This chapter explores phenomena which occur very rarely, are visible over small geographical regions or are of very short duration.
Table 3.1: Bright Tri-Planetary Conjunctions (1500-2500 A.D.) <=60' Radius
MINIMUM SUM CONJUNCTIONS CIRCLE OF RADIUSYEAR PAIR 1 DATE SEP PAIR 2 DATE SEP INSCRIBE CIRCUM RATIO DATE SUN'S SEP1524 J-S JAN 31 46' M-S FEB 05 53' 15' 33' 2.2 FEB 05 +1h05m1563 V-S AUG 12 13 J-S AUG 25 7 21 48 2.2 AUG 10 -2h29m1564 V-S JUN 02 86 M-S JUN 03 43 19 49 2.6 JUN 03 +2h18m1564 V-J JUN 08 74 M-J JUN 13 32 25 54 2.2 JUN 08 +2h25m1682 M-S SEP 21 23 J-S OCT 24 15 20 49 2.4 SEP 22 -3h39m1769 V-J DEC 23 20 M-J DEC 24 46 21 48 2.3 DEC 26 -1h40m1802 J-S JUL 17 39 V-S JUL 26 17 24 59 2.4 JUL 26 +1h36m1819 M-S APR 26 45 V-S APR 28 38 18 49 2.7 APR 28 -1h30m1901 J-S NOV 28 26 M-S DEC 14 78 19 54 2.8 DEC 17 +1h17m1991 M-J JUN 14 37 V-J JUN 18 69 14 60 4.3 JUN 22 +2h36m2136 V-J SEP 22 87 M-J SEP 29 68 26 56 2.1 SEP 22 +1h20m2159 V-S DEC 03 20 J-S DEC 20 72 20 49 2.4 DEC 02 -2h52m2277 V-J AUG 02 71 M-J AUG 03 27 16 40 2.5 AUG 01 +0h59m2301 M-J DEC 05 6 V-J DEC 03 45 8 31 3.9 DEC 05 -3h37m2318 V-S APR 03 27 J-S APR 27 42 17 55 3.2 MAR 31 -1h01m2333 V-M APR 28 17 M-J MAY 07 74 26 58 2.2 MAY 02 +1h23m2378 M-S FEB 01 61 J-S FEB 18 49 11 51 4.6 JAN 28 +2h55m2378 V-S FEB 04 30 J-S FEB 18 49 18 44 2.4 FEB 02 +2h34m2477 V-S JUN 15 93 J-S JUL 06 6 25 55 2.2 JUN 14 +2h28mTable 3.1 lists all occasions from 1500-2500 when Venus (V), Mars (M), Jupiter (J) and Saturn (S) are in very close dual pair conjunctions. Dates prior to 1580 are on the Julian calendar; the latter are Gregorian. Each line gives the approximate date based on (12h) Universal time of minimum separation. As depicted in figure 1 below, an inscribed circle of radius is the radius of a circle inside the triangle formed by connecting the three planets near conjunction. A circumscribed radius is the smallest circle which can fit the three planets on its circumference. The minimum sum of both radii are used as the date of tightest grouping although lesser values of each type of radius may occur near this date. The closer the ratio of circumscribed to inscribed radii is to 2, the more the configuration will appear as an equilateral triangle. A side to side ratio (largest to smallest sides) of 25:1 will yield a circle of radii ratio of 5.7:1. Sun's separation: (+) for time planets set after sunset, (-) for time planets rise before sunrise for trio as seen from northern mid-latitudes. All events on the table are considered easily visible for several days before and after minimum separation.
The first factor concerns the degree of separation between the planets. In the most extreme case, a planet occults another. No planet on planet occultations has occurred in the 20th Century (the last one on 3 January 1818 involved Venus and Jupiter), although on average three events per century take place during the 2nd, 3rd and 4th millennium. Basically, the closer the conjunction, the fewer the events.
The second factor relates to the time span under review. As noted, one has to wait longer to achieve a situation of very close separation. A very high positive linear correlation between planet separation and interval between events exists and is a function of planet orbital speed. The only notable exception occurs occasionally between Mercury and Venus. For example, on 26 August 1999 and 6 Apr 2001, both planets will be more than ten degrees apart in R.A.. Yet in late October 2001, both planets will be less than one degree apart for 11 days yet never attaining true conjunction (known as quasi-conjunction.
The third and final factor involves the number of planets in conjunction at one time. By increasing the number of planets, the frequency of events will decreases sharply. For example, the interval between the time when Mercury, Venus, Mars, Jupiter and Saturn are easily visible in close proximity span from March 3, 1953 BC to September 8, 2040 AD (table 3.2).. Even the close alignment of four bright planets are quite rare (from June 1564 to Feb 2378).
Table 3.2: Grand Planetary Conjunction of 2040 A.D.
Year Date UT Mag. Mag. Sep2040 Aug 18 01:49 1.7 Mar-Jup -1.7 35' Aug 31 01:31 1.7 Mar-Sat 0.9 110' Sep 01 17:39 -3.9 Ven-Jup -1.7 10' Sep 06 17:56 -3.9 Ven-Sat 0.9 88' Sep 07 21:03 -0.2 Mer-Jup -1.7 88' Sep 11 12:09 -0.1 Mer-Sat 0.9 185' Sep 13 04:04 -3.9 Ven-Mar 1.7 13' Sep 20 15:43 -0.0 Mer-Mar 1.6 139'Table 3.2 shows the conjunction pairs associated with the Grand Conjunction of 2040. Although this event occurs over a one month period, only around September 6-8 will the planets be most favorably aligned.
Any equilateral triangle will yield a ratio of circumscribed to inscribed radii of 2:1. Equilateral right triangles yield a ratio of 2.4:1. This ratio will increase as the ratio of the sides forming the right angle increases (i.e., 2:1 side ratio results in a 2.5:1 circumscribed to inscribed ratio. At 3:1, the radii ratio is 2.8:1; 4:1, the radii ratio is 2.9:1 and 10:1, the radii ratio is 3.9:1, at 25:1 the radii ratio is 5.7:1 and 33:1, the radii ratio is 6.4:1.
Although not directly visible from Earth, all the planets except Pluto are found in the same heliocentric quadrant (<= 90 degree sector) 25 times during the first 30 centuries of the Christian era. While the inferior planets are near conjunction with the sun, the superior planets are near opposition.
Table 3.3: Exceptionally Favorable Dual Planetary Occultations (1-4000 A.D.) DATE UT PLANETS SL% REGION 35 Apr. 6 4h Jup-Sat 74+ Central/South America 629 Apr. 14 20 Jup-Nep 92+ S. Atlantic Ocean 662 Jul. 31 0 Mars-Nep 69+ S. Atlantic Ocean 1030 Jul. 7 6 Ven-Mars 14+ Antarctic 1164 Jun. 7 4 Sat-Nep 100 Antarctic 1374 Oct. 30 3 Jup-Ura 40- N. Africa 1375 Jan. 19 21 Jup-Ura 97- S. Indian Ocean 1580 Jul. 26 12 Sat-Ura 100 Mid Pacific Ocean 1683 Feb. 11 5 Jup-Sat 100 South America 1998 Apr. 23 5 Ven-Jup 15- Africa, India 2000 Mar. 4 xx Ven-Ura xx S. Indian Ocean, New Zealand 2038 Feb. 16 20 Jup-Ura 90+ Central Africa 2038 Mar. 16 5 Jup-Ura 71+ Central/South America 2444 Apr. 30 6 Jup-Nep 97+ North America (north of 35N) 2509 Jan. 24 19 Ura-Nep 11+ S. Africa 3073 May 15 4 Mars-Ura 98- Mid North Atlantic 3262 Apr. 25 1 Jup-Nep 98+ S. Atlantic OceanTable 3.3 lists all occasions during 4000 years when two planets (excluding Mercury and Pluto) are occulted by the moon at the same time. Dates prior to 1582 are on the Julian calendar; the latter are Gregorian. Each line gives the approximate Universal time when both planets are invisible due to occultation. Sunlit percent (SL%) indicates (-) for waning and (+) for waxing lunar phases. Regional visibility pertains to locale where both planets are behind the moon. Occultation of one or both planets are generally visible up to 30 degrees in longitude and 15 degrees in latitude from occultation mid-point provided that the occultation is central to the moon's diameter. Most of these events occur in night (dark) skies for part of their track.
As the moon moves from conjunction to opposition with the sun (new to full moon), planets that are occulted by the moon will also increase in brightness by the ever increasing lunar phase (as they also approach opposition). While Jupiter and Saturn increases less than 0.75 magnitude, Mars dramatically brightens more than 3.5 magnitudes. For plotting purposes, brightest magnitudes are positive (negative or a negative). At new moon, Jupiter is 3.4 magnitudes brighter than Mars. At full moon, planet magnitudes can vary as follows: Mars +/- 0.8; Jupiter +/- 0.2, Saturn +/- 0.7 from average.
Comparing planetary occultations during total lunar eclipses., the search yielded some unexpected results. Only about 5% of all occultations are easily visible (in dark skies) from a given location. The average duration of a full moon is about 30 hours, so one would expect a little more than 4% of planetary occultations to occur during this lunar phase. However, Mars with its 25-27 month period between oppositions, will encounter a full moon only 42% of the time as compared to Saturn.
Between the years 1-3000, about 5% of Mars', 10% Saturn's and 15% of Jupiter's full moon encounters occur within 15 hours of mid-totality. No same day events occurred for Mars during 1000-2000 or will for Jupiter during 2000-3000; although six minor partial eclipses with Jupiter occur (three between the years 2059-2093 and three between 2932-2990). Saturn will experience 22 same day partial eclipses while Mars will have only three during the third millennium. The 99% eclipse with Saturn in 2612 is the only significant partial eclipse conjunction in the "near" future. See supplemental Table 3.1S
On average, about one third of these full moon encounters occur within four hours of mid-totality. Distribution of these nearer time encounters vary greatly. The first millennium had 25 occurrences, six of which were occulted during totality, while this millennium had only ten (one during totality). The next 1,000 years will not include any events with Jupiter and will be limited to eight-four hours or less alignments (three during totality). Between 3000-3999, there will be no occultations during totality for Mars and Saturn (two of Saturn's encounters will occur within four hours of mid-totality). Jupiter on the other hand will have two-four hour or less alignments (both resulting in totality-occultation). See Table 3.4.
Although lunar totality is visible over more than half the Earth, the limitations of witnessing a bright planet occulted by an eclipsed moon include: (1) not all occultations go through the central axis of the moon where the maximum path width would be about 2,100 miles (the moon's diameter); and (2) although the worldwide duration of an occultation can last up to 4.5 hours (about one hour at a given location), examples in this study are solely dependent on the duration of totality which is considerably shorter (0 to 106 minutes).
While there are several dozen examples when a bright planet is near a total or partial eclipse over the millennia, the rarity of seeing a planet occulted during totality is one of astronomy's rarest predictable events unless see two planets disappear behind the moon at the same time is considered. The dual occultations in 1998 and 2038 will be our only opportunity for generations to come. For those who cannot wait, at least in today's world, we can imagine what these sights would look like through our virtual reality PC's.
Table 3.4: Bright Planetary Occultations During Totality (1-4000 A.D.)Occultation Mid-Point Totality Moon at ZenithYear Date UT Lat/Long UT Lat/Long Mag. Planet Description*400 Dec. 17 21h -5/49E 19h 23/73E 1.03 Jupiter (-2.7) SE Hemisphere*412 Nov. 4 22 -44/44E 21 16/48E 1.59 Mars (-1.9) SE Hemi (next in 2076 yrs.) *502 Dec. 29 13 28/164E 15 23/135E 1.63 Saturn(-0.5) N Pacific (next in 1078 yrs.)*524 May 3 20 -70/87W 19 -17/81E 1.63 Jupiter(-2.6) Conjunction (<15' east)*755 Nov. 23 21 54/ 29E 19 21/75E 1.38 Jupiter(-2.8) Arctic*810 Jun. 20 21 -21/45E 20 -24/61E 1.82 Jupiter(-2.8) Antarctic*879 Apr. 10 12 -72/65E 11 -9/168W 1.34 Jupiter(-2.5) Antarctic (next in 2705 yrs.)*1580 Jul. 26 12 32/159E 11 -17/165W 1.24 Saturn(0.2) Central Pacific (Uranus)2076 Jun. 17 2 -67/164E 3 20/146W 1.76 Saturn(-0.1) Antarctic (3' north)*2344 Jul. 26 12 17/166E 12 -19/175E 1.31 Saturn(0.1) Southern US2412 Nov. 18 1 65/150W 0 19/3W 1.39 Saturn(-0.4) Conjunction (2 Degs.)*2488 Apr. 26 8 -63/116E9 -14/138W 1.36 Mars(-1.6) Antarctic2612 Sep. 2 10 70/144E 10 8/144W 0.99 Saturn(0.5) 15' from partial eclipse2821 Jun. 7 2 63/3E 1 23/10W 1.72 Mars(-2.1) Atlantic Ocean Rim (67' south)2829 Jan. 11 7 34/105W 4 22/51W 1.78 Saturn(-0.4) N. America (just after totality)*2977 Jan. 26 8 17/115W 9 19/129W 1.17 Saturn(-0.3) Central-S. America3584 Jun. 6 16 -69/ 99E14 -22/148W 1.14 Jupiter(-2.5) SW Indian Ocean3881 Jun. 25 10 -60/162W10 -23/143W 1.79 Jupiter(-2.6) SE Indian OceanTable 3.4 lists all occasions during 4000 years when Mars, Jupiter and Saturn are occulted by a total lunar eclipse. Several of the best conjunctions are included as well (italic). Dates prior to 1582 are on the Julian calendar; the latter are Gregorian. Each line gives the approximate Universal time of central occultation (minimum separation) and mid-totality. Magnitude phase of lunar eclipse shows total eclipses greater than 1.0. Magnitudes follow planets. Description highlight regional visibility or circumstance of events. During the 1580 eclipse, Uranus reappears 13 minutes before Saturn disappears, all during totality! Note that a close conjunction of planet and partial eclipsed moon will still be visible over more than half the Earth during most events. Jean Meeus' work on occultations of Bright Planets by the Eclipsed Moon for the period -100 to +3000 revealed additional umbral occultations during totality: 799 Jul 21 and 1418 Oct 14 for Jupiter; 195 Jul 10, and 1591 Dec 30 for Saturn. * denote similar findings, except for the 524 AD event which occurred during totality. Jean Meeus' list also includes several occultations before or after actual totality and during partial eclipses.
Table 3.5: Uranus-Neptune Occultations During Totality (2000-4000 A.D.)Occultation Mid-Point Totality Moon at ZenithYear Date UT Lat/Long UT Lat/Long Mag. Planet Description2014 Oct. 8 10h 72/101E 11h 6/167W 1.15 Uranus(5.7) North Pole (5 Degs. abv hor)2022 Nov. 8 13 58/134E 11 17/169W 1.34 Uranus(5.6) Far East2568 Jan. 15 23 65/165E 0 21/5E 1.30 Neptune(7.8) Eastern Russia2676 Sep. 14 5 17/92W 7 -4/103W 1.01 Neptune(7.8) Mid-North Atlantic Ocean2745 Jul. 6 0 6/13E 0 -23/2E 1.48 Uranus(5.5) Middle East2919 Mar. 7 19 -30/52E 20 5/62E 1.70 Neptune(7.9) South Indian Ocean3263 Sep. 10 1 19/17W 0 -5/13E 1.28 Uranus(5.7) Mid-Atlantic Ocean3487 Aug. 26 15 -5/134E 16 -10/116E1.53 Neptune(7.8) India, SE Asia3613 Nov. 10 18 64/68E 16 18/112E 1.22 Uranus(5.7) Europe, Scandinavia3697 Nov. 11 21 574E 21 18/33E 1.35 Uranus(5.7) Europe, ScandinaviaTable 3.5 lists all occasions, during the next 2000 years when Uranus and Neptune are occulted by a total lunar eclipse. Each line gives the approximate Universal time of central occultation (minimum separation) and mid-totality. Magnitudes follow planets. Description highlight regional visibility. Note that a close conjunction of planet and partial eclipsed moon will still be visible over more than half the Earth during most events. All events were simulated with Dance of the Planets software.
Table 3.6: Bright Planet Occultations by the Sun (2000-2099 A.D.)MERCURY MARS VENUS JUPITER SATURN2000, 2046, 2092 2023 2000 2007 20042002, 2048, 2094 2038 2008 2013 20202006 2045 2016 2019 20342007, 2053, 2099 2070 2024 2025 20502009, 2055 2077 2032 2032 20632013, 2059 2040 2037 20792015, 2061 2048 2044 20932020, 2066 20492022, 2068 2081 20562026, 2072 2089 20612033, 2079 2097 20682035, 2081 20732039, 2085 2040, 2086 2090 2096Table 3.6 list the occasions when the brightest planets are occulted by the sun. Note the periodicity of: Mercury=46 years (occurring in May or Nov.), Venus=8 years (mid May-mid Jun.. & mid Nov. - mid Dec.), Jupiter=5.5 years (mid JUN-mid Jul. & mid Dec.-mid Jan.), and Saturn=14 years (Jan. or Jul.) on average. Each series eventually ends only to resume again years later. Mars had nine events in the 20th century without an obvious return cycle (May or Nov). The inferior planets exhibit repeated positions in the sky (similar to the sun-moon Saros cycle) while the superior planets' occultations occur by their repeated crossing of the sun's orbital plane (twice during the planet's orbital "year" around the sun).
Mercury and Venus occultation by the sun is sometimes known as an anti-transit. Just how rare is a transit or occultation of a planet during solar totality? For Mercury, a transit occurs just two days after an total eclipse in 2450 and 2496 while Venus will be occulted by the sun three days after an eclipse in 2291 (table 3.7). The solar conjunctions of Mercury in 2013 and 2059 (46 calendar years apart) will also include Saturn (nearby). The last event (involving Venus) occurred in 1966 and was popularized in a High Altitude Observatory/NCAR radial density filter photograph of the solar corona
Table 3.7: Bright Planet Conjunctions During Solar Totality
LOCATION TOTALITY MAXIMUMDATE SUN PLANET MAG. ECLIPSE REMARKS1966 Nov. 12 15h09m -17d41m V 15h14m -17d21m -3.9 sup-36.2/47.4W Venus 77' separation2013 Nov. 1 14h35m -15d13m M 14h20m -13d56m 4.9 inf -40.3/160.1W Saturn 14h48m -13d59m2059 May 13 3h15m +18d21m M 3h09m +17d30m -2.1 sup-11.6/101.3W Saturn 3h23m +16d32m2139 Jan. 30 20h50m -17d41m S 20h45m -18d35m 0.6 -40.2/21.9E Saturn 32' conj Jan 282150 Jun. 25 6h15m +23d22m S 6h07m +22d31m -0.1 18.2/177.5E Saturn 54' conj Jun 222179 Nov. 28 16h18m -21d22m M 16h21m -22d11m -1.3 sup-16.4/105.5W Mercury 33' conj Nov 272218 Apr. 25 2h12m +13d17m M 2h10m +12d30m -2.2 sup49.9/171.3E Mars 2h04m +12d12m2240 Aug. 18 9h53m +12d52m J 9h50m +13d54m -1.7 -13.5/30.9W Jupiter 43' conj Aug 172263 Jun. 6 4h59m +22d40m V 4h58m +23d06m -3.7 inf53.6/175.7W Venus 28' conj Jun. 62273 May 17 3h39m +19d27m J 3h43m +18d52m -2.0 22.6/29.0W Jupiter 46' conj May 182291 May 28 4h23m +21d32m V 4h20m +21d04m -3.9 sup28.3/143.8W Venus 13'* occult Jun. 12292 May 17 3h40m +19d32m M 3h33m +18d18m 5.6 inf -18.7/29.6W Mercury 26' conj May 162306 Feb. 14 21h48m -13d16m J 21h47m -14d07m -2.0 -11.3/60.9E Jupiter 42' conj Feb 132374 Dec. 4 16h42m -22d11m J 16h46m -21d45m -1.7 -13.9/42.6W Jupiter 33' conj Dec. 52377 Apr. 9 1h11m +7d32m M 1h13m +6d47m -2.1 sup-37.8/159.9E Mercury 59' conj Apr. 82382 Jul. 12 7h26m +21d56m V 7h23m +22d41m -3.9 sup5.8/128.9E Venus 45' conj Jul 142429 Dec. 26 18h21m -23d18m S 18h11m -22d24m 0.4 -53.8/47.4E Saturn 57' conj Dec 232450 May 12 3h18m +18d11m M 3h34m +19d54m 5.0 inf 6.0/152.7E Mercury 5'* transit May 14.2459 Jun. 1 4h39m +22d04m M 4h22m+21d28m -1.9 sup-67.6/45.0E Mercury 34' conj Jun. 42496 May 13 3h26m +18d42m M 3h37m +19d41m 5.4 inf 81.8/73.1W Mercury 8'* transit May 152587 Dec. 20 17h55m -23d21m V 17h49m -22d10m -3.9 inf-45.7/111.3W Venus 57' conj Dec 19Table 3.7 list all occurrences when a bright planet Mercury=M, Venus=V, Jupiter=J, and Saturn=S, are within three days of <=60' conjunction with a total solar eclipse. Inf and sup for Mercury and Venus indicate inferior and superior type of conjunctions. For the period 2000-2500 A.D., Mercury has 826 solar conjunctions <=60', Venus 212 events, Jupiter: 350 events, and Saturn 149 events. During this period, no events occur for Mars. Note the transits in 2450 and 2496 (46 years) just miss being eclipsed as well. In 1966 denotes event was not a true conjunction.
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