Professor Mike Merrifleld has been out with his backyard telescope again - and has another Caldwell Object to tell us about. More links and info in full description ↓↓↓ IC 342 is known as The Hidden Galaxy and is the fifth object in the Caldwell Catalogue. More Caldwell objects: https://www.youtube.com/playlist?list=PLXJEVJey9Wz4RQK6uXH0O0t9504NnyzJL More videos with Mike Merrifield: https://www.youtube.com/playlist?list=PLcUY9vudNKBNGAgplgACrGL9UlxyDHq7k Messier Objects playlist: http://bit.ly/MessierObjects Back us on Patreon: https://www.patreon.com/deepskyvideos Astronomy at The University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Video by Brady Haran and James Hennessy More of Brady's latest work: https://www.bradyharanblog.com/

Dr Emma Chapman discusses Cloud-9 - a deep sky object that has all the ingredients of a galaxy except the stars. More links and info in full description ↓↓↓ The First RELHIC? Cloud-9 is a Starless Gas Cloud (paper): https://iopscience.iop.org/article/10.3847/2041-8213/ae1584 Emma Chapman is based a the University of Nottingham. More about her and her latest book here: https://linktr.ee/RadioUniverseBook Messier Objects playlist: http://bit.ly/MessierObjects Back us on Patreon: https://www.patreon.com/deepskyvideos Astronomy at The University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Video by Brady Haran Latest from Brady across his projects: https://www.bradyharanblog.com/

Professor Mike Merrifield is back in the Caldwell Catalogue and this time we unexpectedly discuss why the sky is blue... More links and info in full description ↓↓↓ The Iris Nebula is also known as NGC 7023 and Caldwell 4. Mike Merrifield is an emeritus professor from the University of Nottingham. Caldwell Playlist: https://www.youtube.com/playlist?list=PLXJEVJey9Wz4RQK6uXH0O0t9504NnyzJL Messier Objects playlist: http://bit.ly/MessierObjects Paper - The Excitation of Extended Red Emission: New Constraints on its Carrier From HST Observations of NGC 7023: https://arxiv.org/abs/astro-ph/0509352 Back us on Patreon: https://www.patreon.com/deepskyvideos Astronomy at The University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos Video by Brady Haran and James Hennessy

Professor Mike Merrifield discusses Caldwell 3 (aka NGC 4236) - leading to talk about the tip of the Red Giant Branch and so-called Helium Flashes. More links and info in full description ↓↓↓ Mike Merrifield is an emeritus professor from the University of Nottingham. The M81 group of galaxies: New distances, kinematics and structure - https://ui.adsabs.harvard.edu/abs/2002A%26A...383..125K/abstract More Caldwell Catalogue videos: https://www.youtube.com/playlist?list=PLXJEVJey9Wz4RQK6uXH0O0t9504NnyzJL Messier Objects playlist: http://bit.ly/MessierObjects Back us on Patreon: https://www.patreon.com/deepskyvideos Astronomy at The University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos Video by Brady Haran

Full interview with SETI's Seth Shostak from our video about NGC 2403 - Main video is at -- https://youtu.be/kkNWEu5KWkY -- More links and info in full description ↓↓↓ Seth Shostak: http://sethshostak.com Seth Shostak's thesis: https://core.ac.uk/download/pdf/11812191.pdf Messier Objects playlist: http://bit.ly/MessierObjects Back us on Patreon: https://www.patreon.com/deepskyvideos Astronomy at The University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos Video by Brady Haran

Mike Merrifield and Seth Shostak discuss a bewildering discovery in NGC 2403... and an offer to its alien inhabitants -- Patreon bonus: https://www.patreon.com/posts/129506586 -- Full Shostak video: https://youtu.be/xy2mE07Pp8E NGC 2403 is also known at Caldwell 7 Our video on Caldwell 1 - https://youtu.be/Et2Ij161PXE Our video on Caldwell 2 - https://youtu.be/Or3Db6ENf84 Messier 33 - https://youtu.be/4shqOBkCki8 Seth Shostak: http://sethshostak.com Seth Shostak's thesis: https://core.ac.uk/download/pdf/11812191.pdf Mike Merrifield is an emeritus professor from the University of Nottingham: https://about.me/michael.merrifield Messier Objects playlist: http://bit.ly/MessierObjects Back us on Patreon: https://www.patreon.com/deepskyvideos Astronomy at The University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos Video by Brady Haran and James Hennessy

Abell 1 is the first galaxy cluster in the so-called Abell Catalogue. Professor Meghan Gray has the story. More links and info in full description ↓↓↓ Professor Gray is based at the University of Nottingham - https://www.nottingham.ac.uk/physics/people/meghan.gray More videos with Dr Gray - https://www.youtube.com/playlist?list=PLcUY9vudNKBORQN625NgO3c4T82M6w2st Messier Objects playlist: http://bit.ly/MessierObjects Back us on Patreon: https://www.patreon.com/deepskyvideos Astronomy at The University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos Video by Brady Haran and James Hennessy

Professor Mike Merrifield on the second entry in the so-called Caldwell Catalogue, a planetary nebula with a fascinating story to tell. More links and info in full description ↓↓↓ More Caldwell Catalogue videos: https://www.youtube.com/playlist?list=PLXJEVJey9Wz4RQK6uXH0O0t9504NnyzJL Mike Merrifield is an emeritus professor from the University of Nottingham. Messier Objects playlist: http://bit.ly/MessierObjects Back us on Patreon: https://www.patreon.com/deepskyvideos Astronomy at The University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos Video by Brady Haran

Professor Meghan Gray discusses the double star Albireo (also known as Beta Cygni) at the head of swan in the constellation Cygnus... More links and info in full description ↓↓↓ Messier Objects playlist: http://bit.ly/MessierObjects Telescopes playlist: https://www.youtube.com/playlist?list=PLFDDC58C2516AE284 Back us on Patreon: https://www.patreon.com/deepskyvideos More videos with Meghan Gray: https://www.youtube.com/playlist?list=PLcUY9vudNKBORQN625NgO3c4T82M6w2st Some papers from this video... Spectroscopic notes: https://adsabs.harvard.edu/full/1897ApJ.....6..322H A celestial matryoshka: dynamical and spectroscopic analysis of the Albireo system: https://ui.adsabs.harvard.edu/abs/2021MNRAS.502..328D/abstract Yet another star in the Albireo system: https://arxiv.org/abs/2203.04222 Gaia Shows That Messier 40 is Definitely Not a Binary Star: https://arxiv.org/abs/1612.00834 Astronomy at The University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos Video by Brady Haran

The open cluster NGC 188 has retained an unusual population of middle-aged stars due to an orbit which spends long periods away from the messy galactic plane. More links and info in full description ↓↓↓ Discussed by Professor Mike Merrifield, emeritus professor from the University of Nottingham. The cluster is also dubbed Caldwell 1, the first entry in Patrick Moore's so-called Caldwell Catalogue of objects worth observing. Paper: Accurate, Precise, and Physically Self-consistent Ages and Metallicities for 400,000 Solar Neighborhood Subgiant Branch Stars - https://arxiv.org/abs/2407.18307 More Caldwell Catalogue videos: https://www.youtube.com/playlist?list=PLXJEVJey9Wz4RQK6uXH0O0t9504NnyzJL Messier Objects playlist: http://bit.ly/MessierObjects Back us on Patreon: https://www.patreon.com/deepskyvideos Astronomy at The University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos Video by Brady Haran

Professor Meghan Gray discusses how a musical link started her exploration of this Near Earth Asteroid. More links and info in full description ↓↓↓ Composer Kaija Saariaho's page: https://saariaho.org/works/asteroid-4179-toutatis IAU's Minor Planet Centre: https://www.minorplanetcenter.net/db_search/show_object?object_id=4179 The Ginger-shaped Asteroid 4179 Toutatis: New Observations from a Successful Flyby of Chang'e-2: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3860288/ Our Messier Objects playlist: http://bit.ly/MessierObjects Prof Meghan Gray: https://www.nottingham.ac.uk/physics/people/meghan.gray More viedos with Dr Gray (mainly on our sister channel Sixty Symbols): https://www.youtube.com/playlist?list=PLcUY9vudNKBORQN625NgO3c4T82M6w2st Back us on Patreon: https://www.patreon.com/deepskyvideos Astronomy at The University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos Video by Brady Haran and James Hennessy

Professor Meghan Gray discusses the Great Comet of 1997, Hale-Bopp. Also known less grandiosely as C/1995 O1. More links and info in full description ↓↓↓ Circular about Hale-Bopp's discovery: http://www.cbat.eps.harvard.edu/iauc/06100/06187.html#Item1 JWST Observations of Comet C/1995 O1 (Hale-Bopp) at 46 au: https://ui.adsabs.harvard.edu/abs/2022DPS....5430902K/abstract Messier Objects playlist: http://bit.ly/MessierObjects Brady visits Messier's grave: https://youtu.be/W3-hwKQqy0I Back us on Patreon: https://www.patreon.com/deepskyvideos Astronomy at The University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos Video by Brady Haran

Professor Meghan Gray discusses the immense galaxy cluster El Gordo (The Fat One), also known less catchily as ACT-CL J0102-4915. More links and info in full description ↓↓↓ Professor Gray: https://www.nottingham.ac.uk/physics/people/meghan.gray The Atacama Cosmology Telescope: ACT-CL J0102-4915 "El Gordo," a Massive Merging Cluster at Redshift 0.87 - https://ui.adsabs.harvard.edu/abs/2012ApJ...748....7M/abstract JWST's PEARLS: A new lens model for ACT-CL J0102−4915, "El Gordo," and the first red supergiant star at cosmological distances discovered by JWST - https://ui.adsabs.harvard.edu/abs/2023A%26A...672A...3D/abstract Weighing "El Gordo" with a precision scale - https://iopscience.iop.org/article/10.1088/0004-637X/785/1/20 Head-to-Toe Measurement of El Gordo: Improved Analysis of the Galaxy Cluster ACT-CL J0102–4915 with New Wide-field Hubble Space Telescope Imaging Data - https://iopscience.iop.org/article/10.3847/1538-4357/ac294f Messier Objects playlist: http://bit.ly/MessierObjects PERIODICVIDEOS (chemistry videos): https://www.youtube.com/user/periodicvideos NUMBERPHILE (math videos) : https://www.youtube.com/user/numberphile Astronomy at the University of Nottingham: https://www.nottingham.ac.uk/astronomy/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos Back us on Patreon: https://www.patreon.com/deepskyvideos Video by Brady Haran and James Hennessy

Professor Meghan Gray explains the sometimes strange phenomenon of twin quasars. More links and info in full description ↓↓↓ Professor Gray is an astronomy professor at The University of Nottingham - https://www.nottingham.ac.uk/physics/people/meghan.gray A close quasar pair in a disk–disk galaxy merger at z = 2.17 - https://doi.org/10.1038/s41586-023-05766-6 0957+561 A, B: twin quasistellar objects or gravitational lens? - https://ui.adsabs.harvard.edu/abs/1979Natur.279..381W/abstract MULTIPLE-MIRROR TELESCOPE OBSERVATIONS OF THE TWIN QSOs 0957+561 A,B - https://articles.adsabs.harvard.edu/pdf/1979ApJ...233L..43W Messier Objects playlist: http://bit.ly/MessierObjects Deep Sky Videos website: http://www.deepskyvideos.com/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos More about the astronomers in our videos: http://www.deepskyvideos.com/pages/contributors.html Supported by the University of Nottingham https://www.nottingham.ac.uk/astronomy/ Back us on Patreon: https://www.patreon.com/deepskyvideos Video by Brady Haran and James Hennessy

An intergalactic stream of stars in the galaxy cluster Abell 1795 - featuring Professor Mike Merrifield. More links and info in full description ↓↓↓ Back us on Patreon: https://www.patreon.com/deepskyvideos MMTF-Hα and HST-FUV Imaging of the Filamentary Complex in ABELL 1795: https://ui.adsabs.harvard.edu/abs/2009ApJ...703L.172M/abstract Michael Merrifield: https://www.nottingham.ac.uk/physics/people/michael.merrifield Messier Objects playlist: http://bit.ly/MessierObjects Deep Sky Videos website: http://www.deepskyvideos.com/ Twitter: https://twitter.com/DeepSkyVideos Facebook: http://www.facebook.com/DeepSkyVideos More about the astronomers in our videos: http://www.deepskyvideos.com/pages/contributors.html Supported by the University of Nottingham https://www.nottingham.ac.uk/astronomy/ Video by Brady Haran and James Hennessy