NGC7635 (Caldwell 11) is the Bubble Nebula, a small (15'x8'), dim bit of nebulosity several minutes across. Here are wide angle and narrow angle views. A mag. 8 star shines in the middle of it.
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| NGC7789 (Best 16) is an open cluster that improves with aperture. Shining at mag. 6.7, Dreyer describes it as very large (16'), very rich, very much condensed, with stars mags. 11-18. Opinions vary as to whether 300 or 1000 stars reside here. Easy to find, this cluster sits mid-way between Sigma and Rho Cassiopeiae. 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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Called 'anon' by Jeff Bondono, this is not an object as such, but an interesting star field of doubled stars. Included are both the Digital Sky Survey image, and a detailed map from The Sky for Windows, the latter showing the spectral colors of the brighter stars. It is 1.2° SSW of Caph (Beta Cassiopeiae).
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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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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.
| Map | Printable Map | 242k JPEG |
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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.
| Map | Printable Map | More info. |
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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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4 Cassiopeiae X 2
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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4 Cassiopeiae Lane
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Keen Northern Hemisphere stargazers will rejoice that the winter solstice, which occurs on 22 December 2019, brings the longest nights of the year. This is the time when observers in the UK have twelve hours of darkness to enjoy – moonlight notwithstanding – starting at 6pm GMT. If you relish an early evening stargaze before it gets too cold, one readily identifiable constellation that lies virtually overhead at 7pm GMT as seen from the British Isles during the festive season is Cassiopeia (pronounced kas-ee-uh-pee-uh).
Most people learn to identify Cassiopeia as a five-star M-shaped (if you are facing north at this time of year) pattern of second- and third-magnitude stars that can easily be encompassed by the span of an outstretched hand at arm's length. If you are lucky enough to receive a new telescope for Christmas, why not seek out some of the constellation's beautiful double and multiple stars set against the rich backdrop of the Milky Way.
Sigma (σ) Cassiopeiae
α = 23h 59.0m, δ = +55° 45' (J2000.0)
Magnitudes: +5.0 & +7.1
Separation: 3.1 arcseconds
Sigma (σ) Cassiopeiae is a close double star for 10-cm (4-inch) aperture telescopes and larger. A night of steady seeing and a magnification of around 150× is required to see this pairing of a magnitude +5.0 primary and magnitude +7.1 companion separated by 3.1 arcseconds. Look for bluish-white and yellow tints. Sigma Cassiopeiae is about 1,500 light-years distant. And here's another fact: owing to precession, Sigma Cassiopeiae has a mean right ascension of exactly (give or take a second) of 00h 00m 00s at the current J2019.9 epoch!
Eta (η) Cassiopeiae, aka ‘Achird‘
α = 00h 49.1m, δ = +57° 49' (J2000.0)
Magnitudes: +3.4 & +7.5
Separation: 13.4 arcseconds
Commonly known as Achird, Eta (η) Cassiopeiae is a fine double star with noticeable colours first recognised as a binary system by William Herschel in the summer of 1779. An easy pair for small telescopes at 50× owing to the wide 13.4 arcsecond separation, its magnitude +3.4 primary is yellow, while the magnitude +7.5 companion is orange. The orbital period of Eta Cassiopeiae is about 500 years and its distance from Earth is 19.4 light-years.
4 Cassiopeiae Tires
Σ 163 (Cassiopeia)
α = 01h 51.3m, δ = +64° 51' (J2000.0)
Magnitudes: +6.8 & +8.8
Separation: 34.8 arcseconds
4 Cassiopeiae 4
Although the accompanying illustration shows a high-power view, a colourful double in Cassiopeia that doesn't require large magnifications to resolve is Struve 163 – frequently appreviated to Σ 163 in catalogues – on account of its wide, 34.8 arcsecond separation. A small telescope at 30 to 50× magnification is all that's required to view the magnitude +6.8 orange primary and its magnitude +8.8 bluish companion. The stars lie about 2600 light-years from the Sun.
Iota (ι) Cassiopeiae
α = 02h 29.1m, δ = +67° 24' (J2000.0)
Magnitudes: +4.6, +6.9 & +8.4
Separation: 2.6 & 7.6 arcseconds Casio 150 piano.
4 Cassiopeiae Words
We shall conclude this very brief tour of the best double and multiple stars Cassiopeia has to offer with what I consider to be the finest triple star in the entire sky. Iota (ι) Cassiopeiae is also a multiple star whose components typify the subtle and subjective nature of star colours. Whereas many perceive just three white stars, a large proportion of observers see a pure white primary, the closer companion as yellow-orange and the wider companion as bluish-white. Your perception of star colours can also vary with the type of telescope and eyepiece used. What do you see? However you interpret its component hues, you will need a night of good seeing and typically a 10-cm (4-inch) aperture ‘scope at around 150×, or more. Iota Cassiopeiae lies about 133 light-years distant.
Cassiopeia in fact and myth
Cassiopeia is an ancient constellation, one of the original 48 listed by Greek astronomer and mathematician Ptolemy (circa 100-170 AD). At the temperate northern latitudes of the British Isles, it's circumpolar – permanently above the horizon, never rising or setting. By size, Cassiopeia is the 25th largest out of the 88 constellations recognised today.
In Greek mythology, Cassiopeia is queen to King Cepheus and mother of Andromeda. Cassiopeia angered the sea god Poseidon by boasting that Andromeda was more beautiful than sea nymphs known as the Nereids. As punishment, Poseidon decreed that Andromeda should be sacrificed to the sea monster Cetus (but she was rescued by Perseus), while Cassiopeia was condemned to eternally revolve around the north celestial pole seated on her throne.
