Pictures of open star clusters

By Lee Dyson

Published: Monday, 02 August 2021 at 12:00 am

An open star cluster is a young group of loosely bound stars that all formed from the same vast region of cosmic gas known as a giant molecular cloud.

Open clusters contain just hundreds or a few thousand stars gravitationally bound, but because they are loosely bound the stars spread out from one another over time. This is why they are known as ‘open’ star clusters.

This weakness in gravitational attraction between the stars in an open cluster is what makes gives them such irregular shapes.

Open star clusters are are also young, at just tens or hundreds of millions of years old.

"NGC
NGC 659 by Jaspal Chadha, London, UK. Equipment: Takahasi TOA – 130N, 690 CCD, Ioptron CEM60 (unguided)

Open clusters vs globular clusters

Open star clusters can be easily contrasted with globular clusters, because their properties are almost the mirror opposite of one another.

  • Open star clusters are loosely-packed, containing hundreds or thousands of stars
  • Globular clusters are densely packed, containing hundreds of thousands or even millions of stars.
  • Open star clusters form loose, irregular shapes
  • Globular clusters form dense, consistently round shapes
  • Open star clusters are tens or hundreds of millions of years old
  • Globular clusters are some of the oldest objects in the Universe: even as old as 12 billion years
"NGC663,
NGC663, NGC654 & NGC659 – Open Clusters by Bill McSorley, Leeds, UK. Equipment: SW 150P Newtonian, EQ5 GoTo Mount, QHY8L cooled ccd OSC.

There are thousands of open star clusters in the Milky Way, and they can be found in the disc of our Galaxy.

While the individual stars in an open cluster may last for billions of years, the cluster itself won’t last as long, because the lack of strong gravitational attraction causes them to disperse over time.

Open star clusters are extremely beautiful objects to observe and to photograph. Below is a selection of images of open clusters captured by BBC Sky at Night Magazine readers and astrophotographers.

For more info, read our guide to the best star clusters to observe with the naked eye, or our guide to deep-sky astrophotography.

And if you do manage to photograph an open star cluster, be sure to send us your images or share them with us via Facebook, Twitter and Instagram.

"NGC659/663/654
NGC659/663/654 Cassiopeia Open Cluster Triple by Mark Griffith, Swindon, Wiltshire, UK. Equipment: Skywatcher NEQ6 pro mount & Equinox 80mm refractor, Atik 383L+ camera, motorised filter wheel and Astronomik LRGB filters.
"Kite
Kite Cluster by Japsal Chadha, London, UK. Equipment: Altair Astro RC250 TT, QSI 690 CCD, Ioptron CEM60 unguided, LRGB Altair Astro Filters
"Kite
Kite Cluster by Japsal Chadha, London, UK. Equipment: Takahashi 130, Reducer, QSI 690CCD, IoptronCEM60 mount
"Messier
Messier 7 by Luis Fernando Parmegiani, São Paulo, Brazil. Equipment: GSO RC8″, NEQ6 Skywatcher, QHY9M, RGB filters
"M11
M11 by Ron Brecher, Ontario, Canada. Equipment: SBIG STL-11000M, Baader LRGB filters, 10″ f/6.8 ASA astrograph, MI-250 mount, STL-11000’s external guider, 500mm f.l. Lumicon guide scope, FocusMax, MaximDL.
"M29
M29 – Open Cluster in Cygnus by Bill McSorley, Leeds, UK. Equipment: SW 150P Newtonian Reflector, QHY8L OSC cooled ccd camera, EQ5 GoTo Mount.
"M29
M29 by Simon Fletcher, Birmingham, UK. Equipment: Moonraker Dark Matter ED80 mkI, NEQ6, PhD guided, EOS450 (un-modded), Skywatcher LP
"Open
Open Cluster M36 in the constellation Auriga by Ron Larter, Lowestoft, Suffolk, UK. Equipment: 5″ skywatcher refracter, Canon 450D at prime.
"M38
M38 Cluster by Jaspal Chadha, London, UK. Equipment: Takahashi 130, iOptron CEM60, QSI 690 CCD, LRGB.
"M38
M38 by Bradley Swift, Rochdale, UK. Equipment: Skywatcher 150p Newtonian reflector, HEQ5 pro mount – unguided, Canon 1100D.
"NGC
NGC 2438 in the Middle of M46 by Kfir Simon, Namibia. Equipment: 16″ Dream Scope, 12″ F7.5 LX200, Ha, LRGB.
"Messier
Messier 46 – a Widefield Image by Kfir Simon, Namibia. Equipment: 16″ Dream Scope, 12″ F7.5 LX200, Ha, LRGB.
"M46
M46 and NGC 2438 by Dan Crowson, Animas, New Mexico, USA. Equipment: SBIG STF-8300M, Astro-Tech AT12RCT.
"M47
M47 by Dan Crowson, Animas, New Mexico, USA. Equipment: SBIG STF-8300M, Astro-Tech AT12RCT.
"M52
M52 by J Robertson by London, UK. Equipment: Celestron Edge HD8, Sony Alpha a3000.
"Messier
Messier 67 by Stephen Dean, East Cowes, Isle of Wight, UK. Equipment: Skywatcher 80mm ED, Canon EOS 1100D, Astronomik CLS filter, EQ5 mount, QHY 5 guide, PhD
"M67
M67 – Open Cluster in Cancer by Bill McSorley, Leeds, UK. Equipment: SW 150P Newtonian, EQ5 GoTo Mount, QHY8L cooled CCD.
"M67
M67 – Open Cluster in Cancer by Bill McSorley, Leeds, UK. Equipment: SW 150P Newtonian, EQ5 GoTo Mount, QHY8L OSC cooled CCD.
"M93
M93 – LRGB by Dan Crowson, Animas, New Mexico, USA. Equipment: SBIG ST-8300M, Astro-Tech AT90EDT
"M103
M103 – Open Cluster in Cassiopeia by Bill McSorley, Leeds, UK. Equipment: SW 150P Newtonian, EQ5 GoTo Mount, QHY8L OSC cooled CCD.
"M103
M103 Open Cluster by Mark Griffith, Swindon, Wiltshire, UK. Equipment: GSO 8″ Richey-Chretien Optical tube, Skywatcher NEQ6 pro mount, Atik 383L+ camera, motorised filter wheel and Astronomik LRGB filters.
"Messier
Messier 103 by Craig Dawes, Staffordshire, UK. Equipment: SW HEQ5 pro, SW ST80, QHY5, SW 100ED DS Pro, Canon 50D (Modded)
"IC
IC 4665 – Open Cluster by Bob Franke, Chino Valley, AZ, USA. Equipment: Takahashi FSQ-106ED, SBIG STF-8300M, Baader RGB filters, Losmandy G11 mount
"Melotte
Melotte 20 by Philip Pugh, Chippenham, Wiltshire, UK. Equipment: Konica Minolta Dynax 5D, Skywatcher Startravel 80, EQ1 mount, Tripod.
"Hyades
Hyades by Philip Pugh, Chippenham, UK. Equipment: Konica Minolta Dynax 5D, tripod.
"NGC206
NGC206 Open Cluster Andromeda Galaxy by Mark Griffith, Swindon, Wiltshire, UK. Equipment: GSO 8″ Richey-Chretien Optical tube, Skywatcher NEQ6 pro mount, Atik 383L+ camera, motorised filter wheel and Astronomik LRGB filters.
"Sail
Sail Boat Cluster by Jaspal Chadha, UK. Equipment: Skywatcher Esprit 100ed, QSI 690 CCD, iOptron CEM60 mount
"NGC
NGC 488 by Jaspal Chadha, London, UK. Equipment: Takahashi 130, QSI 690, CEM60 Mount, Astrodon filter LRGB.
"NGC
NGC 1342 aka Little Scorpion Cluster by Jaspal Chadha, London, UK. Equipment: TAK 130, Ioptron CEM60 Mount, QSI 690 CCD.
"NGC
NGC 1502 by Jaspal Chadha, London, UK. Equipment: Altair Astro RC 250TT, QHY9s Mono CCD, Chroma LRGB, Iotpron CEM60 mount
"Battle
Battle of the Clusters by Jaspal Chadha, London, UK. Equipment: Sky watcher Espirt 100ED, QHY9M CCD , LRGB, Ioptron CEM60.
"NGC1647
NGC1647 – Open Cluster in Taurus by Bill McSorley, Leeds, UK. Equipment: SW 150P Newtonian, HEQ5Pro Mount, QHY8L cooled CCD.
"Open
Open Cluster and Nebula in the Constellation Auriga by Stephen D Pastor, Mayhill, NM, USA. Equipment: Takahashi CCA250 f/5 Astrograph,a QSI683wsg CCD, Astrodon Gen 2 filters, Paramount ME.
"NGC
NGC 2112 (LRGB) by Dan Crowson, Missouri, USA. Equipment: SBIG ST-8300M, Astro-Tech AT90EDT.
"NGC
NGC 2420 by Ron Brecher, Ontario, Canada. Equipment: SBIG STL-11000M camera, Baader RGB filters, 10″ f/6.8 ASA astrograph, Paramount MX, QHY5 CCD, 80mm f/6 guide scope, FocusMax, TheSkyX.
"NGC
NGC 2420 by Ron Brecher, Ontario, Canada. Equipment: SBIG STL-11000M camera, Baader RGB filters, 10″ f/6.8 ASA astrograph, Paramount MX, QHY5 CCD, 80mm f/6 guide scope, FocusMax, TheSkyX.
"NGC6604,
NGC6604, Open Cluster in Serpens by William McSorley, Leeds, UK. Equipment: SW 150P Reflector, EQ5 GoTo Mount, QHY8L cooled CCD, SW ST80, Philips SPC900 webcam.
"NGC
NGC 6604 by Bill McSorley, Leeds, UK. Equipment: SW 150P, EQ5 Mount, QHY8L OSC CCD.
"NGC
NGC 6791 by Dan Crowson, Animas, New Mexico, USA. Equipment: SBIG STF-8300M, Astro-Tech AT12RCT.
"NGC
NGC 6791 by Stathis Mexias, Athens, Greece. Equipment: FLT 98, QHY9M.
"NGC6883
NGC6883 & NGC6871 by Bill McSorley, Leeds, UK. Equipment: SkyWatcher 150P Newtonian, HEQ5 Pro Mount, QHY8L cooled CCD.
"NGC
NGC 6910 by Bill McSorley, Leeds, UK. Equipment: SW 150P, EQ5 Mount, QHY8L OSC CCD.
"NGC
NGC 7039 & NGC 7048 by Dan Crowson, Dardenne Prairie, Missouri, USA. Equipment: SBIG ST-8300M, Astro-Tech AT90DT
"NGC7062
NGC7062 – Open Cluster in Cygnus by Bill McSorley, Leeds, UK. Equipment: SW 150P Newtonian, EQ5 GoTo Mount, QHY8L OSC cooled CCD.
"NGC7062
NGC7062 – Open Cluster in Cygnus by Bill McSorley, Leeds, UK. Equipment: SW 150P Newtonian, EQ5 GoTo Mount, QHY8L OSC cooled CCD.
"NGC
NGC 7062 by Dan Crowson, Dardenne Prairie, Missouri, USA. Equipment: SBIG ST-8300M, Astro-Tech AT90DT.
"NGC7686
NGC7686 – Open Cluster in Andromeda by Bill McSorley, Leeds, UK. Equipment: SW 150P Newtonian Reflector, QHY8L OSC cooled CCD, EQ5 GoTo Mount
"Caldwell
Caldwell 100 by Nick De Villiers, Calitzdorp, South Africa. Equipment: Atik 460EX, 8″ RC, CGEM mount Ha, oiii, sii filters.
"King
King 5 by Dan Crowson, Animas, New Mexico, USA. Equipment: SBIG STF-8300M, Astro-Tech AT12RCT
"King
King 17 by Dan Crowson, Animas, New Mexico, USA. Equipment: SBIG STF-8300M, Astro-Tech AT12RCT
"M52,
M52, NGC7653 & NGC7538 by Bill McSorley, Leeds, UK. Equipment: SW150P, EQ5 Pro Mount, QHYl cooled ccd.
"Around
Around M11 by Konstantinos Christodoulopoulos, Parnonas Mountain, Greece. Equipment: Canon EOS 450D, Canon EF 200mm f/2.8L lens, Skywatcher HEQ5 Synscan pro, Vixen ED81S, DMK21AU04, PHD guiding
"NGC
NGC 6910 and Sadr by Bill McSorley, Leeds, UK. Equipment: SW150P, EQ5 Mount, QHY8L OSC camera.
"Palomar
Palomar 9 by Dan Crowson, Animas, New Mexico, USA. Equipment: SBIG STF-8300M, Astro-Tech AT12RCT