Pedro Castle,April 18th, 7.00 p.m. 2010

Canis Minor, as shown above on the sky chart, is a small constellation which was included in the 2nd century astronomer Ptolemy's 48 constellations, and is still included among the 88 modern constellations. Its name is Latin for "smaller dog" in contrast to Canis Major, the larger dog, and it is commonly represented as one of the dogs following the constellation of Orion the hunter

Canis Minor contains only two bright stars, Procyon, which means "before the dog" in Greek, as it rises an hour before the 'Dog Star', Sirius, of Canis Major, and Gomeisa.

Procyon is the brighter of the two. To the naked eye, it appears to be a single star, the eighth brightest in the night sky with a visual apparent magnitude of 0.34. It is actually a binary star system, consisting of a white main sequence star, named Procyon A, and a faint white dwarf companion of spectral type DA, named Procyon B. The reason for its brightness is not its intrinsic luminosity but its closeness to the Sun; at a distance of 3.5 pc or 11.41 light years, Procyon is one of our near neighbours.

Procyon forms one of the three vertices of the Winter Triangle, along with Sirius and Betelgeuse.

Procyon A is a white star of spectral type F5; it is 1.4 times the mass, twice the diameter, and 7.5 times more luminous than the Sun. It is bright for its spectral class, suggesting that it is a subgiant that has completely fused its core hydrogen into helium, and begun to expand as "burning" moves outside the core. As it continues to expand, the star will eventually swell to about 80 to 150 times its current diameter and become a red or orange color. This will probably happen within 10 to 100 million years. It is expected that the Sun will also go through this process when hydrogen fusion ceases at its core.

The chart also shows the four planets visible. Mercury might be a little hard to see on Sunday, but it has been visible for the last two weeks.

This is a list of the 20 brightest stars as seen from the Earth (not including the Sun). The stars are numbered from 1 to 20 in sequence.

	Common Name	Constellation	Apparent Magnitude	Spectral Type	Luminosity (Sun = 1)	Distance (Light Years)	Radial Velocity (km / sec)
1	Sirius	Canis Major	-1.46	A1	26	8.7	-8
2	Canopus	Carina	-0.72	F0	15,000	310	+21
3	Alpha Centauri	Centaurus	-0.04	G2	1.7	4.3	-22
4	Arcturus	Boötis	0.00	K2	115	36	-5
5	Vega	Lyra	0.03	A0	52	25	-14
6	Capella	Auriga	0.08	G8 F0	90 70	43	+30
7	Rigel	Orion	0.12	B8	60,000	910	+21
8	Procyon	Canis Minor	0.38	F5	7	11.4	-3
9	Achernar	Eridanus	0.46	B5	400	85	+19
10	Betelgeux	Orion	0.0 - 0.9	M2	105,000 v	640	+21
11	Agena	Centaurus	0.61	B1	10,000	460	-11
12	Altair	Aquila	0.77	A7	10	16.6	-26
13	Acrux	Crux Australis	0.83	B1	3,200	360	-11
14	Aldebaran	Taurus	0.85	K5	120	68	+54
15	Antares	Scorpius	0.96	M1	7,500	330	-3
16	Spica	Virgo	0.98	B1	2,100	260	+1
17	Pollux	Gemini	1.14	K0	60	36	+3
18	Fomalhaut	Piscis Australis	1.16	A3	13	22	+7
19	Deneb	Cygnus	1.25	A2	70,000	1,800	-5
20	Becrux	Crux Australis	1.25	B0	8,200	425	+20