Observations of Five Major Uranian Satellites during 2013-2020 Based on Gaia DR3

A total of 10,339 positions of the five major Uranian satellites (Ariel, Umbriel, Titania, Oberon and Miranda) were collected at the Yunnan Observatories from 2013 to 2020 with the 1.0 m astrometric reflector. A median filtering method was applied to reduce the influence of the bright Uranus halo. All CCD observational data was analyzed by the newly developed CCD image-processing software with Gaia DR3 as the reference catalog. The impact of different exposure times on satellite positioning accuracy was evaluated. The observational positions of satellites were compared with theoretical positions from Institut de M & eacute;canique C & eacute;leste et de Calcul des & Eacute;ph & eacute;m & eacute;rides (DE441 and Lainey et al. 2015) and the mean offsets are from -0.'' 115 to 0.'' 103 in both R.A. and decl. for the five satellites. The standard deviation of the offsets are from 0.'' 008 to 0.'' 086 for the four greatest Uranian satellites and from 0.'' 037 to 0.'' 132 for Miranda in each direction. These precise observations of the five major Uranian satellites over an 8 yr period will be very useful for improving the orbital parameters of both Uranus and its five major satellites.