4 Cassiopeiae
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| Deepsky Atlas | Links | Constellations: Cassiopeia -- Mother of Andromeda |
Major stars: alpha Cassiopeiae: Schedar: magn. 2,5: RA: 00h 40m 30.45s: Dec: +56° 32' 14.5' beta Cassiopeiae: Caph: magn. 2,4: RA: 00h 09m 10.57s: Dec: +59° 08' 59.4'. 4 Cassiopeiae is a giant star that can be located in the constellation of Cassiopeia. The description is based on the spectral class. 4 Cassiopeiae is not part of the constellation outline but is within the borders of the constellation. Based on the spectral type (M1III) of the star, the star's colour is red.
Myth
Cassiopeia belongs to a grouping that includes Cepheus, Andromeda, Perseus, and Cetus. For the story behind this grouping, click here.Maps
Each map can be clicked on to produce a 909x1199 version of it. They sport red labels, which look good on screen, but which disappear when used with red flashlights. Each map, therefore has a second link to a map better suited for printing in a graphics program, and using in the field. While they are quite large, they are all about 50k, and so are easy to view at today's modem speeds. The first map is a wide area view of the constellation, suitable for naked eye browsing. The next views are binocular width, showing stars to mag. 10, and labeling deepsky objects to magnitude 12.Interactive, wide area map of Cassiopeia
Click the map for a 909x1199 version of the above. Click here for a map better suited for use in the field.
Eastern Section
Click here for a map better suited for use in the field.
Western Section
Click here for a map better suited for use in the field.
Images
89k JPEG Stock 12 is a loose open cluster located in the far SW of the constellation. Its size is listed as 20', and it contains stars mag 8 and fainter. You find it on the bottom end (south) of the image, 2/3 to the left (east). Frankly, it's boring. The good stuff is a splash of muticolored stars 30' to the NW. From the Digital Sky Survey.
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Image on the left from the Digital Sky Survey. Color image on the right by Beat Kohler and posted on Astro Info, a service of the Swiss Astronomical Society. A multilingual web site, most of the information is available only in German.
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32k JPEG M52 (NGC7654) is a large (13'), condensed, rich open cluster on the western border of Cassiopeia. Total brightness is mag. 6.9. Stars range from mags. 9-13. Messier thought he saw nebulosity, but there is none. Image taken with a HISYS 22 on a 4' Meade at f6.3.
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24k JPEG NGC147 (Caldwell 17) is a very faint (mag. 9.3), very large (13'x8'), irregular shaped dwarf elliptical galaxy with a bright core accented by foreground stars at the core. It is located 5.4° south of Zeta Cassiopeiae. From the Digital Sky Survey.
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11k JPEG NGC185 (Best 12, Caldwell 18) is a pretty bright (mag. 9.2), very large (14'x12'), irregular shaped dwarf elliptical galaxy with a less pronounced core than its companion NGC147. Dreyer says it is 'resolvable,' meaning there are dark markings in the middle. It is located 5.4° south of zeta Cassiopeiae. From the Digital Sky Survey.
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64k JPEG NGC281 (Best 13) is an open cluster with nebulosity located 1.7° east of Shedar (Alpha Cassiopeiae). Dreyer's description reads as follows: Faint (mag. 7), very large (35'), diffused, with a small triple star on the northwest edge. The nebulosity, sometimes called the Pacman Nebula, responds to filters, and even better to photography. It lies in a rich field. Image by Marco Lorenzi taken on film through an 8', f4, coma corrected Newtonian.
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4 Cassiopeiae 4
47k JPEG Object 4 (Be4) in the Berkeley University Catalog of open clusters. This is a mag 10.6 grouping with members at mags 12.5 and fainter. Size is about 5'. A notable feature is the tight, arrow shaped cluster pointing south, and an arc of stars to the ESE. Located 2° NE of Kappa Cassiopeiae. From the Digital Sky Survey.
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71k JPEG IC59 and IC63 are parts of a reflection nebula located .5° north and north-east of Navi (Gamma Cassiopeiae. Both are fairly faint and extremely large. Dreyer's little 'remarkable' code sits after the size description, rather unusual. The photograph from the Digital Sky Survey suggests you may have better luck with IC63. The plates are somewhat blue sensitive, though. Also, while you fit everything in a 1° field, you will do better keeping Navi out of the field.
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6k GIF NGC457 (Best 14, Caldwell 13) is a bright (mag. 6.4), large (13'), pretty rich cluster with stars from mag. 8 and fainter. Called the Owl Cluster, it is located 2.1° SSW of Ruchbah (Delta Cassiopeiae). The image is a drawing by Peter Schlatter of observations through a 10' Schmidt-Cassegrain telescope at 62x on August 31, 1995.
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34k JPEG NGC559 (Caldwell 8) is an open cluster located 2.8° west of Epsilon Cassiopeiae. Dreyer calls it bright (mag. 9.5), pretty large (4'), and pretty rich. It contains about 60 stars, mag. 10.6 and fainter. From the Digital Sky Survey.
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32k JPEG M103 (NGC581) is a pretty large (6'), round, rich open cluster 1° NW of Delta Cassiopeiae. Total brightness is mag. 7.4. Stars range from mags. 10-11. Image taken with a HISYS 22 (two minute exposure) on a 4' Meade at f6.3.
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65k JPEG NGC663 (Best 15, Caldwell 10) is another open cluster located 2.4° SSW of Epsilon Cassiopeiae. Dreyer calls it bright (mag. 7.1), large (16'), and extremely rich. It contains about 80 stars, mag. 8.4 and fainter. Several of the brighter stars make pretty pairs. From the Digital Sky Survey.
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79k JPEG Collinder 463 is a pretty open cluster, nice in moderately sized scopes, gorgeous in 16' and larger. Located in the far north of the constellation, its overall magnitude is 5.7, with individual stars at 8.5 and fainter. About 40 stars in a 36' field. From the Digital Sky Survey.
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23k JPEG NGC743 is another open cluster located 4.2° east of Ruchbah (Delta Cassiopeiae). It's not rich and has a double star involved. It contains about 12 stars, mag. 10 and fainter. Shaped like 'an arrowhead with a jewel inside it.' From the Digital Sky Survey.
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23k JPEG Stock 2 is an open cluster located 2° NNW of the Double Cluster in Perseus. This is a large cluster, one degree across, containing 50 stars, mag. 8.2 and fainter. A very nice binocular object. From the Digital Sky Survey.
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Constellation
RA / DEC
Magnitude A / B / C
Separation A-BC/ AC
Position angle A-BC / AC
Spectral class A / B / C
Colour A / B / C
RA / DEC
Magnitude A / B / C
Separation A-BC/ AC
Position angle A-BC / AC
Spectral class A / B / C
Colour A / B / C
: Cassiopeia
: 00:49:05 / +57.48
: 3.5 / 7.4
: 13”
: 319°
: G0V dM0
: Yellow / Orange-red
: 00:49:05 / +57.48
: 3.5 / 7.4
: 13”
: 319°
: G0V dM0
: Yellow / Orange-red
Date / Time
Observing Location
Seeing / Transparency
Telescope
Eye-piece
Magnification / Field of View '
Observing Location
Seeing / Transparency
Telescope
Eye-piece
Magnification / Field of View '
: 19/08/09 / 01:00
: Landgraaf
: 3 / 5
: Orion Optics UK 300 mm
: 12 mm Nagler type 4
: 133 / 37
: Landgraaf
: 3 / 5
: Orion Optics UK 300 mm
: 12 mm Nagler type 4
: 133 / 37
Eta Cassiopeiae is a strikingly colourful pair of stars. Eta's primary is bright yellow, while its dim companion looks deep orange with a hint of red. This attractive couple lies within an asterism that, using the right magnification, looks like a small dolphin (see my sketch for details). The dolphin asterism consists of 13 stars, oriented southwest northeast, with eta Cassiopeiae situated at the tip of the tail fin. Eta Cassiopeiae was allready easily split in the 22mm Nagler. After trying all possible magnifications, I liked the view of both the double and the asterism best using the 12mm Nagler T4, giving a magnification of 133x and a field of view of 37'.
The common name for Eta Cassiopeiae is Achird, a name with no real meaning. William Herschel probably first discovered this double star in August 1779. According to his notes in his journal for august 1779 he came across Eta Cassiopeiae while selecting double stars he wanted to use for determining the stellar parallax.
4 Cassiopeiae
In the left margin you see that Herschel examined alpha, beta, gamma, delta, epsilon and eta Cassiopeiae (the parts about eta are marked in a light green color). He writes about these 6 stars: alpha is double but too far asunder. beta, gamma, delta, epsilon are single. eta is double and will do. Source: The Herschel Archive
4 Cassiopeiae Lane
Both Eta Cassiopeiae A and B are situated at a distance of 19 light-years. It is a physical binary with a period of 480 years and the separation varies between 5' and 16'. At the moment Eta Cassiopeiae A and B are separated by 13' . As you can see on the image to the right, the position angle is 319 degrees. South is up, east is to the right, the same orientation as my sketch. (Source: Voyager by CarinaSoft)
Eta Cassiopeiae is a very interesting couple for visual observers, especially if you realise what you are actually looking at. The magnitude 3.5 A component is a star almost identical to our Sun, a G0 (yellow) main sequence dwarf star. Its radius is about 1.03 Suns, so its almost the same diameter as our Sun. The luminosity of eta Cassiopeiae A is 1.28 Suns. This star gives you an idea what our Sun would look like when placed at a distance of 19 light years. The magnitude 7.4 B component is a main sequence M0 Red dwarf. Because it is situated at the same distance as the A-component you can see how the brightness of stars drops dramatically as you go down to the cooler regions of the main sequence of the HR diagram.
On the 'home-made' HR diagram below you see the the relative positions of eta Cassiopeiae A (yellow dot) and eta Cassiopeia B (red dot) on the main sequence, based on data from Voyager by CarinaSoft (Absolute magnitude and Temperature).
Eta Cassiopeiae is a very interesting couple for visual observers, especially if you realise what you are actually looking at. The magnitude 3.5 A component is a star almost identical to our Sun, a G0 (yellow) main sequence dwarf star. Its radius is about 1.03 Suns, so its almost the same diameter as our Sun. The luminosity of eta Cassiopeiae A is 1.28 Suns. This star gives you an idea what our Sun would look like when placed at a distance of 19 light years. The magnitude 7.4 B component is a main sequence M0 Red dwarf. Because it is situated at the same distance as the A-component you can see how the brightness of stars drops dramatically as you go down to the cooler regions of the main sequence of the HR diagram.
On the 'home-made' HR diagram below you see the the relative positions of eta Cassiopeiae A (yellow dot) and eta Cassiopeia B (red dot) on the main sequence, based on data from Voyager by CarinaSoft (Absolute magnitude and Temperature).