10,000 Galaxies Database                 The current estimate for the number of galaxies in the observable universe is 125 billion. The first decision was to decide a suitable number of galaxies to use in order to produce a manageable database. There are 6,060 galaxies from the NGC database which are included in Stellarium. So these were used to form the initial base. From here, 10,000 seemed like a tidy total and consequently the aim was to use galaxies listed in other catalogues to achieve this amount. The other catalogues used included: The Arp Catalogue A catalogue of peculiar galaxies produced by Halton Arp. The ESO Catalogue Hickson Compact Groups HCG Catalogue As defined by Paul Hickson (1982), “a compact group is a small, relatively isolated system of typically four or five galaxies in close proximity to one another.” The Index Catalogue IC The Principal Galaxies Catalogue PGC The VV Catalogue A catalogue of galaxies produced by Vorontsov and Velyaminov. The Uppsala General Catalogue UGC Seven main galaxy classes are included in the database.   1. Galaxy (plain!)   2. Active Galaxy   3. Interacting Galaxy   4. Radio Galaxy   5. Dwarf Galaxy   6. Blazar   7. BL Lacertae Object                     Galaxy Type                 There are 510 different descriptions used by Stellarium to specify the type of galaxy for the galaxies which have been selected for the database. The main 41 galaxy type descriptions are listed in the file “Top Types” and these descriptions are listed in order of frequency in the file “Top Types Ordered 2021”. Click on the icons to view the files.          Top Types 2021           Top Types Ordered 2021  Distribution of the 10,000 Galaxies           Across the Constellations                 It is interesting to investigate the distribution of the 10,000 galaxies across the constellations. None of the galaxies lie within the constellations Sagitta, Scutum and Serpens (Cauda) nor within the constellations Norma, Crux and Musca in the southern skies. The following lists show the constellations which have the highest concentration of the selected galaxies.        Northern Skies    Southern Skies   1. Virgo 767 1. Centaurus 194   2. Ursa Major 618 2. Indus 161   3. Leo 570 3. Grus 150   4. Cetus 562 4. Phoenix 127   5. Bootes 459 5. Pavo 121   6. Pisces 398   7. Pegasus 393   8. Coma Berenices 382   9. Eridanus (Borealis) 344 10. Draco 327 11. Hercules 325 12. Canes Venatici 309 13. Hydra 281 14. Andromeda 205 It is worth pointing out that there are146 selected galaxies within the constellation Serpens (Caput), as opposed to none in Serpens (Cauda). Also, Scorpius has just three. For a full list of constellations and the number of galaxies within each class, see the file “Constellations 2021”. Click on the icon to view the file.     Constellations 2021              Constellation Maps   The following files show the number of galaxies chosen for the 10,000 Galaxies Database which are in each constellation on maps of the constellations.   Click on relevant icon to view the required file.                     Northern Skies                                           Southern Skies              Research Questions                Some intriguing questions arose during the production process of the 10,000 Galaxies Database. These have been summarized and included in the following file “Galaxy Questions”. Click on the icon to view the questions.                  Galaxy Questions