Philosophical transactions, Vol. L. Part I. For the year 1757.: Giving some account of the present undertakings, studies, and labours, of the ingenious, in many considerable parts of the world.Various
History
Philosophical transactions, Vol. L. Part I. For the year 1757.: Giving some account of the present undertakings, studies, and labours, of the ingenious, in many considerable parts of the world.
Various
Science -- Periodicals
October 4ᵈ 17ʰ 0’ _d_ Leonis (whose right ascension was 162° 0’ 15"
and declination 4° 54’ 57" north) preceded the Comet 40’ 15” in right
ascension, and was more southerly 20’ 53". Hence the Comet’s right
ascension was 162° 40’ 30" and its declination 5° 15’ 50" north.
October 7ᵈ 16ʰ 54’ the 79th Leonis in the British Catalogue (whose
right ascension was 167° 53’ 37" and declination 2° 44’ 15" north)
followed the Comet 13’ 0" in right ascension, and was more northerly
38’ 35". Hence the Comet’s right ascension was 167° 40’ 37" and its
declination 2° 5’ 40" north.
October 8ᵈ 16ʰ 53’ the Comet preceded _v_ Leonis 1° 53’ 30" in right
ascension, and was 37’ 20" more northerly. The right ascension of this
star was 171° 7’ 45" and its declination 0° 30’ 55" north; therefore
the Comet’s right ascension was 169° 14’ 15" and its declination 1° 8’
15" north.
October 11ᵈ 16ʰ 52’ the Comet followed _v_ Leonis 2° 33’ 30" in right
ascension, and appeared 1° 55’ 5" more southerly; but it being near the
horizon, the difference of right ascension must have been contracted by
refraction about 1’ 5", and the difference of declination about 1’ 30":
so that the corrected right ascension of the Comet was 173° 42’ 20" and
its declination 1° 25’ 40" south.
Immediately after this observation a fog arose, which prevented me from
repeating it; and several mornings following proving hazy or cloudy,
I could not see the Comet again till October 18th, about an hour and
a quarter before sun-rising; when the twilight being strong, and the
Comet low, it appeared very faint. However, I was unwilling to omit
the opportunity of determining its place, as near as I could, by a
single observation, in the following manner.
At 6ʰ 59’ 54" ½ sidereal time, I observed the passage of the Comet
over the perpendicular wire of my equatorial Sector; then leaving the
instrument in the same position till the next evening, I observed, that
at 22ʰ 8’ 15" sidereal time, the 17th star of Eridanus in the British
Catalogue passed over the same wire (or horary circle) 9’ 30" more
southerly than the Comet. And at 23ʰ 45’ 36" sidereal time the star
marked _b_ in Eridanus passed, 19’ 55" more northerly than the Comet.
I found that the situation of my instrument was not sensibly altered
between the 18th and 19th of October; for the transits and the
difference of declination of the same stars being observed with it
again on the 19th of October, they agreed very well with those that
were taken the preceding night. It may therefore be supposed, that the
position of the instrument continued the same likewise during the time
of the foregoing observations.
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