First of all, what is a constellation?
Basically, a constellation, including the Microscopium Constellation, is a group of Stars. To expand a little, it is an area on the celestial sphere (an imaginary sphere) where a group of visible stars are located.
These stars typically form a pattern or outline, which we perceive to represent an inanimate object, (scientific instruments like the microscope or weighing scales, an animal (like the she-goat) a mythical person (like Zeus, the Hero Perseus, King Cepheus and Queen Cassiopeia and their daughter Andromeda or even a type of creature (like Pegasus, the winged-horse, Medusa, or Cetus, the Sea Monster), from Greek mythology.
It is also an astronomy term used to describe a variety of groups of stars that have been given a specific name such as –
FACT: The ecliptic is the imaginary line tracing the route that The Sun, the Moon, and the Planets take across the sky, over the year.
Constellations are constantly moving and move in the direction from East to West.
The Microscopium Constellation – Facts in brief:
What is it? –
The Constellation Microscopium is a minor Constellation located in the Southern Hemisphere.
The name ‘Microscopium’ is Latin for ‘the Microscope’.
The Microscopium Constellation is regarded as one of the smaller and unremarkable constellations.
Who named it?
Microscopium is one of the 12 Constellations created by the French astronomer Nicolas-Louis de Lacaille in the 18th Century.
The Constellation of Microscopium is a member of the Lacaille family of Constellations named by Nicolas Louis de Lacaille.
The 12 Constellations in the Lacaille family includes:
- Antila; Caelum; Circinus; Fornax; Horologium; Mensa; Norma; Pictor; Reticulum; Sculptor and Telescopium
Microscopium is also one of the official International Astronomical Union (IAU) listed 88 modern constellations as seen in the night sky from Earth . It is listed as the 66th largest Constellation overall, filling around 0.5% of the night sky.
Microscopium (its Latin name), or its abbreviation ‘Mic’, is used in connection with the Constellation. It is quite easy to recognize, as it resembles the outline of a classic scientific instrument – ‘the compound microscope’
Where is it located? –
The Constellation of Microscopium is positioned in the fourth quadrant of the Southern Hemisphere, south of the celestial equator.
It is sometimes referred to as being located in the SQ4 Quadrant.
The Microscopium Constellation is located quite far away from the Milky Way.
It is not a circumpolar Constellation as it is only visible for part of the year in Southern latitudes, but the best month to view it at its best is July.
It is barely visible from the majority of the non-tropical Northern Hemisphere.
The Circumpolar Constellations
There are 5 Constellations that are visible throughout the year, from most locations located north of the celestial equator, making them Circumpolar, they are:
- Cassiopeia Constellation
- Cepheus Constellation
- Draco Constellation
- Ursa Major Constellation
- Ursa Minor Constellation
FACT: A constellation that is visible all year round is known as a Circumpolar Constellation.
There are 3 Southern Constellations that are also circumpolar –
Where can it be seen?
Co-ordinates of a right ascension, or left ascension and their declination are used to locate all of the Constellations, like Microscopium.
The Constellation of Microscopium is small with a faint level of luminosity that is most visible in theSouthern Hemisphere, between July and September.
The Constellation of Microscopium lies at 21-hours right ascension and a Declination of 35 degrees South.
It’s more easily visible from the Southern Hemisphere at latitudes between +45 degrees and -90 degrees and covers an area of 210 square degrees in the southern sky.
Microscopium is hard to see from Northern latitudes.
Meet The Neighbors
The Microscopium Constellation is bordered by several other Constellations:
- Capricornus – to the North
- Indus and Telescopium – to the South
- Sagittarius – to the West
- Piscis Austrinus and Grus – to the East
It is most visible in the Southern Hemisphere during the summer months, in the evening around 21.00 hours.
How can you identify the Constellation of Microscopium?
The simplest method for spotting any particular Constellation from Earth is to first of all locate the brightest star in that Constellation, and then look at the neighboring illuminations, to see if you can identify a recognizable pattern.
There are not many very bright stars located within the Constellation of Microscopium.
In fact the brightest Stars in Microscopium are only fifth level visual magnitude Stars and at this level of luminosity they are not easily visible by naked eye (best seen with the help of binoculars).
Naming the Stars in a Constellation
The main Stars in a Constellation are often designated a name from whoever discovered them or the person who first listed them.
The bright Stars in any Constellation are listed in order of luminosity from the brightest Star to the faintest Star and sometimes allocated a proper name or a letter or number.
In the Bayer Star designations, The ‘Alpha’ letter is normally allocated to the brightest star, then ‘Beta’ and so on in decreasing order through the letters of the Greek alphabet.
- In the Constellation of Microscopium, the brightest Star is called Gamma Microscopii, but it has only has an apparent magnitude of 4.68. It is located 381 light years from Earth.
- The second brightest Starin Microscopium is known as Epsilon Microscopii, with an apparent magnitude of 4.72 and located 182 light years from Earth.
- There are 5 Stars that make up the outline of the Microscopium Constellation.
- Gamma Microscopii (y Mic) – a Yellow Giant Star
- Epsilon Microscopii (e Mic) – a White Dwarf Star
- Theta 1 Microscopii (Nu Mic) – a wide Double Star
- Alpha Microscopii (a Mic) – a Yellow Giant Star
- Iota Microscopii (i Mic) – a Yellow-White Dwarf Star
The Microscopium Constellation can be identifiedin the night sky as a polygon with four segments.
While Microscopium, is often connected with this image it is also represented in other ways, such as the ‘microscope’.
The brightest stars are dim and difficult to see from Earth, by the naked eye.
The Star System within Microscopium
The Constellation of Microscopium has about 5 main Stars making up the imaginary outline of a scientific instrument, like a microscope.
The bright stars that form the shape of ‘the microscope’, listed from brightest Star to fainter stars are:
- Gamma Microscopii (y Mic) – a variable Star System, 2 binary stars
- Epsilon Microscopii (e Mic) – a single white-hued Star
- Theta 1 Microscopii (θ Mic) – a suspected binary Star System
- Alpha Microscopii (a Mic) – a single Star
- Iota Microscopii (i Mic) – a suspected astrometric binary Star System
- Nu Microscopii (v Mic, originally Nu Indi from Constellation Indus) – an orange-hued variable Star System
- Microscopii (y Mic) – a variable Star System, 2 binary stars
- 2 Piscis Austrini (HR 8076) – a single Star
- HD 210772 – a Star
- Zeta Microscopii (Z Mic) – a yellow-white hued Star
The Stars within Microscopium that have been approved by the International Astronomical Union (IAU) use the recommended three letter abbreviation ‘Mic”
There are no formally named Stars in the Constellation of Microscopium.
Location of Microscopium
Microscopium can be spotted in the Southern Hemisphere, also referred to as the Southern celestial sky.
The Constellations surrounding Microscopium are easier to recognize and spot in a dark night sky as they have a brighter apparent magnitude, and are used as a guide-point in the sky used by astronomers and amateur stargazers to identify certain Deep Sky objects.
When to see the Constellation Microscopium?
The word ‘Microscopium’ is actually from the Latin language meaning ’Microscope’.
The Constellation of Microscopium is not one of the original 48 Constellations catalogued by Ptolemy, although it is one of the 88 Constellations listed in the official IAU chart published by the International Astronomical Union (IAU).
It fills an area of 210 square degrees.
- Initially, the shapes of their star patterns informally categorized the Constellations in the sky.
- Eventually, the IAU published the official listing of constellation boundaries. This maps the constellations by their sky coordinates not by the line patterns and shapes they are referred to by.
The outline of Microscopium
The shape of the original compound microscope from the 18th century intrigued Nicolas Louis de Lacaille, the well-known French astronomer.
He imagined this shape from the position of the 5 main Stars in this Constellation, and so he named this Constellation ‘Microscopium’ in honor of the invention of the microscope, at that time.
You will have to use your imagination using the following Stars as part of the outline of this asterism.
- Gamma Microscopii, Epsilon Microscopii, Theta 1 Microscopii, Alpha Microscopii and Iota Microscopii
The constellation of Microscopium is sometimes described as an object that looks like a tube above a square box.
Within the Microscopium Constellation?
The Constellations are formed by of a number of different components.
The different components housed by most Constellationsare mainly Stars, Deep Sky Objects and Messier objects (galaxies).
The Microscopium Constellation contains:
- 5 main Stars
- 2 stars that host an exoplanet
- 13 Bayer/ Flamsteed Designated Stars
- 1 associated minor meteor shower, known as the ‘Microscopids Meteor Shower’
- 0 Messier Objects
There are many different types of Stars in the star system categorized by size, lifespan and luminosity.
Generally, larger Stars have a shorter lifespan.
Stars are formed from clouds of interstellar gas and include:
Red Dwarf Stars
Most of the stars in the galaxy are Red Dwarf Stars. They are small in size measuring about 40-50% of the mass of The Sun. They are cool and their luminosity has only about 10% of the brightness of the Sun (our brightest Star), and they live for longer.
Brown Dwarf Stars
These are known as failed stars that form like other stars but don’t reach the mass, heat or density to begin the nuclear fusion process. They are only about 8% of the mass of the Sun and are red not brown, and not easy to spot in the night sky.
Red Giant Stars
These are giant luminous stars that have a low or medium mass. A Red Giant Star is formed when a star expands its volume by fusing all of its hydrogen into helium, and then burning the helium to produce carbon and oxygen to expand.
These are giant, bright stars that range from 10-100 times the size of the Sun and are 1000 times brighter. They are big and hot and therefore burn out quickly. The biggest are called Blue super giants or hyper giants. The biggest ever discovered was about 10 million times brighter than the Sun,
These are main-sequence stars like the Sun, but only 80% of its size, and are bright stars,
These are small burnt out husks of stars, about the same size as the Earth. White Dwarfs are dense and represent the final state of evolution for a star, like most stars in the galaxy.
These are the remains of a White Dwarf after it cools and darkens. This is likely to happen after about 10 billion years of life.
These are also main-sequence stars like the Sun, but twice the size, and are bright stars and hot.
Other types of stars include the Orange Giant, Neutron stars, Variable Stars and Binary Stars
Other types of stars include Neutron stars, Variable Stars, Binary Stars and some particularly interesting Stars such as:
The Star – Lacaille 8760 (AX Microscopii)
This Star was originally discovered by French astronomer Nicolas Louis de Lacaille, from the Cape of Good Hope in South Africa, around 1750, and is one of the largest and brightest Red Dwarf Stars.
Lacaille 8760 (ax Microscopii) is a Red Dwarf Star, within Constellation Microscopium, is one of the closest Stars to the Sun.
It is not a bright Star as it has an apparent visual magnitude of +6.7 and too faint to be visible by the naked eye.
This Star is classified as a Flare Star that erupts less than once a day on average.
The Star – Au Microscopii
Au Microscopii is a Red Dwarf Star that is also a Variable Star.
It hosts a Neptune-sized planet and has an amazing circumstellar disk of dust surrounding it. This is known as a ‘debris disk’.
FACT: the debris in space comes from the collision of asteroids, comets and little planets as they swirl around the stars. From earth we can see the light reflected from interplanetary dust.
Au Microscopii is part of the Beta Pictoris Moving Group, which is a group of young moving Stars that are similar in their origin and the way they move through space. This Star is relatively close to Earth being located around 32.5 light years from our Solar System.
The Au Microscopii Star is faint as it has an apparent visual magnitude of 8.73.
The Star – WASP-7
WASP–7 (also designated HD 197286)is an F-type Star thatappears to host a dense planet, known as a ‘hot Jupiter’. It is known as a hot Jupiter as it has a similar mass to the well-known Jupiter planet in our solar system.
WASP-7 has an apparent visual magnitude of 9.5 and is located approximately 520 light years from Earth. As it is located close to its hot parent Star it generates enough heat to shine in the sky. It has a radius of around 123% and a mass of 128% of our Sun.
The Star – Bo Microscopii
Bo Microscopii is one of the most active Stars located close to the Sun.
It is a fast spinning Star known as ‘Speedy Mic’ with an apparent visual magnitude of 9.39.
Bo Microscopii is classified as being a ‘Flare Star’, as it generates impromptu increases in X-ray emissions and ultraviolet emissions.
This fast moving Star is located approximately 218 light years from Earth and has around 82% of the mass, and 106% of the radius of the Sun.
Other notable Stars in the Constellation of Microscopium are:
a Red Giant Star, located around 2.700 light years away and 444 times brighter than the Sun
a Binary Star System, with 2 Red Dwarf Flare Stars, that are located around 35 light years from Earth, with impromptu boosts in brightness.
The R Microscopii Binary star system has a combined visual magnitude of around 11, and both are smaller and cooler than the Sun.
What is a Bright Star?
The sky is home to various bright stars.
The brightness of a star is measured by a value called its magnitude (apparent visual magnitude) and they come in different sizes, composition, mass and color.
The brightest Stars that make up the Constellation of Microscopium are 5th magnitude Stars, and the brightest only has an apparent magnitude of 4,67 and is best seen with the aid of binoculars.
Their vast distance away from us is measured in light years from the Earth, the Sun or even the Milky Way. The lower the magnitude value the brighter the star appears in the night sky when viewed from Earth.
The Microscopium Constellation also has deep sky objects and galaxies (or even globular clusters or open clusters).
Deep Sky Objects
The Constellation of Microscopium has very few deep sky objects.
The best time to see the Stars and Deep Sky Objects within Microscopium is in the month of September. Most are too faint to be seen by the naked eye and would need binoculars of a telescope.
Deep sky objects include objects from the Messier New General Catalogue (abbreviation is NGC).
NGC 6925 is an unbarred spiral galaxy, not in the Solar System. It’s positioned 3.7 degrees west/north-west of the Alpha Microscopii Star. It is shaped like a lens and has an apparent magnitude of 11.3.
NGC 6923 is a barred spiral galaxy positioned in Microscopium.
FACT: A Deep Sky Object is an astronomical object that is not a part of the solar system like the Sun, Moon, Comet or a Planet.
An individual Star is not considered to be a Deep Sky Object.
Deep Sky Objects are faint objects that can still be observed by the naked eye in the night sky from Earth.
Deep Sky Objects include Galaxies, Star Clusters and Nebulae.
- Star clusters – such as Globular Clusters of Stars or Open Clusters of Stars
- Dark Nebula, Planetary Nebula, Diffuse Nebula, and Supernova remnants
- Galaxy Groups, Galaxies, Gravitational Lenses and Quasars.
What is a Nebula?
A Nebula is a massive cloud of gas and dust in Space.
Some Nebulae are formed when a star explodes and then dies, like a Supernova. Sometimes they can act as Star nurseries and are the areas where new Stars are forming.
The Nebulae are the spaces in between the stars referred to as interstellar space.
There are several types of Nebulae:
- Bright Nebulae,
- Emission Nebulae,
- Reflection Nebulae,
- Dark Nebulae
- Planetary Nebulae
FACT: a ‘reflection nebula’ is an interstellar cloud that should be a dark nebula (a molecular cloud) however its dust reflects light from a nearby bright star and it reflects the light, hence the name.
Images of Nebulae have been captured using professional Space telescopes, such as the NASA Spitzer Space Telescope, operated by NASA, and the famous Hubble Space Telescope.
Microscopium is often abbreviated to ‘Micr’ from a naming convention used by NASA.
What is a Messier?
A Messier is a cluster of Stars
It was Charles Messier, a French astronomer, who is credited with cataloging each of the Messier Star clusters, around 1764.
He is famous for publishing an astronomical catalogue that lists 110 nebulae and star clusters, known as the New General Catalogue (used in its abbreviated form NGC and numbered).
These later became known as the Messier objects.
There are no Messier objects in Microscopium
FACT: A star cluster is a large group of Stars that can be Globular Clusters or Open Clusters:
- Globular Clusters:
A global cluster is a spherical collection of ‘Old Stars,’ numbering hundreds to millions, that are tightly bound by gravity and orbits a galactic core.
- Open Clusters:
An open Cluster is a looser formation of ‘Young Stars’ that generally has less than a few hundred Stars.
A supernova remnant is the structure that’s left after a star explodes in a supernova.
There are 3 types of supernova remnants: shell-like, composite and mixed-morphology (or thermal composite).
What is the Milky Way?
The Milky Way is a Spiral Galaxy, containing over 200 billion Stars, and actually forms part of the Constellation of Sagittarius. It is the Galaxy that contains the solar system and it gets its name from the fact that it looks like a hazy swirl or river of milk across the sky, when viewed from earth.
It is made up of gas, dust and stars, with spiral arms wrapped around it, and a massive black hole in the center of the Galaxy.
Not all of the Stars in the Universe are contained within the Milky Way. The Stars that make up the Constellation of Microscopium are located quite far from the Milky Way.
It is at its brightest if looking towards the galactic center in the direction of Sagittarius.
The Stars that make up the Milky Way are many light years away and cannot be individually identified by the naked eye.
Background & Facts:
The Greeks were the first ancient culture to name Constellations in the sky.
It was the Greek Astronomer – Ptolemy, who first cataloged the 48 early constellations, in the 2nd Century (2 AD.) andlisted them in his Almagest (a book recording astronomical data).
Microscopium is not one of the 48 Ptolemy catalogued Constellations but it is one of the 88 modern Constellations defined by the IAU.
In 1603, The German Astronomer – Johann Bayer, systematically assigned names to the brightest stars and cataloged them in his Star atlas – ‘Uranometria Omnium Asterismorum’
The Bayer designations are stellar designations where the stars within Constellations are initially identified by a name or a letter from the Greek Alphabet from Alpha through Omega (in order of brightness).
1. The names of the Stars in a Constellation usually begin with a letter of the Greek alphabet, usually starting with– Alpha, then beta, gamma etc.
Although in Microscopium, the first Star is designated the Gamma Star.
2. Followed by the genitive form of their parent constellation’s Latin name – ‘Microscopi ‘with ‘i’, makes the genitive name ‘Microscopii’.
3. Giving the first Star in Microscopium the name ‘Gamma Microscopii’.
The mainstars of Microscopium are named by their apparent magnitude (luminosity) from the brightest to faintest star in decreasing order:
1. Gamma Microscopii (y Mic) – an apparent visual magnitude of 4.68
2. Epsilon Microscopii (e Mic) – a variable visual magnitude of 4.72
3. Theta 1 Microscopii (θ Mic) – an apparent visual magnitude of 4.81
4. Alpha Microscopii (a Mic)– an apparent visual magnitude of 4.88
5. Iota Microscopii (i Mic)- an apparent visual magnitude of 5.11
6. Nu Microscopii (v Mic)– an apparent visual magnitude of 5.12
7. 2 Piscis Austrini (HR 8076)- an apparent visual magnitude of 5.20
8. HD 201772- an apparent visual magnitude of 5.25
9. Zeta Microscopii (z Mic)- an apparent visual magnitude of 5.31
10. HD 198716 – an apparent visual magnitude of 5.34
The importance of the Constellations dates way back to the times of the Babylonians who identified constellations with bright Stars.
One of the first records of the Stars is from Mesopotamia. as recorded in the Babylonian astrological catalogue.
The image the identified for Microscopium was that of a type of microscope of perhaps the top of a microscope like the classic compound microscope.
How do the Bright Stars of Microscopium shape up?
The Bright Stars
If you look up and into the night sky you can imagine the recognizable outline of the Constellation of Microscopium, which is a microscope.
This main constellation is made up of 5 main Stars
Stars with Planets
Microscopium has 2 Stars with an exoplanets orbiting around it in the solar system but it is unlikely to be able to support life forms.
- WASP-7 F-type Star
- HD 205739 – a Yellow White Dwarf Star
The furthest exoplanet discovered was actually in the Andromeda Galaxy, not in the Milky Way.
Not all the stars within the Microscopium Constellation are visible to the naked eye but with telescopes and modern imagery techniques is it possible to glimpse all of the stars.
FACT: An exoplanet (also referred to as an extrasolar Planet) is a planet that orbits a Star that is not located within our Solar System (exoplanets do not orbit our Sun)
Nothing stands still in the sky.
Planets are continually being discovered and lists updated.
The Constellations change their positions throughout the year as the Earth rotates around the Sun.
This means our position in space is forever changing and as a result our view of what’s in space changes too, and will continue to do so.
What is the purpose of Microscopium?
In ancient times the dots, bright lights and perceived objects in the sky were of great interest and the makings of folklore to a great range of people from seamen to farmers.
From children to the elderly, we have had an ongoing fascination, with our solar system and star system. Perhaps it’s because the enormity and variety within it makes us realize just how large and exciting the universe is.
FACT: The Star System or Stellar System is a small number of stars that orbit around each other and are bound together by gravity.
When it becomes a large group of stars, again bound together in the same way, by gravity, it is known as a Galaxy or Star Cluster.
Whether they contain small groups of stars or larger groups of start the both come under the classification of ‘Star System’.
The Microscopium celestial pole
The celestial pole defines the poles of the celestial equatorial coordinate system.
An object at the Celestial pole has a declination of 0 degrees.
- The declinations for the north celestial pole is +90 degrees
- The declinations for the south celestial pole is -90 degrees
The celestial poles are not permanently in a fixed position against the background of the stars as everything moves in Space.
Microscopium is located in the southern celestial sky at a +45 degree north and -90 degrees south declination, and an average 21 hours right ascension.
Navigational tools in the sky
The many Constellations in the night sky were a useful navigation tool and guide as well as the subject of legends and myths.
42 of the Constellations have been named after animals with a story behind each name.
Historical significance: Constellation of Microscopium
When it comes to the many recognized constellations in the sky, Microscopium is one of the smaller Constellations, ranking the 66th largest in the sky.
However the origins of the earliest Constellations probably date back to prehistory.
Many ancient civilizations have related the Constellations in the sky to suit their beliefs and creations itself. They have been the subject of folklore and experiences for a very long time.
There are no known myths and legends surrounding the origin and names of the Microscopium Constellation.
Ancient associations with the constellations
The Greeks, the Romans and the Sumerians all had an interest in the constellations in the sky.
The Sumerians were the first literate civilization of the Ancient Mesopotamia (an area occupying parts of Turkey and the Syria of today, Iraq, Iran). The Sumerian civilization was not unified like the ancient Greek or Roman civilizations it was bonded by a common attitude.
Their belief systems featured many deities. They regarded their gods as being responsible for everything and as such held them in great respect. Many stories arose as a result.
For thousands of years, various cultures around the world have identified and named the constellation we know and see in the night sky as Microscopium.
The Mesopotamian civilization (the first known civilization) identified constellations like Auriga. They used the orientation of the constellations to set the seasons for sowing crops and harvesting.
FACT: The ancient lands of the Mesopotamians now stretches across Turkey, Syria, Iraq and Kuwait
Microscopium and the other constellations in the sky had a practical use.
The Babylonians also recorded details of various bright stars within the constellations in their Babylonian star catalogues before 100BCE.
What is the difference between a constellation and an asterism?
An asterism is a group of stars that appear to form a pattern in the night sky but with no officially determined boundaries.
It can make up part of a constellation or cross the boundaries of an official constellation or even a defunct constellation.
An asterism is a more vague assembly of stars than a recognized constellation.
The meteor showers of Microscopium
There is only 1 minor annual meteor shower associated with the Constellation of Microscopium, the ‘Microscopids.
It is visible in the Southern Hemisphere late at night
‘The meteor shower associated with Microscopium, known as the Microscopids and is most active from June until mid-July each year with peak visibility usually between August 9-14.
Fun Facts about Constellations – Did you know that?
- The Constellation of Microscopium is not one of the 12 constellations of the Zodiac.
- Microscopium is represented in many cultures as a sign for harvest time and as a navigational guide.
- Microscopium is sometimes referred to as a polygon with 4 segments
- There are over 4000 known exoplanets in the night sky, with another 5000 awaiting classification
- The scale of a Constellation is measured in square degrees
- The planet Jupiter is often cited when making size comparisons between planets or stars. The Jupiter mass is a unit of mass equal to the total mass of planet Jupiter
- The Constellation of Microscopium is the 66th largest and occupies around 0.5% of the night sky
- Charles Messier the French Astronomer who cataloged the Messier objects has a crater on the Moon named after him.
- Constellations like Microscopium are not part of our Solar System; they are groups of stars that appear to form shapes that are visible with the naked eye from Earth.
- The largest Constellation is called Hydra and the smallest Constellation is called Crux
- The Sun does not belong to any constellation.
- A Constellation does not actually exist as a fixed object, it is a group of bright stars that happen to be in a random place and are light years apart and ever moving. We see the pattern of their presence.
- The center of a Galaxy does not contain a Giant Star it contains a massive Black Hole.
- Red Dwarf is not a Dwarf Planet it is a Star. Most common Stars are Red Dwarf (cool Stars).
- Spiral Galaxies make up about two third of all the Galaxies in the Universe
Commonly Asked Questions
Q. What is the celestial sphere?
A. In astronomy and navigation terms, the celestial sphere is imaginary.
This virtual sphere has a large radius that is concentric with Earth.
We can imagine all objects in the night sky as being projected upon the inside of this celestial sphere, as if it has images placed inside a dome.
Q. What’s the difference between a Constellation and an asterism?
A. The stars that make up a Constellation have a definite position and form, whereas an asterism is a collection of stars without a fixed position
Q. What prevents us seeing the Stars and Constellations in the night sky?
A. Light pollution, fog, city lights and artificial lights all limit our visibility of the objects in the sky at night.
Q. Will the Constellations change over time?
A. The Constellations are continually on the move.
The images we form in our imagination to make objects, shapes and patterns out of the constellations have already shifted over time.
As we view the night skies from Earth they are likely to continue to shift and possibly in time the images may look very different.