Nautical Astronomical Almanac, 20192020
Preface
The Institute of Applied Astronomy of the RAS (IAA RAS) submits the next issue of "The Nautical Astronomical Almanac for the years 20192020" biennial (NAA2).
NAA2 is based on "The Nautical Astronomical Yearbook" (NAY) also prepared by IAA RAS. NAA2 provides an easy access to a useful navigational publication which is constantly present aboard a ship and has a longer period of validity as compared to standard navigational manuals. The Almanac does not require any other publications for observation processing and gives the same accuracy of basic astronomical parameters as NAY does. NAA2 contains detailed algorithms of solving the main navigational tasks, such as determination of the compass' correction and finding a ship's position by means of the Sun's and stars' observations. It also contains instructions for the use of the marine sextant, the celestial globe, star charts and the fixing position plotter for the determination of a ship's location.
The structure of "The Nautical Astronomical Almanac for the years 20192020" has not undergone essential changes in comparison with the previous issue of NAA2. The theoretical basis of ephemerides is the EPM2011/m theory of movement of the Solar system bodies created in IAA RAS. In accordance with the resolutions of XXIV and XXV General Assemblies of International Astronomical Union positions of stars are published in the system of FK6 and HIPPARCOS catalogues referred to International Celestial Reference System (ICRS) based on the observations of extragalactic radiosources. Thus, consistency is achieved between the data published in NAA2 and Russian "The Astronomical Yearbook" which is the basis for planning and carrying out astronomical and geodetic programs. The Explanation and part of auxiliary tables are given in both Russian and English versions. The detailed description of theoretical basis of modern astronomical ephemerides, as well as algorithms for their calculation may be found in "The Expanded explanation to the Astronomical Yearbook" published in "Transactions of IAA RAS", 2004, v.10 (in Russian).
The basic contents of the Almanac are daily tables. They include ephemerides of hour angles of the first point of Aries, the Sun and the Moon, declinations of the Sun and the Moon for each hour, and also hour angles and declinations of planets (Venus, Mars, Jupiter and Saturn) with a 5 hour step and to within 0.1'. Besides, time of sunrises and sunsets are given for 68 values of latitude. Azimuths of the upper limb of the Sun for risings and the opportunity time of the beginning of morning and evening observations of stars are also included.
The apparent places of 160 navigational stars are given for the beginning of each month in a special table, with the apparent places of 77 brightest stars being available in daily tables for every three days of a year (accuracy 0.1'). The tables of azimuths of Polaris (Pole star) are given with accuracy 0.1°.
NAA2 contains brief data on solar and lunar eclipses, configurations of planets, phases of the Moon and dates of the beginning of astronomical seasons. It also contains tables for the calculation of time of moonrises and moonsets to within 0.1h according to the time of lunar culmination and latitude of the observer. There are some auxiliary tables for interpolation and calculation of altitude and azimuth in NAA2.
Calculations of ephemerides in NAA2 for 20192020 have been executed by the following researchers of Laboratory of Astronomical Yearbooks of IAA RAS:

hour angles of the first point of Aries, coordinates of the Sun, Moon, and planets, the moments of culminations, parallaxes, visible semidiameters and phases of the Moon, configurations of planets, the beginnings of seasons  N.I.Glebova;

conditions of visibility of planets, apparent places of stars, tables of azimuths of Polaris  M.L.Sveshnikov, G.A. Kosmodamianskij;

the time of sunrises and sunsets, azimuths of the upper limb of the Sun for the time of sunrise, the time of the beginning of morning and evening observations, tables of corrections to the times of the culmination of the Moon for calculation of moonrises and moonsets, eclipses of the Sun and the Moon  M.V.Lukashova.
The Explanation for NAA2 (20192020) is revised by M.V. Lukashova, G.A. Kosmodamianskij. Such issues as the application of the marine sextant, the use of the celestial globe and star charts are also included into NAA2, as well as the universal altitude correction form and a fixing position plotter. Examples for NAA2 are calculated by M.V. Lukashova, M.L. Sveshnikov, G.A. Kosmodamianskij. The data control over various sections of NAA2 is made by G.A. Kosmodamianskij, N.I. Glebova, M.V. Lukashova, M.L. Sveshnikov, I.A. Lebedeva, and N.K. Omel'yanchuk.
G.A. Kosmodamianskij, M.V. Lukashova have prepared the original of the Explanation for NAA2. Presentation of the fixing position plotter, star charts and diagrams of visibility of planets in PSformat is made by M.L.Sveshnikov. Editing version of the tables has been made by D.A. Ryzhkova using systems of makingup tabulated editions "PUBLISHER" developed in IAA RAS.
The work of editing the Almanac has been headed by G.A. Kosmodamianskij, editorinchief, with active participation of all the researchers of the Laboratory.
In IAA RAS within the framework of creation of the electronic version of NAA2 the first version of the remote access system of "The Navigator" is developed. It is intended for the solving basic astronavigation tasks included in the explanations of NAA2. The solving of tasks is carried out in accordance with the accepted in this edition accuracy (0.1') and format of protocols of the solutions for examples published in it (M.V.Lukashova, M.L.Sveshnikov, G.A. Kosmodamianskij). The system "The Navigator" is available from the Internet: http://shturman.ipa.nw.ru.
In conformity with the STCW95 Code provisions, every navigator should be able to use classic methods of Nautical Astronomy. Therefore, they will undoubtedly appreciate the new "Nautical Astronomical Almanac" presented.
"The Nautical Astronomical Almanac" has been approved by Department of Navigation Safety of the State Marine Fleet Service (ROSMORFLOT) of Ministry of Transport of the Russian Federation, and it is recommended for navigators in the Russian Federation.
Contents
Preface and Explanation for the Nautical Astronomical Almanac (in Russian)  4 
Daily tables for 20192020  26 
Stars. Apparent places for 20192020  270 
Table 11. Conversion of arc to time  300 
Tables of increments and corrections  301 
Tables for calculation of altitudes and azimuths (TAA57)  334 
Preface (in English)  349 
The explanatory notes to Russian terms in daily tables  351 
Calendar for 20192021  352 
Explanation for the Nautical Astronomical Almanac (in English)  353 
Introduction  353 
Notation  354 
Basic relations and formulae  355 
Hour angles, declinations and sidereal hour angles  356 
Risings, settings and the upper culminations of the Sun, time of beginning of observations  357 
Azimuths of apparent sunrises and sunsets  359 
Moonrises, moonsets and culminations of the Moon  360 
Determination of latitude by Polaris (Pole star)  361 
Use of NAA2 in 2021  361 
The celestial globe  363 
Charts of the sky of stars. The index to stars  363 
Diagrams of visibility of planets for 20192020  368 
Sextant. Checking and determination of index error  370 
Recommendations for measuring the altitudes of stars with the sextant  371 
Planet configurations and other astronomical phenomena for 20192020  372 
Azimuth of Polaris for 20192020  374 
The table 1. Corrections to time of upper culmination of the Moon  376 
The table 2. Corrections to azimuths of apparent solar upper limb at sunrise and sunset  378 
The table 3. Corrections to time of sunrise and sunset, time of beginning of observations, and the culminations of celestial bodies  378 
The table 4. Dip of horizon  380 
The table 5. Mean refraction  380 
The table 6. Form of reduction of altitudes  380 
The table 7. Correction to altitude for temperature О”HT  381 
The table 8. Correction to altitude for atmospheric pressure О”HP  381 
The table 9. Correction to altitude for semidiameter and parallax of the Sun  381 
The table 10. Reduction of altitudes to the fixed place (zenith)  381 
Determination of the compass' correction  382 
Determination of the position of a ship by observations of stars  384 
Determination of the position of a ship by observations of the Sun  386 
Algorithms of Calculating altitudes and azimuths (TAA57)  388 