Cassiopeia (Pronounciation:Cas-see-o-pee-ah, Abbrev:Cas, Latin:Cassiopeiae) is a constellation, one of 88 constellations that the night sky is divided into. The sky is not divided up equally between the constellations. Cassiopeia takes up 598.407 sq. degrees of the night sky which equates to 1.45% of the night sky. Cassiopeia is the 25th largest in terms of size in the night sky.
The constellation name means Queen of Ethiopia . The constellation is one of the original constellations that was devised by the Ancient Greco-Egyptian astronomer Ptolemy who lived between 90 A.D. and 168 A.D.
There are 5 stars that make up the main constellation. The hipparcos satellite scanned and detailed 2324 stars. There are 93 stars that can be seen with the naked eye in the constellation on a very clear night sky.
Cassiopeia is not a member of the Zodiac group of twelve constellations that appear when the Sun sets. Cassiopeia is a northern hemispheric constellation which means it can't be seen easily or at all from the southern hemisphere.
There are 20 Extrasolar Planets (Exoplanets) in this constellation that are detailed on this site. There is a dedicated page for exoplanets in Cassiopeia. The current largest star so far identified in the constellation of Cassiopeia is PZ Cassiopeiae.
There are 2 deep space objects that were identified by Charles Messier in this constellation. There are 1 non-Messier deep space objects that are covered on this site and the list is below.
The image at the top right of this page was generated using Night Vision, a free to use and download application by Brian Simspon.
You can't just go to one location and arrive at the constellation because the constellation is made up of stars at different locations and different distances. The nearest main star in the constellation is at a distance of 54.74 light years and the furthest main star is a distance of 549.10 light years. The average distance to the main stars is 268.66 light years.
The caveat of these stars are that they are catalogued on this site. If you know of a star that is nearer or further then do let me know in the comments and I'll add it to the site. The stars mentioned are from the Hipparcos catalogue or have been added because of their special status.
The nearest star to Earth is Achird which is roughly about 19.42 Light Years from the Earth. The nearest star to the Earth with an exoplanet is HD 7924 which is about 54.83 Light Years.
The furthest star that is located in the constellation is HIP 12972 and it is 326163.3 light years away from the Sun. The furthest figure is derived from either the 1997 or 2007 Hipparcos star catalogue parallax figure and it has been known to produce distances that are wrong.
The brightest star in Cassiopeia is Schedar and is located about 46.61 light years from the Sun. The star has a apparent magnitude of 2.24 but an absolute magnitude of -1.98 when the star is viewed from a distance of 10 Parsecs or 32.6 Light Years. The star is recognised as being the brightest in the constellation as it has the Bayer status of Alpha.
The dimmest star that can be seen in Cassiopeia with the naked eye is 52 Cassiopeiae. The dim star has an apparent magnitude of 6. The dimmest star that a person is able to see with their naked eye is 6.0 magnitude based on the table in the reference. Ref: University of Michigan.
AR Cassiopeiae is a large multiple star system, whilst most multiple star systems are binaries such as Sirius also known as Alpha Canis Majoris, AR Cassiopeiae has seven stars in the system. There is only one other star that has that many stars and that is Jabbah in the constellation of Scorpius.
PZ Cassiopeiae is one of the largest stars so far discovered. If it was at the centre of our solar system, we would be inside the star. It is over 1,200 times the size of our Sun but it is not the largest. The largest star accolade goes to UY Scuti at over 1,800 times the radius.
V762 Cassiopeiae is the furthest star you can see with the naked eye. To see V762 Cassiopeiae you will need to be a very clear sky as it is on the borders of what is visible with the naked eye, apparent magnitude 6.5.
Cassiopeia is one of four constellations that can be seen all the year round in the Northern Hemisphere. There is no best or worst time for it. The only thing that could affect your viewing is light and exactly where you are in the Northern Hemisphere.
If you are as far down south as Sydney, you will not be able to see the constellation. If you go further north, say in Darwin, you will just be able to see the constellation in the northerly direction. The constellation can be seen at about nine o'clock by looking north.
Cassiopeia was the queen of Philistia, now assumed to be latter day Ethiopia. Cassiopeia was married to King Cepheus, also a constellation. Cassiopeia was known to be very vain. When her daughter Andromeda was of a mature age, she was tied to a large rock to be sacrificed. Help would come from Perseus who would kill Cetus using the severed head of Medusa, the half-woman / half-serpent with snakes for hair and who could turn anyone to stone by looking at them. The Legend is told in Clash of the Titans film and in the 2010 remake.
Cassiopeia was name of a character in the original Battlestar Galactica series. Cassiopeia was a socialite character who became the love interest of the original Starbuck. In the second half of the series, her character was fleshed out a bit more and she became a medical technician.
The Sun is not in a constellation but if we were on the planet orbiting Proxima Centauri then our Sun would be in Cassiopeia. Our Sun would be located to the south west of Segin, also known as Epsilon Cassiopeiae.
There are 17 Meteor Showers that occur during the year within this constellation based on information gathered from Adam Mickiewicz University (Poland). The list below are major ones and which I have a date period for.
|Name||Activity||Peak Activity||Closest Star|
|Beta Cassiopeids||3 Jul- 19 Aug||29-Jul||Caph|
The following list contains the stars that make up the constellation. For a larger list of stars in the entire constellation area, please visit the For a list of named stars, that is stars that don't start HD or HIP, please visit Cassiopeia Star List page.
|Name||Bayer||Distance (Lt.Yr.)||Right Ascension||Declination||Spectral Type||Colour|
|Schedar||Alpha Cassiopeiae||228.25||00h 40m 30.39||+56d 32` 14.7||K0II-IIIvar||Orange|
|Caph||Beta Cassiopeiae||54.74||00h 09m 10.09||+59d 09` 00.8||F2III-IV||Yellow/White|
|Cih||Gamma Cassiopeiae||549.10||00h 56m 42.50||+60d 43` 00.3||B0IV:evar||Blue/White|
|Ruchbah||Delta Cassiopeiae||99.41||01h 25m 48.60||+60d 14` 07.5||A5Vv SB||White|
|Segin||Epsilon Cassiopeiae||411.82||01h 54m 23.68||+63d 40` 12.5||B2pvar||Blue/White|
|Is a Zodiac Sign||No|
|Area||598.407 sq. deg.|
|Percentage of Night Sky||1.45%|
|Site Exoplanet Count||20|
|Meteor Shower Count||17|
|Nearest Star with Exoplanet(s)||HD 7924|
|Largest Star||PZ Cassiopeiae|
|Dimmest Star||52 Cassiopeiae|
|Furthest Star||HIP 12972|
|Bright Star Count||93|
|Hipparcos Star Count||2324|
|Main Star Count||5|
|Messier Deep Space Object Count||2|
|Bordering / Neighbouring / Surrounding Constellations||Cepheus|
*Note: The number of Non-Messier Deep Space Object Count relates to how many are covered on this site not how many there are.
|Bubble Nebula||Emission Nebula||7,100 - 11,000||+61 12 06||23 20 48m 3|
|Heart Nebula||Emission Nebula||7,500||61:26:36||02h 33h 22|
|Messier 103 (NGC581)||Open Star Cluster||10000||+60:42||01h 33m 2|
|Messier 52 (NGC7654)||Open Star Cluster||5000||+61:35||23h 42m 2|
|NGC 1027||Open Star Cluster||3,100||+61:38:00||02h 42h 43|
|NGC 147||Galaxy in a Group of Galaxies||+48 30 31.46||00 33 12m 120|
|NGC 7789||Open Star Cluster||7,600||56:42:30||23h 57h 24|
|Owl Cluster||Open Star Cluster||7,922||58:17:27||1h 19h 32|
|Pacman Nebula||Star-Forming Nebula||9,000||56:37:26.33||00 52 41m 74|
|SN 1181||Supernova Remnant||+64 49 42||02 05 37m 0|
|SN 1572||Supernova Remnant||+64 08 27||00 25 21m 5|
|SN 1572A||Supernova Remnant||+64 08 27||00 25 21m 5|
|Soul Nebula||Emission Nebula||7,500||60:24:36||2h 55h 24|
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