The ASC is a compilation produced for the Gaia mission. We have combined data from the following catalogs or datasets to produce a homogenous list of positions, proper motions, photometry in a blue and red band and estimates of the magnitudes in the Gaia G and G_RVS bands: Tycho2, UCAC4, Hipparcos, PPMXL, GSC2.3 and Sky2000. Originally ASC sources were selected from the Initial Gaia Source List (IGSL, <A HREF="http://cdsarc.u-strasbg.fr/cgi-bin/Cat?I/324">I/324</A>). However, here we produce a cleaner catalog starting from the bright source catalogs and using the following criteria: 1) The candidate must be in the Tycho2, UCAC4, Hipparcos or Sky2000 catalog. 2) The Gaia G magnitude must be brighter than 13.4. 3) The star must be isolated from other objects of similar magnitudes 4) The object must not be in the Washington Double Star catalog 5) If a healpix 6th region has more than 1000 objects the magnitude limit is reduced to reduce the number of objects in that region. Since the ASC was produced independently from the IGSL using different procedures there is not a direct 1 to 1 match between ASC and IGSL entries. We have matched the ASC to the IGSL and found that 9 out of the 8 million entries do not have a clear match. Since there may still remain ambiguous matches in the 8 million matched objects, we decided to assign the sourceIDs of the IGSL with the adjustment that the runningnumber is equal to the IGSL runningnumber + 320000. Included Catalogs: Tycho2, UCAC4, Sky2000, HIPPARCOS for candidates and the PPMXL, GSC2.3 were used to calculating magnitudes.
Positions of Mars obtained in Nikolaev Astronomical Observatory
Short Name:
Mars_pos
Date:
05 Dec 2018 17:51:36
Publisher:
Nikolaev Astronomical Observatory
Description:
Observations of Mars were carried out with the Zonal Astrograph at Nikolaev Astronomical Observatory. The mean period of observations in opposition was 156 days. The orbits of Mars and Earth were covered 7.3 and 3.8 times respectively. After defining more exactly some computational elements and the planet's phase, 441 positions were obtained in ICRS system. Coordinates of reference stars were taken from Hipparcos and Tycho catalogues, and their proper motions were taken from the ACTRC catalogue. The standard errors in right ascension and declination are ±0."21 and ±0."22 respectively, in accordance with accuracy estimations of the Institute of Applied Astronomy of the Russian Academy of Science. These standard errors are the best among all known photographic observations of Mars. Topocentric right ascension, declination in ICRS system (J2000.0), and Julian Days (UTC) are given in the table.
