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We present new isochrone fits to colour-magnitude diagrams of the Galactic globular cluster NGC 5904 (M5). We utilise 29 photometric bands from the ultraviolet to midinfrared by use of the data from the Hubble Space Telescope, Gaia DR2, Wide-field Infrared Survey Explorer, Sloan Digital Sky Survey (SDSS), and other photometric data. In our isochrone fitting we use the PAdova and TRieste Stellar Evolution Code, the MESA Isochrones and Stellar Tracks, the Dartmouth Stellar Evolution Program, and a Bag of Stellar Tracks and Isochrones both for the solar-scaled and enhanced He and α abundances with a metallicity about [Fe/H]= −1.33 adopted from the literature. All tools provide us with estimates of the distance, age, and extinction law to the cluster. The best-fit distance, true distance modulus, and age are 7.4 ± 0.3 kpc, 14.34 ± 0.09 mag, and 12.15 ± 1.00 Gyr, respectively. The derived distance agrees with the literature, including the Gaia DR2 parallax with its known global zero-point correction. All the data and models, except some UV and SDSS data, agree with the extinction law of Cardelli-Clayton-Mathis with R V = 3.60 ± 0.05 and A V = 0.20 ± 0.02 mag. This extinction is twice as high as generally accepted due to a rather high extinction between 625 and 2000 nm. An offset of the model colours instead of the high extinction in this range is a less likely, yet possible explanation of the discovered large deviations of the isochrones from the data.

Context. We present a remeasurement of old photographic plates, providing important raw data for dynamical studies of the Saturnian satellite system. The unprecedentedly accurate realization of the Gaia reference frame allows us to make a precise calibration of digitized astronegatives of the Saturnian satellite images. Aims. We reprocessed 357 astronegatives taken with the 26-inch refractor and the normal astrograph of the Pulkovo Observatory between 1972 and 2007 to obtain the positions of the main Saturnian moons in the second Gaia data release (Gaia DR2) system. Methods. Photographic plates were digitized with the Pulkovo Mobile Digitizing Device scanner. The New Astrometric Reduction of Old Observations digitizer at the Paris Observatory was used to calibrate the scanned images. Satellite image centering and astrometric reduction were performed. Results. In total, 6487 positions (equatorial coordinates) have been determined with an accuracy of 50 mas. This is confirmed by a comparison of our data with modern ephemerides. The verification of the results was performed using data from past close approaches by Saturnian satellites to Gaia reference stars, showing the adequacy of the current residual analysis. A joint review of the Pulkovo and the United States Naval Observatory intersatellite positions allows us to conclude about the existence of faint systematic effects in the satellite theories of motions at the 10 mas level.

A set of ≈8 million single stars of the UCAC3 catalogue has been analysed. It contains stars with reliable proper motions with not less than three epochs of observations used to compute the proper motion. Our main goal is to investigate the inertiality of the reference system defined by ‘good’ stars of the UCAC3 catalogue. The formalism of vectorial spherical harmonics has been applied to analyse the system of proper motions of the selected UCAC3 stars. A comparison between the results of solutions for several subsets of UCAC3 stars shows that the key parameters significantly change with stellar magnitudes, colours and average distances. The values of the components of the rigid‐body rotation vector of the Hipparcos Celestial Reference Frame (HCRF) with respect to extragalactic sources were determined using ‘proper motions’ of more than 8000 galaxies of the UCAC3 catalogue. The values are ω1= 0.58 ± 0.15, ω2=−1.02 ± 0.15, ω3=−0.59 ± 0.17 mas yr−1 in galactic coordinates. Traces of the considerable magnitude equation are seen in the ‘proper motions’ of the UCAC3 galaxies. The most significant component derived from the analysis of the UCAC3 galaxies is ω2. It does not contradict the results of the analysis of the proper motions of selected stars (ω2=−1.09 ± 0.02 mas yr−1).