1918.] The: N.Z. Journal of Science and Technology. 231 
magnitudes 2 and 7, 3 and 8, &c. The diagram shows the relation between 
magnitudes and brightness. The magnitudes are shown along the lower 
edge of the diagram, from 1 to 6, &c., to the right, and from 1 to 0, and 
to —1 and —2, to the left. The scale of brightness is shown on the left- 
hand side, from 0 at the base, and increasing upwards. 
From the definition it follows that the light of a first-magnitude star 
is approximately 2*512 times the light of a second-magnitude star, and 
a similar relation holds between any two consecutive magnitudes. Hence, 
if the magnitude scale is continued to the left, a star of 0 magnitude will 
be 2*512 times as bright as a star of the first. magnitude, a star of —1 
magnitude will be 2*512 times as bright as a star of 0 magnitude, &c. The 
star Canopus is of —0*9 magnitude, and it will be seen from the diagram 
that Canopus is 5*6 times as bright as a first-magnitude star, while Sirius, 
of magnitude —1*6, is 11*0 times as bright as a first-magnitude star. On 
the same scale the magnitude of the full Moon is about —12, and of the 
Sun — 26*7. 
The list of the twenty brightest stars, in order of the magnitudes as 
given in the British Nautical Almanac, contains the names of the stars, the 
magnitudes, the spectra, and the positions for 1920*0. The brightness of 
any star may be obtained from the diagram by reading the height corre¬ 
sponding to the magnitude. 
The Bright Stars. 
Name of 
Star. 
Magnitude. 
i 
; Spectrum. 
| 
R.A. 
1920 0. 
Dec. 
1920*0. 
h. 
m. 
s. 
O 
/ 
a Canis Majoris, 
Sirius 
-1*6 
Ao 
6 
41 
37 
-16 
36 
a Argils, 
Canopus 
-0*9 
Fo 
6 
22 
10 
-52 
39 
a Lyrae, 
a Aurigae, 
Vega 
0*1 
Ao 
18 
34 
14 
+38 
43 
Capella 
0*2 
Go 
5 
10 
47 
+45 
55 
a Bootis, 
Arcturus 
0*2 
Ko 
14 
12 
1 
+19 
36 
a Centauri 
• o • • 
0*3 
Go 
14 
34 
10 
-60 
30 
13 Orionis, 
Rigel 
0*3 
B8 
5 
10 
42 
- 8 
18 
a Canis Minoris, 
Procyon 
0*5 
F5 
7 
35 
7 - 
+ 5 
26 
a Eridani, 
Achernar 
0*6 
Bo 
1 
34 
44 
-57 
39 
d Centauri 
0*9 
B1 
13 
58 
10 
-59 
59 
a Aquilae, 
Altair 
0*9 
A5 
19 
46 
53 
+ 8 
39 
a Orionis 
Betelgeuse . . 
1*0 to 1*4 
Ma 
5 
50 
50 
+ 7 
24 
a Crucis 
1*1 
B1 
12 
22 
9 
-62 
39 
a Tauri, 
Aldebaran 
M 
K5 
4 
31 
20 
+ 16 
21 
d Geminorum, 
Pollux 
1*2 
Ko 
7 
40 
25 
+28 
13 
a Virginis, 
Spica 
1*2 
B2 
13 
20 
59 
-10 
45 
a Scorpii, 
Antares 
1*2 
Ma 
16 
24 
30 
-26 
15 
a Piscis Australis, 
Fomalhaut .. 
1*3 
A3 
22 
53 
14 
-30 
3 
a Cygni, 
Deneb 
1*3 
A2 
20 
38 
42 
+45 
0 
a Leonis, 
Regulus 
1*3 
B8 
10 
4 
7 
+ 12 
21 
Nova Aquilae. 
The discovery of the new star in the constellation Aquila was reported to 
the Government Astronomer (1) by Mr. G. V. Hudson, of Karori, Welling¬ 
ton ; (2) by Mr. Alex. G. Crust, of Dunedin ; (3) by Sergeant-major L. J. 
Comrie, on active service. 
