Ten real historic instruments for observing, calculating and demonstrating the sky. The order is editorial, not a ranking of importance. Photograph credits: 1. Armillary sphere; Photograph by Mike Peel (www.mikepeel.net).; CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0; https://commons.wikimedia.org/wiki/File:Armillary_sphere,_Museum_Boerhaave_Leiden.jpg; 2. Astrolabe; Andrew Dunn; CC BY-SA 2.0; https://creativecommons.org/licenses/by-sa/2.0; https://commons.wikimedia.org/wiki/File:Astrolabe-Persian-18C.jpg; 3. Quadrant; Photograph by Mike Peel (www.mikepeel.net).; CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0; https://commons.wikimedia.org/wiki/File:Astronomical_quadrant,_Museum_Boerhaave_Leiden.jpg; 4. Sextant; ; Public domain; ; https://commons.wikimedia.org/wiki/File:Sextant.jpg; 5. Octant; Daderot; Public domain; ; https://commons.wikimedia.org/wiki/File:Royal_presentation_octant,_made_by_Jean_Baptiste_Magnie,_dedicated_to_King_Louis_XVI,_c._1786,_brass,_mahogany,_glass_-_Peabody_Essex_Museum_-_DSC06648.jpg; 6. Celestial globe; Rama; CC BY-SA 3.0 fr; https://creativecommons.org/licenses/by-sa/3.0/fr/deed.en; https://commons.wikimedia.org/wiki/File:Celestial_globe-CnAM_7432-IMG_6831.JPG; 7. Galilean telescope; Sailko; CC BY-SA 3.0; https://creativecommons.org/licenses/by-sa/3.0; https://commons.wikimedia.org/wiki/File:Galileo_galilei,_telescopi_del_1609-10_ca..JPG; 8. Orrery; Rama; CC BY-SA 3.0 fr; https://creativecommons.org/licenses/by-sa/3.0/fr/deed.en; https://commons.wikimedia.org/wiki/File:Orrery-MnM_15_NA_13-IMG_6003-black.jpg; 9. Meridian circle; Ranoutofusername; CC BY 4.0; https://creativecommons.org/licenses/by/4.0; https://commons.wikimedia.org/wiki/File:Círculo_meridiano_(Repsold_&_Söhne,_1889)._Museo_del_Observatorio_Astronómico_de_Quito.jpg; 10. Sundial; TwoWings; Public domain; ; https://commons.wikimedia.org/wiki/File:1913_sundial.jpg;