Uranus and its Moons
Like the other giant planets of the Solar System, also Uranus has a large court of satellites (27 are known today), of which the five imaged here (Miranda, Ariel, Umbriel, Titania and Oberon) are the brightest.
These moons are however still very tiny: their combined mass is less than half that of Triton, the largest moon of Neptune alone! Titania, Uranus largest satellite, has a size of less than half of our Moon. These small sizes combined with the distance from us and the low surface albedo, make the Moons of Uranus very faint to be observed, with a brightness variation between 13.9 of Titania to only 16.5 of Miranda, the Moon barely visible in the "glare" of Uranus.
Despite requiring 84 Earth years to complete a full rotation around the Sun, at high telescopic power the proper motion of Uranus is still well noticeable comparing the background stars. In this animation, covering about an hour of time, the telescope was tracking Uranus so it was the star to the left (a star of Mag. 13.6 named by its GAIA catalogue number) showing this proper motion over the imaging period.
C14 + Siebert 1.5x (@ f/16) - ZWO ASI290MM - iOptron CEM120 - Singapore
