Sections

Astronomical Yearbook for 2021

Preface

In the "Astronomical Yearbook" (AY) the ephemerides of the Sun, Moon, major planets and stars computed with the maximum precision in accordance with the resolutions approved by the International Astronomical Union (IAU) are published. The information is also given on various astronomical phenomena - lunar and solar eclipses, planetary configurations, rises and sets of the Sun and Moon, etc. The explanation, contained the examples, illustrates the possibility of the calculation of various ephemerides to any particular time and for the any observation place.

Since issue for 2004 the reform AY was carried out connected to change of ephemerical basis AY according to Recommendations XXIII-XXIV General assemblies (GA) IAU. In the course several years full replacement of theories of movement of major planets and the Moon, of the precession-nutation models, of the star catalogue is stage by stage made. The system of coordinates based on the new concept of "the non-rotating origin" is entered. Separate stages of reform are described in forewords and explanations to the Yearbooks on 2004-2008. Change of an ephemeris basis - replacement of the theory of EPM2004 by EPM2011/m created in IAA RAS, became the last stage of work.

Preparation of the AE-2021 ephemerides is based on the following data:

  • The fundamental ephemerides of the Sun, the Moon and major planets are calculated on the theory EPM2011/m developed at IAA RAS. This theory present the movement of these objects with accuracy enough for the theoretical and practical applications. The differences between the theories EPM2011/m and DE405/LE405 in common use developed at the JPL (Jet Propulsion Laboratory, Pasadena, USA) are less on the order than the accuracy of the data published in AY for these bodies.
  • In accordance with the IAU2000 resolution the parameters of the nutation in longitude and declination are calculated under the IAU2000_R06 nutation theory (Note of IERS Conventions Center, 16 June 2009).
  • The account of precession was carried out in the Lieske method of parameterization with values of polynomial coefficients corresponding the new precession model P03 resulted in the report of Working group of IAU on precession and the ecliptic (2006).
  • Calculation the sidereal time is made with use "the Siderial Angle" and new expression for the equation of equinoxes accepted by "IERS Convention (2003)", and P03 precession theory.
  • The shift of average pole J2000.0 relative to the pole ICRS is taken into account at calculation of elements of the precession-nutation matrix.
  • Calculing the stars ephemerides the fundamental catalog FK6 was used. The ephemerides of the stars which have not in this catalog are based on the catalog HIPPARCOS. Both catalogues are in ICRS. Calculating the corrections for orbital movement of double stars "Fourth catalog of orbits of visual binary stars" WH-4 was used.
  • The ephemeris data of the Yearbook are given in the classical concept of equinox. According to the recommendation XXIV GA IAU (resolution B1.7) the data connected with the new Celestial Intermediate Reference System (CIRS), and elements of a matrix of transition from ICRS to the celestial intermediate origin CIO and true equator of date are given.

All ephemeris data are calculated by means of the PS BOOKA edition package of a updated multi-purpose program complex the ERA-8 developed in IAA of RAS for the decision of problems of ephemeris astronomy. The updated program complex ERA-8 (Pavlov D.A., Skripnichenko V.I. First results of trial operation of the cross-platform version of ERA system // Works IAA of RAS, SPb.: Science, 2014. Vyp.30. Page 32-40) is included in program BOOKA system which is used for calculation of ephemerises for the IAA printing editions of RAS.

In "The Astronomical Yearbook for 2021" the calculation of the ephemeris data was carried out by following collaborators of the laboratory of astronomical yearbooks:

  • the sidereal time - N.I. Glebova, M.L. Sveshnikov;
  • the ephemerides of the geocentric coordinates of the Sun, the geocentric and heliocentric coordinates of the major planets, osculating elements of the planet orbits, the ephemerides of the position and velocity of the Earth in the barycentric reference system, the elements of the precession matrix and of the nutation matrix, the terms by reductions, the ephemerides for physical observations of the Moon, the phases of the Moon, perigee and apogee - N.I. Glebova;
  • the ephemerides of the geocentric coordinates of the Moon, and coefficients of the Tchebyshev polynomials - N.I. Glebova, D.A. Pavlov;
  • the seasons and precession values, the planetary configurations - N.I. Glebova;
  • the data for the eclipses of the Sun and Moon - M.V. Lukashova;
  • the data for the occultations of planets by the Moon - G.A. Kosmodamianskij;
  • the ephemerides for physical observations of the Sun, planets and Saturn's rings - G.A. Kosmodamianskij, M.L. Sveshnikov;
  • the times of rise and set of the Sun and Moon - M.V. Lukashova;
  • mean places of stars at J2000.0, the table of the corrections for the orbital motion of stars - M.L. Sveshnikov, N.I. Glebova;
  • the mean places of stars on epoch of the year, the apparent places of the tenday and circumpolar stars - N.I. Glebova;
  • the tables for altitudes and azimuths of Polaris and the tables for latitude determinations from observations of Polaris - G.A. Kosmodamianskij, M.L. Sveshnikov;
  • Earth rotation angle, Equation of the Origins, the CIP parameters, matrix elements for conversion from ICRS to CIO and true equator of date - N.I. Glebova, M.L. Sveshnikov;

The data control was carried out by N.I. Glebova, N.K. Omelyanchuk, and I.A. Lebedeva.

The explanation to the Yearbook is processed by N.I. Glebova, N. B. Zheleznov, and M.L. Sveshnikov. The additional information on algorithms of calculation of ephemerides published in AY is given in "The Explanatory Supplement to "the Astronomical Yearbook" ("Transactions of IAA of RAS", 2004, vol.10). The examples in the Explanation were carried out by N.I. Glebova, G.A. Kosmodamianskij, M.V. Lukashova, and M.L. Sveshnikov. The Explanation in the TEX was carried out by N.I. Glebova, M.V. Lukashova, and N.K. Omelyanchuk.

Since 1995 the publication of the "Astronomical Yearbook" was carried out by means of the softwares "SVITA" and "PUBLISHER" (G.A. Netsvetaeva. PUBLISHER - integrated environment for support astronomical yearbook issue, Communications of IAA of RAS. 2010, в„–В 187). The same systems are used by preparation of the AE application on the Internet.

The layout of "The Astronomical Yearbook for 2021" was carried out by D.A. Ryzhkova.

Contents

Preface 3
Seasons, some constants 5
Sidereal time 6
Ephemeris of the Sun 10
Rectangular equatorial coordinates of the Sun 26
Aberration, parallax, mean longitude of the Sun, obliquity of the ecliptic, nutation in obliquity 34
Mean longitude of the Moon, mean elements of the Moon's orbit and equator 35
Ephemeris of the Moon 36
Right ascension, declination and geocentric distance of the Moon 52
Coefficients of the Tchebyshev polynomials, the Moon 60
Phases of the Moon, perigee and apogee 60
Heliocentric coordinates of the planets 61
Osculating elements of the internal planets 66
Osculating elements of the outer planets 67
Ephemeris of Mercury 68
Ephemeris of Venus 76
Ephemeris of Mars 84
Ephemeris of Jupiter 92
Ephemeris of Saturn 100
Ephemeris of Uranus 108
Ephemeris of Neptune 116
Ephemeris of Pluto 124
Position and velocity of the Earth 126
Precession and nutation 127
Terms of reductions at 0h Terrestrial Time 142
Eclipses 150
Planetary configurations 160
Ephemeris for physical observations of the Sun 164
Ephemeris for physical observations of the Moon 168
Ephemeris for physical observations of Mercury 176
Ephemeris for physical observations of Venus 184
Ephemeris for physical observations of Mars 188
Ephemeris for physical observations of Jupiter 196
Physical data for the Sun, Moon, and major planets 203
Rotational elements of the planets 203
Ephemeris for physical observations of Saturn 204
Saturn's rings 210
Ephemeris for physical observations of Uranus 212
Ephemeris for physical observations of Neptune 214
Times of sunrise and sunset for latitudes from +30В° through +70В° 216
Times of moonrise and moonset for latitudes from +30В° through +70В° 224
Abbreviations of names of constellations 256
Abbreviations of names of catalogues 256
Mean places of stars (J2021.5) 257
Mean places of circumpolar stars (J2021.5) 271
Mean places of stars (ICRS) 272
Mean places of circumpolar stars (ICRS) 286
Terms of reductions for 0h of sidereal dynamical time 287
Second order terms of reductions 295
Apparent places of stars 299
Apparent places of circumpolar stars 482
Tables for latitude determinations from observations of Polaris 576
Table for altitudes and azimuths of Polaris 581
Earth rotation angle and Equation of the Origins 584
Celestial Intermediate Reference System 588
Matrix elements for conversion to CIRS 592
Auxiliary tables
I. Julian dates 601
IIa. Conversion of mean time to sidereal time (with accuracy 0.01s) 606
IIb. Conversion of sidereal time to mean time (with accuracy 0.01s) 607
IIIa. Conversion of mean time to sidereal time (with accuracy 0.001s and 0.0001s) 608
IIIb. Conversion of sidereal time to mean time (with accuracy 0.001s and 0.0001s) 609
IVa. Conversion of minutes and seconds to fractions of degree and back 610
IVb. Conversion of decimal parts of degree to minutes and seconds and back 611
V. Conversion of arc to time 612
VI. Conversion of minutes and seconds to parts of hour 612
VII. Conversion of hours, minutes and seconds to parts of day 613
VIIIa. Elements of PE-90 Earth's spheroid. Calculation geocentric coordinates of the Earth's surface points 614
VIIIb. Elements of IUGG Earth's spheroid. Calculation geocentric coordinates of the Earth's surface points 615
IX. Coefficients of Bessel's interpolation formula 616
X. Refraction (precision 1") 617
XI. Refraction (precision 0.1") 618
Explanation to Astronomical Yearbook for 2021
1. General remarks 619
2. Interpolation 628
3. Sidereal time 631
4. Transition from One Time Measure System to Another 632
5. Fundamental ephemeris of the Sun, the Moon, and major planets 636
6. Ephemeris of the Sun: the equatorial and ecliptical coordinates 638
7. Rectangular equatorial coordinates of the Sun 642
8. Mean elements of Sun's orbit. Mean elements of Moon's orbit and equator 643
9. Ephemeris of the Moon. Coefficients of the Tchebyshev polynomials. Phases of the Moon, perigee, apogee 643
10. Heliocentric coordinates of planets. Osculating elements 645
11. Ephemerides of the major planets 646
12. Position and velocity of the Earth. precession and nutation 648
13. Terms of reductions 650
14. Eclipses 651
15. Planetary configurations and other astronomical phenomena 655
16. Ephemeris for physical observations of the Sun 655
17. Ephemeris for physical observations of the Moon 656
18. Planetocentric and planetographic coordinates of the Earth and the Sun 657
19. Ephemeris for physical observations of planets 659
20. Saturn's rings 660
21. Times of rise and set of the Sun and Moon 661
22. Mean places of stars 662
23. Apparent places of stars 664
24. Apparent places of circumpolar stars 670
25. Tables for latitude determinations from observations of Polaris 675
26. Earth rotation angle and Equation of the Origins 676
27. Parameters of the Celestial Intermediate Reference System 677
28. Matrix elements for conversion from ICRS to CIRS 677
29. The application to the Astronomical yearbook for 2021 679
Index 680

Eclipses

May 26 Total lunar eclipse Description Visual path (for printing)
June 10 Annular solar eclipse Description Map (for printing)
November 19 Partial lunar eclipse Description Visual path (for printing)
December 4 Total solar eclipse Description Map (for printing)

Appendices