287
ASTRONOMY.
. .—- -=
the Moon ’s.semidiurnal arc at 9h. 21m. 29s. without regard tore- ;fraction. From tins we find I6h.' 46m. 29s. — 7h. 30m. 27s. = 19h. 16m. 2s. for the Moon ’s rising very nearly.
- Third ArrROxiMvriON. 12 hours : 71': : 9h. 16m. 2s. : 54'50.''; and 16° 5' + (54' 50" -{- 9' 50", on account o( the inequality :of motion hr declination in 24, hours) — 17° 9'40". The tabularascensional dilfevence corresponding to this is 22° 50' 39", in partsof the ecliptic, or lh. 31m. 23s. in time. And l6h. 46m. 29s. — ;(lh. 31m. 23s -)- 6h.) = 9h. 15m. 6s. tire correct time of the .Moon ’s rising without having regard cither to parallax or refrac- jtion. Now to obtain the combined effect of refraction and paral- jlax in this case, there must be given the latitude of the place, 51° ;28' 40”, the declination of the' Moon , 17° 9' 40", the horizontal;refraction, 33' 30", the Moon ’s horizontal parallax, 59' 24". 1and the difference of the parallax and refraction, 25' 54“, which:
! in time is 107",6. From these data work by logarithms as below :
j (See Art. 92, page 283.)
| Logarithm-cosine of (i -j- d) 68° 38' 20".9,5613933
Logarithm-cosine of (/ — d) 34° 19'.9,9169455
Slim... } ,.2)9,4783333
Half the sum.9,7391694
Which subtract from the logarithm of 107",6.2,0318123
And the remainder is the log. of 196", or 3m. 16s.3,2926429
This quantity added to 9h. 15m. 6s. because the parallax is greattTthan the refraction, and the rising consequently retarded, the sum9h. 18m.'22s. is the correct time of the Moon ’s apparent rising re-quired.
(94.) The following is a Table of the Names, Magnitudes, Right Ascensions in Time, and Declinations, of ike principal fixed Stars , to-gether with their annual Differences in Right Ascension and Declination; us also their Semidiurnal Arcs for the Latitude ofLondon, and Bai/cr’s literal Characters, the whole exactly adapted to the beginning of 1810. By means of this Table, pro-vided the Sun’s' Right Ascension be known, the Time of the Rising, Southing, and Setting, of any Star contained in it may befound for any Turt qf the Globe, by attending to the Instructions laid down in the preceding Pages.
No.
Names and Places of the Stars .
Bayer’s Ch.
a
bC
rt
3
Right As-censionJan.1,1810.
Annual
variat. in
right Ascen.
Declination,Jan. 1, 1810.
An. var.
in Declin.
Semidiufor L
Real.
rnal Areondon.
Apparent.
1
Extremity of Pegasus’s left wing, (Algenib).
y
2
H. M. S.
0 3 28
sec.
-3,07
0 t H
U 7 30 N
It
+20,05
H. M. S.
7 13 47
H. M. S.
7 17 40
2
In the Whale’s tail.
i
3
0 o 32
-3,09
9 5.3 21 S.
-20,00
5 9 22
5 13 5
3
In the head of the Phoenix.
C6
2
0 16 32
-3,00
43 19 48 S.
-20,00
Rises not.
Rises not.
4
in the constellation of Andromeda .
s
3
0 29 11
-3,16
29 4S 40 N
4-20,01
9 4 21
9 10 24
5
In the breast of Cassiopeia.
a
• 2
0 29 48
1-3,31
55 29 43 N
+ 19,91
Sets not.
Setsnot.
6
Whale’s tail.;.
0
<2
0 33 42
-3,01
19 1 54 S.
-19,86
4 17 15
4 21 25
7
In the girdle of Cassiopeia.
y
3
0 45 20
+3,49
59 41 9 N.
+ 19.71
Sets not.
Setsnot.
8
In the extremity of the Little Bear’stail, (Pole-star)
a
3
0 54 25
-0,84
SS 17 41 N.
+ 19,60
Sets not.
Sets not.
9
In the body of the Whale.
n
3
0 59 2
-3,01
11 11 27 S.
-19,45
5 2 24
5 6 9
10
0
2
0 59 8
-3,30
34 30 39 N
+ 19,45
10 0 44
10 9 30
11
In the right thigh of Cassiopeia.
»
3
1 13 27
+3,75
59 15 2 N.
+ 19,12
Sets not.
Sets not.
12
In the body of the Whale.
In the spring of the river Frida, (Achernar).
9
3
1 14 33
+3,01
9 9 48 S.
-19,07
5 13 18
5 16 55
13
a
1
1 30 38
+2,25
58 21 35 S.
- IS,55
Rises not.
Rises not.
14
In the right leg ofCassiopeia.
t
3
1 40 51
-
-4,14
62 43 46 N.
-18,27
Sets not.
Sets not.
15
In the horn of the Ram.
r>
3
1 44 10
-3,28
19 52 35 N.
-18,10
7 48 7
7 52 26
16
ct
3
1 52 14
-3,09
1 50 29 N.
-17,80
6 9 15
6 12 51
17
Andromeda ’s left foot, (Almach)...
2
1 52 17
-3,62
41 24 48 N.
-17,70
Sets not.
Sets not.
18
In the Ram's following horn.
ct
2
1 56 29
-3,33
22 33 37N.
-17.60
8 5 56
8 10 33
19
In the neck of the Whale, (a variable star)...-..
0
2
2 10 34
-3,03
3 50 35 S.
-17,04
5 40 37
5 44 13
20
In the Whale’s lower jaw'.
s
3
2 29 43
-3,07
0 29 50 S.
-16,00
5 57 30
6 1 5
21
In the breast of the Whale.
3
2 30 23
-2,89
12 40 49 S.
-16,02
4 54 19
4 58 7
on
In the mouth of the Whale.
3
2 33 29
-
-3,11
‘j a 5 33 !N.
-J-15,80
6 12 15
6 15 51
23 •
In the right paw of tiie Whale.
7T
3
2 35 6
-2,86
14 40 7 S.
-13,77
4 43 11
4 47 4
24
In the river Lridanus .
>1
3
2 47 9
-2,93
9 39 23 S.
-15, JO
5 10 34
5 14 18
25
in the right shoulder of Perseus .
y
3
2 51 7
L 4,24
52 44 12 N.
+ 14,93
Sets not.
Sets not.
26
In the Whale’s upper jaw, (Menkar).
a
2
2 52 22
-3,12
3 20 29 N.
+ 14,76
6 16 51
6 20 28
27
In the head of Medusa , (Algol, a variable star)...
£
o
2 55 51
-3,85
40 12 56 N.
+ 14,63
Sets not.
Sets not.
28
In the river Kridanus.
12
3
3 3 59
+2,53
29 45 9 S.
14,07
2 56 33
3 2 17
29
In the river Kridanus .i.
K
3
3 6 37
+2,91
9 31 57 S.
13,92
5 11 15
5 14 58 '
30
In the right side of Perseus , (Algenib').
2
3 10 49
+4,20
49 10 35N.
Sets not.
Sets not.
31
In the belly of Perseus.
s
3
3 29 27
+4,20
47 10 14N.
4-12,49
Sets iut.
Sets not.
32
Brightest of the Pleiades .
3
3 36 12
+3,54
23 30 35 N.
•L 11,90
8 12 "8
8 17. 22
33
In the river Kridanus .
y
2
3 49 10
+*,80
14 3 17 S.
11,01
4 46 40
4 50 31
34
In the nose of the Bull.
y
3
4 9 0
+- >39
15 9 39 N.
+ 9,60
7 19 40
7 23 36
35
In the left eve of the Bull.
t
3
4 17 32
+ 3,48
IS 41 59N.
+ 8,90
7 41 2
7 45 14
36
Bull’s right eve, (Aldebaran) .
ct
1
4 25 2
+3,42
16 7 10N.
+ 8,‘<?6
7 25 14
7 29 14
37
hi the river Kridanus.
h
3
4 58 32
+2,95
5 20 21 S.
5,53
5 33 0
5 36 37
38
Auriga’s left shoulder, (Capella).
ct
1
5 2 38
+ 4,37
45 47 44 N.
4- 5,'31
Sets not.
Sets not.
39
Orion’s left foot, Rigel .
1
5 5 24
+2,87
S 25 45 S.
4,88
5 17 2
5 20 44
40
Bull’s north horn.
2
5 14 17
+.3,77
28 26 14N.
+ 4,19
8 51 39
8 57 13
41
Orion’s left shoulder, (Bellatius) .
y
2
5 14 58
+3,22
6 10 6 N.
-j- 4,15
6 31 14
6 34 53
42
In the Hare’s right fore-paw.
3
5 20 8
+2,5S
20 55 1 S.
3,66
4 5 11
4 9 32
43
In the girdle of Orion.
s
2
5 22 19
+3,07
0 26 55 S.
3,50
5 57 44
6 1 19
44
At the extremity of the Bull’s south horn .
C
3
5 26 18
+ 3,59
21 1 2N.
+ 3,20
7 55 32
7 59 57
45
Middle star in Orion's girdle .
f
2
5 26 34 +3,04
1 19 57 S.
3,00
5 53 19
5 56 53
46
In Noah’s dove .
ct
2
5 32 48 j+2,18
34 10 53 S.
2,48
2 5 30
2 13 36
47
At the extremity of the Hare’s right liind-paw —
y
3
5 36 35 l-|-2,53
22 30 56 S.
2,23
3 54 26
3.5.8:58