27.4 | - 7 48.0 | 7 53.9 | 5.9 | + 0.102 | | Leonis | 74 3 55.6 | 74 23 17.3 | + 19 21.7 | 19 15.4 | 6.3 | + 0.109 | | Herculis | 75 18 46.1 | 75 23 18.5 | + 4 32.4 | 4 36.4 | 4.0 | - 0.069 | | Pegasi | 76 10 6.0 | 75 47 32.3 | - 18 38.3 | 18 32.9 | 5.4 | - 0.093 | | Regulus | 76 51 5.1 | 77 7 40.0 | + 16 35.0 | 16 37.1 | 2.1 | - 0.036 | | Ophiuchi | 77 14 35.9 | 77 17 42.3 | + 3 6.8 | 2 56.9 | 9.5 | + 0.164 | | Aquila | 81 45 27.8 | 81 36 49.6 | - 8 38.2 | 8 11.4 | 26.8 | - 0.402 | | Orionis | 82 39 42.3 | 82 38 14.3 | - 1 28.0 | 1 23.3 | 4.7 | - 0.081 | | Serpentis | 82 47 24.7 | 82 58 51.0 | + 11 26.3 | 11 31.7 | 5.4 | - 0.093 | | Procyon | 84 10 10.3 | 84 18 21.9 | + 8 11.6 | 7 14.7 | 56.9 | + 0.681 | The N. P. D. of Polaris determined by upwards of 200 observations of Dr. Bradley, by computations made under the direction of Dr. Maskelyne, a short time before his death, and reduced to the beginning of the year By my observations for Variation in 64 years = 20 55.50 Precession for 64 years = 20 51.83 Difference = 3.67 Annual proper motion = 0.057 i.e. The annual precession, which is itself negative, must be increased by the above quantity. ### III. **North Polar Distances of forty-four principal Stars for January 1, 1813.** | Stars | With Bradley's Refraction | With the French Refraction | Annual variation | Annual Proper Motion | |----------------|----------------------------|----------------------------|------------------|----------------------| | Polaris | 1° 41' 21.6" | 1° 41' 21.6" | -19.45 | -0.057 | | β Urs. min. | 15° 4' 49.0" | 15° 4' 49.3" | +14.70 | +0.100 | | η Cephei | 20° 15' 30.6" | 20° 15' 30.9" | -15.70 | -0.060 | | α Urs. maj. | 27° 14' 31.5" | 27° 14' 31.9" | +19.30 | +0.084 | | α Cephei | 28° 12' 12.5" | 28° 12' 12.7" | -14.96 | -0.052 | | α Cassiopeiae | 34° 29' 22.7" | 34° 29' 23.1" | -19.80 | +0.002 | | γ Urs. maj. | 35° 15' 55.3" | 35° 15' 55.8" | +20.00 | +0.005 | | γ Draconis | 38° 29' 3.7" | 38° 29' 4.2" | +0.70 | +0.002 | | η Urs. maj. | 39° 44' 57.9" | 39° 44' 58.5" | +18.20 | +0.031 | | α Persei | 40° 48' 52.6" | 40° 48' 53.2" | -13.50 | -0.007 | | Capella | 44° 12' 20.5" | 44° 12' 21.1" | -4.57 | +0.358 | | α Cygni | 45° 22' 57.0" | 45° 22' 57.7" | -12.03 | -0.091 | | α Lyrae | 51° 23' 0.5" | 51° 23' 1.2" | -3.00 | -0.341 | | Castor | 57° 42' 46.7" | 57° 42' 47.5" | +7.06 | +0.041 | | Pollux | 61° 31' 56.4" | 61° 31' 57.2" | +8.00 | +0.031 | | β Tauri | 61° 33' 43.7" | 61° 33' 44.5" | -3.83 | +0.117 | | Andromedae | 61° 50' 29.6" | 61° 50' 30.3" | -19.99 | +0.047 | | Cor. Bor. | 62° 38' 55.4" | 62° 38' 56.2" | +12.49 | +0.058 | | Arietis | 67° 25' 36.5" | 67° 25' 37.2" | -17.40 | +0.062 | | Arcturus | 69° 50' 19.0" | 69° 50' 19.8" | +18.99 | +1.972 | | Aldebaran | 73° 52' 35.4" | 73° 52' 36.3" | -7.95 | +0.102 | | Leonis | 74° 22' 57.3" | 74° 22' 58.5" | +20.04 | +0.109 | | Herculis | 75° 23' 14.0" | 75° 23' 15.1" | +4.48 | -0.069 | | Pegasi | 75° 47' 51.6" | 75° 47' 52.8" | -19.43 | -0.093 | | Regulus | 75° 51' 21.0" | 75° 51' 22.3" | -20.20 | -0.084 | | Ophiuchi | 77° 7' 22.7" | 77° 7' 23.9" | +17.33 | -0.036 | | Aquila | 77° 17' 39.1" | 77° 17' 40.3" | +3.10 | +0.164 | | Orionis | 79° 50' 0.6" | 79° 50' 1.1" | -8.38 | -0.082 | | Serpentis | 81° 36' 58.8" | 81° 37' 0.0" | -9.06 | -0.462 | | Aquila | 82° 38' 15.7" | 82° 38' 16.9" | -1.37 | -0.081 | | Procyon | 84° 3' 4.1" | 84° 3' 5.8" | -8.57 | +0.391 | | Ceti | 84° 18' 14.4" | 84° 18' 15.9" | +7.55 | +0.981 | | Aquarii | 86° 39' 0.7" | 86° 39' 2.6" | -14.75 | -0.005 | | Hydræ | 91° 13' 21.6" | 91° 13' 23.8" | -17.37 | -0.106 | | Rigel | 97° 51' 11.3" | 97° 51' 13.0" | +15.19 | -0.066 | | Spica Virginis | 98° 25' 33.8" | 98° 25' 36.5" | -4.92 | -0.108 | | Capricorni | 100° 10' 51.3" | 100° 10' 54.1" | +18.95 | +0.002 | | Librae | 103° 4' 35.4" | 103° 4' 38.5" | -10.80 | -0.083 | | Sirius | 105° 12' 38.7" | 105° 12' 42.0" | +15.20 | +0.000 | | Antares | 105° 15' 22.7" | 105° 15' 26.2" | +15.20 | +0.036 | | | 106° 28' 0.7" | 106° 28' 4.2" | +4.36 | +1.158 | | | 116° 0' 16.6" | 116° 0' 22.2" | +8.62 | +0.012 |