A transit is the passage of a planet across the Sun's bright disk. At this time, the planet can be seen as a small black disk slowly moving in front of the Sun. The orbits of Mercury and Venus lie inside Earth's orbit, so they are the only planets which can pass between Earth and Sun to produce a transit. Transits are very rare astronomical events. In the case of Mercury, there are on average thirteen transits each century. A transit of Mercury occurs only if the planet is in inferior conjunction with the Sun (between Earth and Sun) and is also crossing the through Earth's orbital plane (the Ecliptic). During the present period in Earth's history, Mercury's orbit crosses Earth's orbital plane in early May and early November each year. If the Mercury is passing between the Earth and Sun at that time, a transit will be seen.
During the seven century period 1601 CE to 2300 CE1, Earth experiences 94 transits of Mercury across the Sun. These events can be organized into two groups:
All Transits = 94 = 100.0%
May (Descending Node2) = 31 = 33.0 %
November (Ascending Node3) = 63 = 67.0 %
Mercury's orbit is highly eccentric (e = 0.2056). This causes the little planet's distance from the Sun to vary from 46 to 70 million kilometers. At perihelion4, Mercury's orbital velocity (59.0 km/sec) is over 50% faster than it is at aphelion5 (38.9 km/sec). Furthermore, the planet's orbit is tipped 7 degrees to Earth's around the Sun. Such a wildly varying and inclined orbit has important consequences on the characteristics and frequency of Mercury's transits.
During May transits, the apparent diameters of the Sun and Mercury are 1902 and 12 arc-seconds, respectively. Thus, Mercury appears to be 1/158 the size of the Sun. In contrast, the apparent diameters of the Sun and Mercury during November transits are 1937 and 10 arc-seconds, respectively. So then Mercury appears to be 1/194 the size of the Sun.
A cursory examination to the table below will reveal that consecutive transits of Mercury appear to be separated by either 3.5, 7, 9.5, 10 or 13 years. The pattern is rather complex because of Mercury's elliptical orbit. The shorter periods are a consequence of several longer harmonics between the orbital periods of Mercury and Earth. The 13 year period is of particular note because it corresponds to nearly 54 orbits of Mercury around the Sun (it falls short of a perfect fit by just 2.01 days). A longer period of 33 years (10 + 10 + 13) produces an even better fit which corresponds to 137 orbits of Mercury minus 1.67 days. If one combines the 13 year and 33 year periods together, the 46 year total equals 191 orbits of Mercury plus only 0.34 days.
A useful way to organize the Mercury's transits is by grouping them into series where each member is separated by 16,802 days or 46 years (= sum of 13 and 33 years). Thus, the transits of 1957, 2003 and 2049 belong to one series, while the transits of 1960, 2006 and 2052 belong to another series. May transits occur about a month after Mercury's aphelion passage so the planet is traveling at close to its minimum velocity. The planet's relative position with respect to the Sun shifts by approximately 200 arc-seconds with each transit. This rapidly evolving geometry means that transit series which occur in May only last about 10 cycles or 414 years. In comparison, November transits occur just a few days before Mercury reaches perihelion so the planet is traveling at nearly its maximum orbital velocity. Mercury's relative position with respect to the Sun shifts by only about 100 arc-seconds with each transit, so November series last about twice as long as a May series. For example, Series 8 (November at Ascending Node) began in 1776 and will run through 2604 for a total of 19 transits spanning 828 years. For comparison, Series 9 (May at Descending Node) began just recently in 1957 and will run through 2371 for a total of 10 transits spanning 414 years. At any one time, there can be about six transit series running concurrently. But since the November series last twice as long as the May series, there are twice as many transits in November as there are in May. Mercury's transit series are quite analogous to the Saros series for solar and lunar eclipses although they are shorter and to not have as many events in each series.
The following catalog contains predictions for every transit of Mercury during the seven hundred year period 1601 CE through 2300 CE. The information for each transit in the catalog is summarized as follows. The calendar date6 and geocentric Universal Time7 of the four transit contacts8 and the instant of greatest transit9 are found in the first six columns. The Sun's coordinates (Right Ascension and Declination) and the Greenwich Sidereal Time at 00:00 UT are given next. The minimum separation between the centers of Mercury and the Sun is listed in arc-seconds. Finally the transit series10 is given.
The individual columns in each table are described in greater detail in the Key to Transit Catalogs.
Transit Contact Times (UT)
------------------------------------- Minimum Sun Sun Transit
Date I II Greatest III IV Sep. RA Dec GST Series
h:m h:m h:m h:m h:m " h ° h
1605 Nov 01 18:43 18:47 20:02 21:18 21:21 855.9 14.471 -14.68 2.739 6
1615 May 03 06:41 06:44 10:09 13:33 13:36 468.4 2.666 15.61 14.725 5
1618 Nov 04 11:08 11:10 13:42 16:14 16:15 352.8 14.642 -15.49 2.909 4
1628 May 05 14:19 14:23 17:32 20:40 20:44 571.0 2.869 16.52 14.933 3
1631 Nov 07 04:38 04:39 07:20 10:01 10:03 146.4 14.814 -16.27 3.079 2
1644 Nov 09 22:53 22:55 00:57 02:58 03:00 641.1 14.987 -17.02 3.249 1
1651 Nov 03 23:07 23:09 00:52 02:35 02:38 750.7 14.540 -15.01 2.809 6
1661 May 03 13:05 13:08 16:54 20:40 20:43 263.2 2.740 15.94 14.800 5
1664 Nov 04 15:53 15:54 18:32 21:10 21:11 250.4 14.711 -15.81 2.979 4
1674 May 07 21:56 22:01 00:16 02:31 02:37 775.4 2.943 16.84 15.008 3
1677 Nov 07 09:32 09:33 12:11 14:48 14:50 248.7 14.884 -16.58 3.149 2
1690 Nov 10 03:57 03:59 05:43 07:27 07:29 742.1 15.057 -17.32 3.318 1
1697 Nov 03 03:38 03:40 05:42 07:43 07:45 647.1 14.610 -15.33 2.878 6
1707 May 05 19:34 19:37 23:32 03:27 03:30 64.5 2.813 16.27 14.875 5
1710 Nov 06 20:39 20:40 23:22 02:03 02:05 145.2 14.781 -16.12 3.048 4
1723 Nov 09 14:25 14:27 16:59 19:30 19:32 350.6 14.953 -16.87 3.218 2
1736 Nov 11 09:07 09:11 10:30 11:49 11:52 843.0 15.128 -17.59 3.388 1
1740 May 02 21:34 21:42 23:02 00:21 00:29 888.8 2.685 15.68 14.742 7
1743 Nov 05 08:12 08:15 10:30 12:45 12:47 542.4 14.679 -15.65 2.948 6
1753 May 06 02:16 02:19 06:13 10:06 10:09 138.6 2.888 16.59 14.949 5
1756 Nov 07 01:26 01:28 04:10 06:54 06:55 42.6 14.851 -16.42 3.118 4
1769 Nov 09 19:21 19:23 21:46 00:10 00:12 454.0 15.024 -17.17 3.288 2
1776 Nov 02 20:55 21:03 21:36 22:09 22:17 943.8 14.522 -14.91 2.793 8
1782 Nov 12 14:35 14:42 15:16 15:50 15:57 944.6 15.199 -17.88 3.457 1
1786 May 04 02:56 03:01 05:41 08:21 08:26 689.0 2.759 16.02 14.817 7
1789 Nov 05 12:51 12:53 15:19 17:44 17:46 439.9 14.748 -15.96 3.018 6
1799 May 07 09:07 09:10 12:50 16:31 16:34 339.5 2.961 16.90 15.024 5
Transit Contact Times (UT)
------------------------------------- Minimum Sun Sun Transit
Date I II Greatest III IV Sep. RA Dec GST Series
h:m h:m h:m h:m h:m " h ° h
1802 Nov 09 06:14 06:16 08:58 11:41 11:43 60.9 14.921 -16.73 3.188 4
1815 Nov 12 00:18 00:20 02:33 04:46 04:48 556.1 15.094 -17.45 3.357 2
1822 Nov 05 01:00 01:04 02:25 03:45 03:49 838.8 14.646 -15.50 2.917 8
1832 May 05 09:00 09:04 12:25 15:47 15:50 484.7 2.833 16.34 14.892 7
1835 Nov 07 17:33 17:35 20:08 22:41 22:43 336.4 14.817 -16.27 3.087 6
1845 May 08 16:20 16:24 19:37 22:49 22:53 547.2 3.037 17.21 15.099 5
1848 Nov 09 11:05 11:07 13:48 16:28 16:30 163.0 14.991 -17.02 3.257 4
1861 Nov 12 05:18 05:21 07:19 09:18 09:21 657.9 15.166 -17.74 3.427 2
1868 Nov 05 05:26 05:28 07:14 09:00 09:03 735.1 14.715 -15.81 2.987 8
1878 May 06 15:13 15:16 19:00 22:44 22:47 287.3 2.907 16.66 14.966 7
1881 Nov 08 22:17 22:19 00:57 03:36 03:38 231.8 14.888 -16.58 3.157 6
1891 May 10 23:57 23:57 02:22 04:47 04:47 753.6 3.112 17.52 15.174 5
1894 Nov 10 15:56 15:58 18:35 21:11 21:13 266.2 15.061 -17.31 3.327 4
1907 Nov 14 10:24 10:26 12:07 13:47 13:50 758.6 15.236 -18.01 3.496 2
1914 Nov 07 09:57 09:59 12:03 14:07 14:09 630.7 14.785 -16.12 3.056 8
1924 May 08 21:44 21:47 01:41 05:35 05:38 84.6 2.981 16.97 15.041 7
1927 Nov 10 03:02 03:04 05:46 08:27 08:29 128.7 14.958 -16.87 3.226 6
1937 May 11 08:53 - 08:59 - 09:06 955.5 3.187 17.81 15.248 5
1940 Nov 11 20:49 20:51 23:21 01:52 01:53 368.5 15.132 -17.59 3.396 4
1953 Nov 14 15:37 15:41 16:54 18:07 18:11 861.8 15.308 -18.28 3.566 2
1957 May 06 23:59 00:09 01:14 02:20 02:30 907.3 2.852 16.41 14.909 9
1960 Nov 07 14:34 14:36 16:53 19:10 19:12 527.9 14.855 -16.42 3.126 8
1970 May 09 04:19 04:22 08:16 12:10 12:13 114.1 3.056 17.28 15.115 7
1973 Nov 10 07:47 07:49 10:32 13:16 13:17 26.4 15.028 -17.17 3.296 6
1986 Nov 13 01:43 01:45 04:07 06:29 06:31 470.5 15.203 -17.87 3.466 4
1993 Nov 06 03:06 03:12 03:57 04:41 04:47 926.7 14.753 -15.97 3.025 10
1999 Nov 15 21:15 21:30 21:41 21:52 22:07 963.0 15.379 -18.54 3.635 2
Transit Contact Times (UT)
------------------------------------- Minimum Sun Sun Transit
Date I II Greatest III IV Sep. RA Dec GST Series
h:m h:m h:m h:m h:m " h ° h
2003 May 07 05:13 05:17 07:52 10:27 10:32 708.3 2.926 16.73 14.983 9
2006 Nov 08 19:12 19:14 21:41 00:08 00:10 422.9 14.925 -16.73 3.196 8
2016 May 09 11:12 11:15 14:57 18:39 18:42 318.5 3.130 17.58 15.190 7
2019 Nov 11 12:35 12:37 15:20 18:02 18:04 75.9 15.098 -17.45 3.366 6
2032 Nov 13 06:41 06:43 08:54 11:05 11:07 572.1 15.274 -18.14 3.535 4
2039 Nov 07 07:17 07:21 08:46 10:12 10:15 822.3 14.822 -16.27 3.095 10
2049 May 07 11:03 11:07 14:24 17:41 17:44 511.8 3.000 17.04 15.058 9
2052 Nov 09 23:53 23:55 02:29 05:04 05:06 318.7 14.996 -17.02 3.265 8
2062 May 10 18:16 18:20 21:36 00:53 00:57 520.5 3.206 17.88 15.265 7
2065 Nov 11 17:24 17:26 20:06 22:46 22:48 180.7 15.170 -17.73 3.435 6
2078 Nov 14 11:42 11:44 13:41 15:37 15:39 674.3 15.345 -18.41 3.605 4
2085 Nov 07 11:42 11:45 13:34 15:24 15:26 718.5 14.893 -16.58 3.165 10
2095 May 08 17:20 17:24 21:05 00:47 00:50 309.8 3.075 17.35 15.133 9
2098 Nov 10 04:35 04:37 07:16 09:56 09:57 214.7 15.066 -17.31 3.335 8
2108 May 12 01:40 01:44 04:16 06:47 06:52 724.7 3.281 18.16 15.340 7
2111 Nov 14 22:15 22:17 00:53 03:29 03:30 283.3 15.241 -18.01 3.505 6
2124 Nov 15 16:49 16:52 18:28 20:04 20:07 778.9 15.418 -18.67 3.674 4
2131 Nov 09 16:14 16:16 18:22 20:29 20:31 614.4 14.962 -16.87 3.234 10
2141 May 10 23:46 23:50 03:43 07:36 07:39 108.1 3.151 17.65 15.207 9
2144 Nov 11 09:18 09:19 12:02 14:44 14:46 112.7 15.137 -17.59 3.404 8
2154 May 13 10:03 10:18 10:58 11:38 11:53 930.6 3.357 18.45 15.414 7
2157 Nov 14 03:08 03:10 05:40 08:09 08:11 386.9 15.313 -18.28 3.574 6
2170 Nov 16 22:05 22:09 23:15 00:22 00:26 880.4 15.489 -18.92 3.744 4
2174 May 08 02:24 02:37 03:26 04:15 04:27 924.4 3.021 17.12 15.076 11
2177 Nov 09 20:48 20:50 23:09 01:28 01:30 509.8 15.033 -17.17 3.304 10
2187 May 11 06:27 06:30 10:24 14:18 14:21 96.0 3.226 17.94 15.282 9
2190 Nov 12 14:03 14:05 16:48 19:32 19:33 9.1 15.207 -17.87 3.474 8
2203 Nov 16 08:04 08:06 10:27 12:47 12:49 488.6 15.384 -18.54 3.644 6
2210 Nov 09 09:14 09:19 10:13 11:06 11:11 911.0 14.930 -16.73 3.203 12
2220 May 09 07:23 07:27 09:56 12:25 12:30 728.5 3.095 17.41 15.150 11
2223 Nov 12 01:25 01:27 03:55 06:24 06:26 406.5 15.103 -17.45 3.373 10
2233 May 12 13:13 13:16 16:59 20:43 20:46 296.2 3.301 18.23 15.357 9
2236 Nov 13 18:50 18:52 21:35 00:17 00:19 95.4 15.279 -18.14 3.543 8
2249 Nov 16 13:02 13:04 15:12 17:21 17:23 591.6 15.456 -18.80 3.713 6
2256 Nov 09 13:26 13:29 14:59 16:29 16:32 807.4 15.000 -17.02 3.273 12
2266 May 10 13:16 13:20 16:34 19:47 19:51 529.7 3.170 17.71 15.225 11
2269 Nov 12 06:04 06:06 08:42 11:17 11:19 302.5 15.175 -17.73 3.443 10
2279 May 13 20:14 20:18 23:38 02:57 03:01 499.5 3.376 18.50 15.431 9
2282 Nov 15 23:41 23:41 02:22 05:02 05:02 197.9 15.350 -18.41 3.613 8
2295 Nov 17 18:03 18:06 19:59 21:52 21:54 694.6 15.528 -19.04 3.783 6
The Julian calendar is used for all dates up to 1582 Oct 04. After that date, the Gregorian calendar is used. Due to the Gregorian Calendar reform, the day after 1582 Oct 04 (Julian calendar) is 1582 Oct 15 (Gregorian calendar). Note that Great Britain did not adopt the Gregorian calendar until 1752. For more information, see Julian and Gregorian Calendars.
To determine whether a transit is visible from a specific geographic location, it is simply a matter of calculating the Sun's altitude and azimuth during each phase of the transit. The calculations can be performed on any pocket calculator having trig functions (SIN, COS, TAN). Armed with the latitude and longitude of the location, the transit catalog provides all the additional information needed to make the calculations. For the equations and an example of how to calculate the Sun's altitude for a specific location, see Transit Visibility.
As an aid to historical research, two Excel 97 spreadsheet files have been prepared which perform the above calculations automatically. You simply enter the location name, latitude and longitude. Each of the tables then calculates the altitude of the Sun at that location for every contact for several dozen of transits. The two tables are similar but cover different time periods:
Please note that these files will not open properly unless you have Excel 97 (or newer) installed on your computer. When each of the spreadsheets is downloaded, it will be opened automatically in Excel where you will be able to enter the coordinates of any geographic location to calculate the transit circumstances. The spreadsheets are protected so that you can not accidently delete or edit any information required by the calculations. Only the name and coordinates of the geographic location (in the green box of each spreadsheet) may be modified.
The transit times in these tables are based of geocentric calculations. Because of parallax, the observed transit times for any given location may differ by up to 3 minutes. Furthermore, the Sun's actual altitude at a location may differ by up to 1 degree from the tables. Such precision is adequate for many applications especially since the geocentric approximation greatly simplifies the circumstances calculations.
All transit calculations are by Fred Espenak, and he assumes full responsibility for their accuracy. Besselian elements for the transit predictions are from "Transits" by Jean Meeus (Willmann-Bell, 1989). This is an indispensable reference for anyone wishing to do transit calculations.
Special thanks to eclipse chaser Michael Gill for enthusiastically and rigorously beta-testing this page and for catching typographic errors. (2003 March)
Permission is freely granted to reproduce this data when accompanied by an acknowledgment:
"Transit Predictions by Fred Espenak, NASA/GSFC"
