Category Archives: Constellations

How to find the Winter Hexagon

Introduction

Orion is the key for
cracking the winter sky

The winter sky is an excellent place to begin exploring the constellations that make up the night sky. Orion is the key, or signpost, for locating many of the other constellations in the winter sky. There are two convenient ways to locate all of the main constellations around Orion once Orion is located. Fortunately, Orion is easy to locate and well known to most people.

The first way is to follow lines made by pairs of stars in Orion. The second way is to locate the great winter hexagon of bright star around Orion.

The Constellations of the Winter Sky

If you live in the northern latitudes and you scan the sky from the southern horizon to the region overhead, you should be able to see the following constellations on a clear winter night: Orion the Hunter, Canis Major the Great Dog, Canis Minor the Little Dog, Taurus the Bull, Auriga the Charioteer, Gemini the Twins and the Pleiades star cluster. (See the map on the next page).

 In Greek mythology, Orion was a great hunter who eventually offended the gods, especially Apollo. Apollo tricked Artemis, the Goddess of the hunt, into shooting Orion on a bet. When she discovered that she had shot Orion, she quickly lifted him to the heavens and made him immortal, where he now hunts eternally with his two dogs, Canis Major and Canis Minor. In front of him is his prey Taurus the Bull.

 The myths surrounding Auriga the Charioteer vary, but it is an ancient constellation dating back to at least to the Ancient Greeks. Some say Auriga invented the chariot and others that he trained horses for the best chariots.

 Gemini is a constellation made up of two stick figures known as the twins, Castor, who was a great horseman, and Pollux, who was a great boxer. According to one myth, Castor and Pollux (a.k.a. Polydeuces) were the sons of Zeus and Leda (from Leda and the Swan) and were hatched from an egg. Their sister was the beautiful Helen whose face launched a thousand ships to do battle in front the Trojan city of Troy.

Method 1: Using Pairs of Stars in Orion as a Guide

Finding Sirius and Canis Major

If you follow a line from the belt stars of Orion to the left and slightly down, you will come across a very bright star called Sirius, which is also known as the Dog Star. (See the arrows in the diagram to the right).

Sirius is the brightest star in the night sky so it is hard to miss. Once you’ve located Sirius you can locate the other stars in the constellation Canis Major the Great Dog.

Finding Procyon and Canis Minor

Follow the a line from the shoulder stars of Orion to the left. The first bright star that you will come close to is Procyon, which resides in Canis Minor.

From there you should be able to see the other star that us easily visible. Together, the two stars make up the constellation Canis Minor, which is also known as the Little Dog. Along with Canis Major, Canis Minor follows Orion across the heavens on an eternal hunt.

Finding Aldebaran and Taurus

Following the belt stars to the right, you will pass just below the bright star Aldebaran and through the constellation Taurus, which is also known as the Bull.

Continuing on you will run across a fuzzy blur of stars closely grouped. These are the Pleiades, or the Seven Sisters.

Finding Capella and Auriga

Follow the bottom most star on the left and the left most belt star upwards (going roughly over your head) and you will come across a very bright star called Capella. From Capella, you can follow the pentagon of brighter stars nearby that make up Auriga. Just below Capella, there is a triangle of stars known as ‘the kids’ as in goat babies.

Capella was one of the most important stars for navigation as it could be seen throughout most of the year from mid northern latitudes.

Finding the Twins Castor and Pollux

Follow a line from Rigel to Betelgeuse heading upwards and overhead. You will come to two rough sticks of stars that are headed by two brighter stars. This is the constellation Gemini, composed of the twins Pollux and Castor. Pollux is on the left and Castor is on the right.

Method 1: Using the Winter Hexagon Centered About Orion

If you look in around the sky centered on Orion, you should be able to see a rough hexagon of very bright stars. This is called the Winter Hexagon. Starting at Rigel, if you go counterclockwise by one, you end up at Aldebaran in Taurus. Go counterclockwise once more and you end up at Capella in Auriga. Go counterclockwise once more and you end up at the pair of stars Pollux and Castor in Gemini. Go counterclockwise once more and you end up at Procyon in Canis Minor. Finally, if you go counterclockwise once more you end up at Sirius in Canis Major.

Credits: http://www.science-teachers.com

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The winter hexagon v/s the summer hexagon?

Credits : Winter hexagon - Felgari

The winter hexagon is not a constellation but simply an asterism. But when there’s winter in the Northern Hemisphere, its summer in the Southern Hemisphere. I find it really unfair for the world to call this set of stars as the winter hexagon. Why don’t call it the summer hexagon? Frankly speaking I feel like being discriminated on belonging from the Southern Hemisphere.

Winter Hexagon from the Tropics

I understand that development in the astronomy field knew its leap in the Northern Hemisphere, but still I am hereby campaigning for a change in the name of this asterism ( I know Asterisms are not even officially recognized names). But the “winter hexagon” It is a complete misnomer. When I first got to see this beautiful set of constellations in its entirety by the seaside, I was feeling hot. One as it was a breezeless night, hot and damp. Secondly for the utter pleasure of being able to identify the hexagon which covered almost ¼ the portion of the sky and being able to identify six constellations in one go.  It was awesome.

But Do you Know How to find the winter hexagon?

One could ask it’s already April and the spring is already here, so why talk about the winter hexagon? It’s just because the winter hexagon in a few months would not remain in our skies. During January at dusk I would have to raise up my head towards the zenith to see the Orion as it would highlight our north western skies, but now in April it’s already halfway between the horizon and the zenith towards the west at dusk. And to tell you Scorpion is already on its way. (Hope you know about the Scorpion – Orion saga) So to say in a few months Orion would be no more on the skies. (I would miss Orion a lot)

And as April is here, it would be a lovely time to appreciate the nature in its bloom and a have good time to observe the night sky. No more shivering and complaining about the chilly weather to have a look at the sky (for my friends of the Northern Hemisphere). As for us Mauritians, we have only two seasons per se. Our hot humid summer is already gone and we are slowly entering the winter phase.

So, if you feel being discriminated by pronouncing the Winter Hexagon, (or any other misnamed constellation or asterism) then campaign with me for this misnomer. Together, united we can change the name of this marvelous hexagon to a common name. Because as the saying goes “the sky has no borders, it is for everyone”. (Is it really a saying or I just made it up?). I suppose I got it from The Astronomers without borders. They have their motto as One people, One Sky.

Related Articles:

How to find the winter hexagon

My Top 20 Guideposts in the Sky

Number

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

Explanation

Number

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

This is the name by which the star is commonly known. The names are Greek, Latin or Arabic. This web site is based in London: stars not visible from London are in red.

Some examples of the names: Deneb is Latin for tail (because it marks the tail of The Swan – Cygnus); Antares is Greek for rival of Mars (because of its red colour); Aldebaran is Arabic for eye of the bull (because it marks the eye of The Bull – Taurus).

Constellation

A constellation is a star group (as seen from Earth) that the star is a part of. Constellations are human inventions. The stars in them appear in the same part of the sky but are, in fact, at different distances from us and not related to each other. Different cultures use different constellations. For more, read Astronomy and Astrology.

In the West, there are 88 recognised constellations; 48 of these date from Roman times and are known as the Classical Constellations. These include the 12 Zodiac constellations through which the Sun, Moon and planets always pass through. Constellations are always known by their Latin names.

Some examples: Canis Major means The Great Dog; Orion is The Hunter; Crux Australis means The Southern Cross.

Constellations are used by astronomers for convenience. We say that Sirius is in Canis Major rather than give its celestial coordinates.

Apparent Magnitude

Apparent Magnitude tells how bright the star is as seen from the Earth. The magnitude scale was devised by the Ancient Greeks. The brightest stars were called First Magnitude, the next brightest were called Second Magnitude, etc.

In modern times, the scale has been defined mathematically. A star of magnitude 1 is about 2.5 times brighter than a star of magnitude 2 which in turn is 2.5 times brighter than a star of magnitude 3. The brighter a star, the smaller its magnitude. Many stars are brighter than first magnitude. Some stars are so bright they have negative magnitudes. On this scale, Jupiter has a magnitude (at its brightest) of -2.6, Venus is at -4.4 and the Sun -27. The faintest stars visible to the naked eye are sixth magnitude. Pluto has a magnitude of +14, far too faint to be visible without a powerful telescope.

In the table it can be seen that Betelgeux varies its magnitude – some stars are variable in brightness.

The brightness of a star as seen from Earth depends on its intrinsic luminosity and its distance from Earth. A dim star may appear bright because it is close while a luminous star may appear faint because it is far away. This is why we say Apparent Magnitude.

Spectral Type

When starlight is passed through a prism, it splits into its constituent colours, like a rainbow. This is called the star’s Spectrum. Stellar spectra are crossed by dark lines. These lines give astronomers a lot of information about the star: temperature, luminosity, radius, magnetic properties, movement. Read The Electromagnetic Spectrum for more on spectra.

The Morgan-Keenan spectral classification

The Morgan-Keenan spectral classification (Photo credit: Wikipedia)

Stellar spectra are classified into types. These types are given letters. The spectral type series is a temperature series. Moving from the hottest stars to the coolest, the series of letters runs O, B, A, F, G, K, M.

Each spectral type is subdivided into ten numbers. For example, A0, A1, A2, up to A9. A0 is hotter than A1. The table below gives more information.

Spectral
Type

Colour

Surface
Temperature
(°C)

O

Blue >30,000

B

Blue-White 20,000

A

White 10,000

F

Yellow-White 7,000

G

Yellow 6,000

K

Orange 4,500

M

Red 3,000

Our Sun is a star of Spectral Type G2 with a surface temperature of around 6,000°C.

Luminosity

This tells us how much more energy and light the star gives off compared with the Sun. This is how bright the star really is once distance has been taken into account. There is a huge variety in the luminosity of the stars. At one extreme, the star Alpha Centauri is 1.7 times more luminous than the Sun. At the other extreme, Canopus is 15,000 times more luminous than our Sun.

Luminosity can be measured indirectly by combining the apparent brightness of a star with its distance. It can also sometimes be measured directly from the spectrum.

Distance

The distance of a star is given in Light Years. This is the distance covered by a light beam in one year. Light travels at 300,000 km per second (186,000 miles per second). In one year a beam of light will travel 9.4 million million km (5.9 million million miles). This enormous distance is a Light Year.

Many stellar distances can be measured directly by trigonometry. As the Earth moves around the Sun, the star appears to shift its position against more distant stars. This effect is called parallax. It is a tiny effect but can be measured. The amount of the parallax depends on the diameter of the Earth’s orbit around the Sun (just under 300 million km or 186 million miles) and the distance to the star. A star with a paralax of 1 second of arc (written 1″) is said to be at a distace of 1 Parsec. 1 Parsec is equal to 3.26 Light Years.

Other stars can have their luminosity measured by their spectra or by other properties. When this is compared to their apparent brightness, a distance can be calculated.

For more on astronomical distances look at The Scale Of The Universe.

Radial Velocity

This the velocity of the star relative to the Sun. Negative velocities denote a star moving towards the Solar System. Positive velocities are for stars moving away from us.

Radial velocity is easily measured by looking at the star’s spectrum. The lines on the spectrum are shifted to the blue end if the star is moving towards us (the so-called blue shift) and to the red end if the star is moving away from us (red shift). The amount of this shift depends on the relative velocity between us and the star.

Credits: http://www.krysstal.com/brightest.html

(heavenswithlamps.wordpress.com)

100 Guide Posts in the Sky

 
The following list contains the 100 brightest stars as seen from the earth at night. The information on magnitudes is taken from data obtained by the Hipparcos Satellite Catalog. Distance measurements are from the Observer’s Handbook 2001, by The Royal Astronomical Society of Canada.

Common Name

Astronomical Name

Meaning

Apparent Magnitude

Absolute Magnitude

Distance (light-years)

1

Sirius Alpha Canis Majoris Greek: “scorching”

-1.44

1.45

9

2

Canopus Alpha Carinae Greek: pilot of the ship Argo

-0.62

-5.53

313

3

Arcturus Alpha Bootis Greek: “guardian of the bear”

-0.05

-0.31

37

4

Rigel Kentaurus Alpha Centauri Arabic: “foot of the centaur”

-0.01

4.34

4

5

Vega Alpha Lyrae Arabic: eagle or vulture

0.03

0.58

25

6

Capella Alpha Aurigae Latin: “little she-goat”

0.08

-0.48

42

7

Rigel Beta Orionis Arabic: “foot”

0.18

-6.69

773

8

Procyon Alpha Canis Minoris Greek: “before the dog”

0.40

2.68

11

9

Betelgeuse Alpha Orionis Arabic: “armpit of the great one”

0.45

-5.14

522

10

Achernar Alpha Eridani Arabic: “river’s end”

0.45

-2.77

144

11

Hadar (Agena) Beta Centauri Arabic: “ground” (Latin: “knee”)

0.61

-5.42

526

12

Altair Alpha Aquilae Arabic: “the eagle”

0.76

2.20

17

13

Acrux Alpha Crucis Greek: comb. of alpha crux

0.77

-4.19

321

14

Aldebaran Alpha Tauri Arabic: “the follower”

0.87

-0.63

65

15

Spica Alpha Virginis Latin: ear of wheat

0.98

-3.55

262

16

Antares Alpha Scorpii Greek: rival of Mars

1.06

-5.28

604

17

Pollux Beta Geminorum Greek: immortal Gemini twin brother

1.16

1.09

34

18

Formalhaut Alpha Piscis Austrini Arabic: “the mouth of the fish”

1.17

1.74

25

19

Deneb Alpha Cygni Arabic: “tail”

1.25

-8.73

1467

20

Mimosa Beta Crucis Latin: “actor”

1.25

-3.92

352

21

Regulus Alpha Leonis Greek: “little king”

1.36

-0.52

77

22

Adhara Epsilon Canis Majoris Arabic: “the virgins”

1.50

-4.10

431

23

Castor Alpha Geminorum Greek: mortal Gemini twin brother

1.58

0.59

52

24

Gacrux Gamma Crucis Greek: comb. of gamma and crux

1.59

-0.56

88

25

Shaula Lambda Scorpii Arabic: “stinger”

1.62

-5.05

359

26

Bellatrix Gamma Orionis Greek: an Amazon warrior

1.64

-2.72

243

27

Alnath Beta Tauri Arabic: “the butting one”

1.65

-1.37

131

28

Miaplacidus Beta Carinae Arabic/Latin: “peaceful waters”

1.67

-0.99

111

29

Alnilam Epsilon Orionis Arabic: “string of pearls”

1.69

-6.38

1342

30

Alnair Alpha Gruis Arabic: “the bright one”

1.73

-0.73

101

31

Alnitak Zeta Orionis Arabic: “the girdle”

1.74

-5.26

817

32

Regor Gamma Velorum unknown

1.75

-5.31

840

33

Alioth Epsilon Ursae Majoris Arabic: “the bull”

1.76

-0.21

81

34

Kaus Australis Epsilon Sagittarii Arabic/Latin: “southern part of the bow”

1.79

-1.44

145

35

Mirphak Alpha Persei Arabic: “elbow”

1.79

-4.50

592

36

Dubhe Alpha Ursae Majoris Arabic: “bear”

1.81

-1.08

124

37

Wezen Delta Canis Majoris Arabic: “weight”

1.83

-6.87

1791

38

Alkaid Eta Ursae Majoris Arabic: chief of the mourners

1.85

-0.60

101

39

Sargas Theta Scorpii Sumerian: “scorpion”

1.86

-2.75

272

40

Avior Epsilon Carinae unknown

1.86

-4.58

632

41

Menkalinan Beta Aurigae Arabic: “shoulder of the rein-holder”

1.90

-0.10

82

42

Atria Alpha Trianguli Australis Greek/English: combination of alpha and triangle

1.91

-3.62

415

43

Delta Velorum Delta Velorum Bayer designation*

1.93

-0.01

80

44

Alhena Gamma Geminorum Arabic: “the mark” on the right side of a camel’s neck

1.93

-0.60

105

45

Peacock Alpha Pavonis English: Peacock

1.94

-1.81

183

46

Polaris Alpha Ursae Minoris Latin: pole star

1.97

-3.64

431

47

Mirzam Beta Canis Majoris Arabic: “herald”

1.98

-3.95

499

48

Alphard Alpha Hydrae Arabic: “the solitary one”

1.99

-1.69

177

49

Algieba Gamma Leonis Arabic: “the forehead”

2.01

-0.92

126

50

Hamal Alpha Arietis Arabic: “lamb”

2.01

0.48

66

51

Deneb Kaitos Beta Ceti Arabic/Greek: “tail of the sea monster”

2.04

-0.30

96

52

Nunki Sigma Sagittarii ancient Babylonian name

2.05

-2.14

224

53

Merkent Theta Centauri Arabic: “in the shoulder of the centaur”

2.06

0.70

61

54

Saiph Kappa Orionis Arabic: “sword”

2.07

-4.65

815

55

Alpheratz Alpha Andromedae Arabic: “horse’s shoulder”

2.07

-0.30

97

56

Beta Gruis Beta Gruis Bayer designation*

2.07

-1.52

170

57

Mirach Beta Andromedae Arabic: “girdle”

2.07

-1.86

199

58

Kochab Beta Ursae Minoris Arabic: unknown meaning

2.07

-0.87

126

59

Rasalhague Alpha Ophiuchi Arabic: “head of the serpent-charmer”

2.08

1.30

47

60

Algol Beta Persei Arabic: “the demon’s head”

2.09

-0.18

93

61

Almaak Gamma Andromedae Arabic: type of small, predatory animal in Arabia

2.10

-3.08

355

62

Denebola Beta Leonis Arabic: “lion’s tail”

2.14

1.92

36

63

Cih Gamma Cassiopeiae Chinese: “whip”

2.15

-4.22

613

64

Muliphain Gamma Centauri Arabic: “oath”

2.20

-0.81

130

65

Naos Zeta Puppis Greek: “ship”

2.21

-5.95

1399

66

Tureis Iota Carinae Arabic: an ornament on a ship’s stern

2.21

-4.42

694

67

Alphecca (Gemma) Alpha Coronae Borealis Arabic: “bright one of the dish” (Latin: gem)

2.22

0.42

75

68

Suhail Lambda Velorum Arabic: an honorific title of respect

2.23

-3.99

573

69

Sadir Gamma Cygni Arabic: a birds breast

2.23

-6.12

522

70

Mizar Zeta Ursae Majoris Arabic: “groin”

2.23

0.33

78

71

Schedar Alpha Cassiopeiae Arabic: “beast”

2.24

-1.99

228

72

Eltanin Gamma Draconis Arabic: “the dragon’s head”

2.24

-1.04

148

73

Mintaka Delta Orionis Arabic: “belt”

2.25

-4.99

916

74

Caph Beta Cassiopeiae Arabic: “hand”

2.28

1.17

54

75

Dschubba Delta Scorpii Arabic: “forehead”

2.29

-3.16

522

76

Hao Epsilon Scorpii Chinese: “queen”

2.29

0.78

65

77

Epsilon Centauri Epsilon Centauri Bayer designation*

2.29

-3.02

376

78

Alpha Lupi Alpha Lupi Bayer designation*

2.30

-3.83

548

79

Eta Centauri Eta Centauri Bayer designation*

2.33

-2.55

308

80

Merak Beta Ursae Majoris Arabic: “flank”

2.34

0.41

79

81

Izar Epsilon Bootis Arabic: “girdle”

2.35

-1.69

210

82

Enif Epsilon Pegasi Arabic: “nose”

2.38

-4.19

672

83

Kappa Scorpii Kappa Scorpii Bayer designation*

2.39

-3.38

464

84

Ankaa Alpha Phoenicis Arabic: name of a legendary bird

2.40

0.52

77

85

Phecda Gamma Ursae Majoris Arabic: “thigh”

2.41

0.36

84

86

Sabik Eta Ophiuchi Arabic: unknown meaning

2.43

0.37

84

87

Scheat Beta Pegasi Arabic: “shin”

2.44

-1.49

199

88

Alderamin Alpha Cephei Arabic: “the right arm”

2.45

1.58

49

89

Aludra Eta Canis Majoris Arabic: “virginity”

2.45

-7.51

3196

90

Kappa Velorum Kappa Velorum Bayer designation*

2.47

-3.62

539

91

Gienah Epsilon Cygni Arabic: “wing”

2.48

0.76

72

92

Markab Alpha Pegasi Arabic: saddle

2.49

-0.67

140

93

Han Zeta Ophiuchi Chinese: an ancient feudal state in China

2.54

-3.20

458

94

Menkar Alpha Ceti Arabic: “nose”

2.54

-1.61

220

95

Alnair Zeta Centauri Arabic: “the bright one”

2.55

-2.81

384

96

Graffias Beta Scorpii Arabic(?): claws

2.56

-3.50

530

97

Zosma Delta Leonis Greek: “girdle”

2.56

1.32

58

98

Ma Wei Delta Centauri Chinese: “the horse’s tail”

2.58

-2.84

395

99

Arneb Alpha Leporis Arabic: “hare”

2.58

-5.40

1283

100

Gienah Ghurab Gamma Corvi Arabic: “right wing of the raven”

2.58

-0.94

165

* Bayer designation: names given to stars by astronomer Johanne Bayer in his 1603 star atlas Uranometria. The designations consist of a Greek letter followed by the genitive (possessive) form of the constellation name that the star is found in. They were generally named starting with the brightest star and continuing to the dimmest of any given constellation.

Eyes on the Sky: Apr 16 thru Apr 22

Eyes on the Sky: Apr 16 thru Apr 22

Catch a couple crescents and eyeing Orion

Late waning and early waxing (i.e., very thin) crescent Moons are beautiful sights, but can be tough to spot and see.  Eyes on the Sky will show you where to look in the early morning this week to see the slender waning crescent Moon in the eastern sky, then where to look again as the Moon reappears in the evening western sky.

Orion is fading into the southwestern evening sky, but still remains high enough while it is dark to spot some interesting double stars spotted with binoculars or with a small telescope.  Don’t miss the 3-D “zoom in” perspective of Orion’s belt stars, which all appear to be in a line and of equal distance – check out the surprising result of zooming in!  And lastly, with the “Mayan calendar” hype occurring, learn a bit about what the Maya saw in this part of the sky too.

Centaurus A : A beautiful Galaxy

Galaxy Centaurus A, in X-ray

Galaxy Centaurus A, in X-ray (Photo credit: Wikipedia)

Centaurus A (also known as NGC 5128) is a prominent galaxy in the constellation of Centaurus. There is considerable debate in the literature regarding the galaxy’s fundamental properties such as its Hubble type (lenticular galaxy or a giant elliptical galaxy) and distance (10-16 million light-years).NGC 5128 is one of the closest radio galaxies to Earth, so its active galactic nucleus has been extensively studied by professional astronomers. The galaxy is also the fifth brightest in the sky,making it an ideal amateur astronomy target, although the galaxy is only visible from low northern latitudes and the southern hemisphere. Credits : Wikipedia

I think  this video needs to be shared. Showing galaxies or other interesting celestial objects in multiple wavelengths is a superb job. I wonder there’s more in reserve for us by ESA.

But a deep sky object like NGC 5128 could also be seen by amateur astronomers and with the right tools and some stacking you can have a marvellous  image. What made me amazed is you could have this beautiful image with an 8″ dobsonian. ( This image is by an 8″ newtonian, but for me it’s the same) A perfect debutante telescope.

Centaurus A Gradient Removed

Credits: split_city @ http://stargazerslounge.com

First attempt at Centaurus A.

Details
Scope: 8″ Newt
Mount: EQ6
Camera: unmodded Canon 400D
ISO1600
Exposures: 25x60secs unguided
Stacked in DSS and processed in CS3

This is a cropped version. Focus slightly off and stars a little elongated.

Asterisms : What? and List

Looking up and finding patterns in the stars is a pastime that’s as old as humanity. The constellations are rich with mythology that has been passed on for millennia.

The name for these unofficial constellations is “asterism.” Like constellations, asterisms have a long history. Some are regional, (this particular asterism list  is from Germany) while others are universally recognized. Some are ancient, while others are more modern. If you enjoy stargazing, you may even have a few of your own personal asterisms. So go and be creative in the night sky and have fun.

If you are willing to find these asterisms, my advice would be to use Stellarium, if you still haven’t downloaded it, go grab it for free. you just have to type in the stars names in the Search field, for example: “delta Ori”,”epsilon Ori” and “zeta Ori”. And then you could be able to identify the asterism”the belt of Orion”. Pretty easy, huh!


Table of Asterisms:

Beehive

Located in the constellation Cancer. It is an open star cluster, which is also called Praesepe or M44 and faintly visible to the naked eye.
With the stars gamma Can and delta Can it forms another asterisms called the Asses and the Manger.

Belt of Orion

is being formed by the stars delta Ori, epsilon Ori and zeta Ori; in Latin Amerika it is called the “Three Marys”.

Bier

is being built by the four stars alpha UMa, beta UMa, gamma UMa and delta UMa.

 

Big Dipper

most famous asterism. Formed by the following Stars of the Great Bear alpha UMa, beta UMa, gamma UMa, delta UMa, epsilon UMa, zeta UMa and eta UMa, it is often called “Wain” (Wagon) or “Charles’s Wain” because of its resemblance with it when the Dipper handle is thought to be the wagon tongue.

 

Bull of Poniatowski

A T-shaped asterism just east of gamma Oph; it is formed by the stars 66 Oph, 67 Oph, 68 Oph and 70 Oph

Circlet

the western fish; the circlet is formed by gamma Psc, b Psc, theta Psc, iota Psc, 19 Psc, lambda Psc and kappa Psc.

Coalsack

Actually this is not a true asterism, but a dark patch on the Milky Way, in the constellation Crux. By the African Bushmen it was called “Old Bag”.

Frederick’s Glory

is formed by iota And, kappa And, lambda And and psi And

Guardians of the Pole

just beta UMi and gamma UMi

Head of Cetus

presented by alpha Cet, gamma Cet, xi_2 Cet, mu Cet and lambda Cet

Heavenly G

nine bright stars forming a G-shaped group. Seven of these stars are of 1st magnitude. In order they are: Aldebaran (alpha Tau), Capella (alpha Aur), Castor (alpha Gem), Pollux (beta Gem), Procyon (alpha CMi), Sirius (alpha CMa), Rigel (beta Ori), Bellatrix (gamma Ori) and Betelgeuse (alpha Ori)

Hyades

open cluster; V-shaped group superposed on alpha Tau, gamma Tau, delta Tau and epsilon Tau

Hydra Head

build by delta Hya, epsilon Hya, zeta Hya, eta Hya, rho Hya and sigma Hya

Job’s Coffin

formed by the four stars alpha Del, beta Del, gamma Del and delta Del

Keystone

is formed by the epsilon Her, zeta Her, eta Her and pi Her

Kids

are called epsilon Aur, zeta Aur and eta Aur

Lozenge

build by the four stars beta Dra, gamma Dra, xi Dra and nu Dra

Milk Dipper

The following five members of the constallation Sagittarius can be interpreted as an inverted dipper in the Milky Way: zeta Sgr, tau Sgr, sigma Sgr, phi Sgr and lambda Sgr. This asterism is also known as The Teapot.

Northern Cross

is formed by the leading stars of the constellation Cygnus: alpha Cyg, beta Cyg, gamma Cyg, delta Cyg and epsilon Cyg

Northern Fly

This is a small triangle over the rear of Aries

Pleiades

Located in the constellation Taurus. This open star cluster is one of the Messier objects, M45. It also known as Seven Sisters or, in Latin America the Seven Little Goats

Segment of Perseus

the stars eta Per, gamma Per, alpha Per, delta Per, epsilon Per and zeta Per forming an arc.

Sickle

formed by alpha Leo, eta Leo, gamma Leo, zeta Leo, mu Leo and epsilon Leo

Square of Pegasus

At the edges of that square you find alpa Peg, beta Peg, gamma Peg and alpha And

Sword of Orion

theta Ori and iota Ori; between them the famous Orion Nebula (M42) is located.

Venus Mirror

also on Orion; the belt stars (delta Ori, epsilon Ori and zeta Ori), the sword and eta Ori build up this asterism. The sword forms the handle of the diamond-shaped mirror.

Y of Aquarius

also called Water Jar; the Y is build by gamma Aqr, eta Aqr, pi Aqr and zeta Aqr

Constellations: Official List

The Constellations Table :A complete table with information about all the 88 Constellations as defined by the I.A.U. ( International Astronomical Union ). Abbreviations, Genitive and Latin Names, English Names and more.FIELD LIST

ABBREV : IAU abbreviation
CONSTELLATION : latin name
GENITIVE : latin genitive ( possessive )
ENGLISH NAME : english translation
AREA : constellation size or area, in square degrees
HEM : position in the celestial sphere :
NH – northern celestial hemisphere – declination between 0° and +90°
SH – southern celestial hemisphere – declination between 0° and – 90°
ALPHA STAR : proper name of the alpha star.

ALPHABETICAL ORDER

Cosmobrain’s Constellation Table

No. Abbrev. Constellation Genitive English Name

Area

Hem.

Alpha Star

1

And

Andromeda Andromedae Andromeda

722

NH

Alpheratz

2

Ant

Antlia Antliae Air Pump

239

SH

3

Aps

Apus Apodis Bird of Paradise

206

SH

4

Aqr

Aquarius Aquarii Water Carrier

980

SH

Sadalmelik

5

Aql

Aquila Aquilae Eagle

652

NH-SH

Altair

6

Ara

Ara Arae Altar

237

SH

7

Ari

Aries Arietis Ram

441

NH

Hamal

8

Aur

Auriga Aurigae Charioteer

657

NH

Capella

9

Boo

Bootes Bootis Herdsman

907

NH

Arcturus

10

Cae

Caelum Caeli Chisel

125

SH

11

Cam

Camelopardalis Camelopardalis Giraffe

757

NH

12

Cnc

Cancer Cancri Crab

506

NH

Acubens

13

CVn

Canes Venatici Canun Venaticorum Hunting Dogs

465

NH

Cor Caroli

14

CMa

Canis Major Canis Majoris Big Dog

380

SH

Sirius

15

CMi

Canis Minor Canis Minoris Little Dog

183

NH

Procyon

16

Cap

Capricornus Capricorni Goat ( Capricorn )

414

SH

Algedi

17

Car

Carina Carinae Keel

494

SH

Canopus

18

Cas

Cassiopeia Cassiopeiae Cassiopeia

598

NH

Schedar

19

Cen

Centaurus Centauri Centaur

1060

SH

Rigil Kentaurus

20

Cep

Cepheus Cephei Cepheus

588

SH

Alderamin

21

Cet

Cetus Ceti Whale

1231

SH

Menkar

22

Cha

Chamaleon Chamaleontis Chameleon

132

SH

23

Cir

Circinus Circini Compasses

93

SH

24

Col

Columba Columbae Dove

270

SH

Phact

25

Com

Coma Berenices Comae Berenices Berenice’s Hair

386

NH

Diadem

26

CrA

Corona Australis Coronae Australis Southern Crown

128

SH

27

CrB

Corona Borealis Coronae Borealis Northern Crown

179

NH

Alphecca

28

Crv

Corvus Corvi Crow

184

SH

Alchiba

29

Crt

Crater Crateris Cup

282

SH

Alkes

30

Cru

Crux Crucis Southern Cross

68

SH

Acrux

31

Cyg

Cygnus Cygni Swan

804

NH

Deneb

32

Del

Delphinus Delphini Dolphin

189

NH

Sualocin

33

Dor

Dorado Doradus Goldfish

179

SH

34

Dra

Draco Draconis Dragon

1083

NH

Thuban

35

Equ

Equuleus Equulei Little Horse

72

NH

Kitalpha

36

Eri

Eridanus Eridani River

1138

SH

Achernar

37

For

Fornax Fornacis Furnace

398

SH

38

Gem

Gemini Geminorum Twins

514

NH

Castor

39

Gru

Grus Gruis Crane

366

SH

Al Na’ir

40

Her

Hercules Herculis Hercules

1225

NH

Rasalgethi

41

Hor

Horologium Horologii Clock

249

SH

42

Hya

Hydra Hydrae Hydra ( Sea Serpent )

1303

SH

Alphard

43

Hyi

Hydrus Hydri Water Serpen ( male )

243

SH

44

Ind

Indus Indi Indian

294

SH

45

Lac

Lacerta Lacertae Lizard

201

NH

46

Leo

Leo Leonis Lion

947

NH

Regulus

47

LMi

Leo Minor Leonis Minoris Smaller Lion

232

NH

48

Lep

Lepus Leporis Hare

290

SH

Arneb

49

Lib

Libra Librae Balance

538

SH

Zubenelgenubi

50

Lup

Lupus Lupi Wolf

334

SH

Men

51

Lyn

Lynx Lyncis Lynx

545

NH

52

Lyr

Lyra Lyrae Lyre

286

NH

Vega

53

Men

Mensa Mensae Table

153

SH

54

Mic

Microscopium Microscopii Microscope

210

SH

55

Mon

Monoceros Monocerotis Unicorn

482

SH

56

Mus

Musca Muscae Fly

138

SH

57

Nor

Norma Normae Square

165

SH

58

Oct

Octans Octantis Octant

291

SH

59

Oph

Ophiucus Ophiuchi Serpent Holder

948

NH-SH

Rasalhague

60

Ori

Orion Orionis Orion

594

NH-SH

Betelgeuse

61

Pav

Pavo Pavonis Peacock

378

SH

Peacock

62

Peg

Pegasus Pegasi Winged Horse

1121

NH

Markab

63

Per

Perseus Persei Perseus

615

NH

Mirfak

64

Phe

Phoenix Phoenicis Phoenix

469

SH

Ankaa

65

Pic

Pictor Pictoris Easel

247

SH

66

Psc

Pisces Piscium Fishes

889

NH

Alrischa

67

PsA

Pisces Austrinus Pisces Austrini Southern Fish

245

SH

Fomalhaut

68

Pup

Puppis Puppis Stern

673

SH

69

Pyx

Pyxis Pyxidis Compass

221

SH

70

Ret

Reticulum Reticuli Reticle

114

SH

71

Sge

Sagitta Sagittae Arrow

80

NH

72

Sgr

Sagittarius Sagittarii Archer

867

SH

Rukbat

73

Sco

Scorpius Scorpii Scorpion

497

SH

Antares

74

Scl

Sculptor Sculptoris Sculptor

475

SH

75

Sct

Scutum Scuti Shield

109

SH

76

Ser

Serpens Serpentis Serpent

637

NH-SH

Unuck al Hai

77

Sex

Sextans Sextantis Sextant

314

SH

78

Tau

Taurus Tauri Bull

797

NH

Aldebaran

79

Tel

Telescopium Telescopii Telescope

252

SH

80

Tri

Triangulum Trianguli Triangle

132

NH

Ras al Mothallah

81

TrA

Triangulum Australe Trianguli Australis Southern Triangle

110

SH

Atria

82

Tuc

Tucana Tucanae Toucan

295

SH

83

UMa

Ursa Major Ursae Majoris Great Bear

1280

NH

Dubhe

84

UMi

Ursa Minor Ursae Minoris Little Bear

256

NH

Polaris

85

Vel

Vela Velorum Sails

500

SH

86

Vir

Virgo Virginis Virgin

1294

NH-SH

Spica

87

Vol

Volans Volantis Flying Fish

141

SH

88

Vul

Vulpecula Vulpeculae Fox

268

NH

BY EDUARDO SOARES

©Cosmobrain.com 2001 – All Rights Reserved.

Credits : http://www.cosmobrain.com/cosmobrain/res/constellations.html

Constellations: Origins and Now

The sky is like a grid with lots of scattered dots.  Joined together they may take many a lot of forms, depending on the whims of the sky gazer. But with these groupings known as Constellations they have helped us a lot to discover the sky.

Before the advent of the T.V, internet or the recent social medias there was a time where people used to distract themselves by observing the sky.

The sky used to marvel their souls as it was a not a stagnant beauty but the moving of the stars on the celestial plane would be their night show. After having gone through a day of accomplishment like “yeah, I conquered Rome to-day”, looking to the sky, with all its wonders would humble their beings.

We should be full of chagrin that today we are not able to appreciate and contemplate on the night sky in our urban settings. Artificial lights, though beautifying our space have barred our view of the beautiful night sky. Urbanization has given us a great wonder of man-made lighting everywhere, making our nights to become days where never ending work (24/7) has become our norm.

But……there was a time, when people had “time” to look and observe the sky. So, they grouped the stars into constellations.

Where did these constellations originate?

“Constellations are groupings of stars that, to ancient peoples, were heavenly manifestations of known or imagined objects, creatures and beings. Constellations appeared at certain times of the year, returning to those same positions annually. The ancient stargazers ascribed significance to these observations. Though identifying constellations predates the Greeks and Romans, the 48 “classical” constellation names familiar to us come from those societies.” Courtesy http://www.ehow.com/

The Greeks were creative. In fact, the constellations even today are named after the mythical beings, shapes or creatures they honored or resembled in their minds. For example, the Orion constellation takes the form of a man wielding a club and wearing a belt and a sheath.  Taurus resembles a bull’s head. And Scorpio is the Scorpion which is going to harm the man in the Orion’s constellation.  We will back  with the creative stories of the Greeks in the constellations category.

The constellations were helpful for remembering the stars, but at that time where people having loads of time in their hands would attribute the sky to several other purposes. It is common story in astronomy that farmers of the past would know about the movement of the stars and constellations in order when to sow their crops and when to harvest.  Story tellers among the Greeks would use these constellations to relate about the exploits of their Gods. And strange enough, the Egyptians had aligned their pyramids in Giza to the Orion’s belt.  The three stars in the belt as Alnitak, Alnilam and Mintaka.

Alnitak, Alnilam, Mintaka

The Arabs were the ones who preserved the astronomical science and augmented in the science so that the generations to come may take benefit from this extraordinary science. It is so interesting to know that the constellations were given Arabic names and even loads of stars got their names too. For example, In the Orion’s constellation Betelgeuse was previously yad-al-jawzaa, which later in my opinion became bad-al-jawzaa to Betelgeuse. Whereas Saiph the star, the bright star adjacent to Rigel, means The Sword. And Alnitak, Alnilam and Mintaka are Arabic too which are still called the same. Alnitak means ‘the girdle’ Alnilam, means ‘the string of pearls and Mintaka means ‘the belt’.

Then In the early twentienth century the constellations were put to an order and to the previously classical constellations other constellations were added up by  the International astronomical Union up to 88 constellations which is still in use to date. Thus the sky is now divided in these constellations, to help humanity in observing them.

“Originally the constellations were defined informally by the shapes made by their star patterns, but, as the pace of celestial discoveries quickened in the early 20th century, astronomers decided it would be helpful to have an official set of constellation boundaries. One reason was to aid in the naming of new variable stars, which brighten and fade rather than shine steadily. Such stars are named for the constellation in which they reside, so it is important to agree where one constellation ends and the next begins.”  Courtesy http://www.iau.org/public/constellations/

Obviously, these stars do not have boundaries or lines to join them when we look at them in the sky, but with the game of joining the dots, we are able to make up the lines and identify the constellations.

Further division was given to the constellations by forming patterns known as Asterisms. Well-known “constellations” such as the Big Dipper, Little Dipper, the Teapot, the Northern Cross, and the Summer Triangle are not among the official list. Some, like the Dippers and the Teapot, are actually parts of other constellations (the Big Dipper, or the great bear is part of Ursa Major, the Little Dipper is part of Ursa Minor, and the Teapot is part of Sagittarius). Others, like the Summer Triangle and Winter Hexagon, include stars from several neighboring constellations. These asterisms help us to identify the brighter stars in the constellations. If you enjoy stargazing, you may even have a few of your own personal asterisms, like I did on my entry to stargazing.

So now I have to learn 88 constellations to understand this Astronomy?

Ahhh…..Kinda yes. If you want to be familiar with the sky then you have to know the stars and the constellations. But it is a marvelous, jaw- dropping adventure which you will never regret. And learning along is the great thing.

Yeah, but still I have to learn 88 constellations?

Rome was not conquered in one day. Learning the sky can be done step by step. You learn it by loving it. No rush for a certificate, no rush for schooling, just you and the stars. Finding Betelgeuse in Orion would be pretty easy. But also knowing that it is classified as a red supergiant, Betelgeuse is one of the largest and most luminous stars known. In terms of mass, Betelgeuse is thought to be about 15 times the mass of the sun, but 600 times wider and more than 200 million times its volume! Though it looks tiny but it is not what you are thinking……. Isn’t the study of stars cool?

Found our star, the sun?

Stay tuned, there is more to come.

 

 

 

 

 

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