Sun, Mercury and Venus: Which Aspects Are Actually Possible?

← Back to Aspects

Short answer: in a single birth chart, Mercury can only be conjunct the Sun, Venus can only be conjunct the Sun, and Mercury and Venus can be conjunct or sextile each other. That's the full list. There is no natal Sun square Mercury, no Sun opposite Venus and no Mercury trine Venus, and the reason is astronomy rather than astrological taste.

If you have seen "Sun square Venus" in an app or a horoscope column, it was describing something other than one natal chart: the Sun moving through the sky today against your natal Venus, for example, or a comparison between two people's charts.

The three pairs at a glance

We found those maximums by checking the chart for noon on every day from 1 January 1900 to 31 December 2099 (73,049 charts) with the same planetary routines that power the free birth chart. The peaks fell on 31 March 1967 for Mercury, 21 December 2088 for Venus and 14 March 2060 for the Mercury-Venus pair. A daily check can miss the true peak by a few hundredths of a degree, which changes nothing below.

Why Mercury and Venus stay near the Sun

Both planets orbit the Sun inside Earth's orbit. From where we stand, that means they can never appear on the far side of the sky from the Sun. They swing out to one side, turn, cross in front of or behind the Sun, and swing out to the other side. Astronomers call the widest point of each swing the greatest elongation.

Venus has the larger orbit of the two, so its swing is wider: up to about 47°. Mercury's orbit is small and quite eccentric, so its widest swing varies from one cycle to the next and never reaches much past 28°. This is why Venus is sometimes a bright evening star for months, while Mercury is a brief, low sighting near twilight. The same leash shapes Venus's aspects to slow bodies: Venus opposite Chiron, for example, can only happen while Chiron is retrograde.

The orb arithmetic

The calculator uses five major aspects with flat orbs, the same for every pair of points:

• Conjunction: 0° to 8°
• Sextile: 54° to 66°
• Square: 82° to 98°
• Trine: 112° to 128°
• Opposition: 172° to 180° (separations are measured the short way round, so 180° is the most two points can be apart)

Now line those ranges up against the table. The Sun and Mercury never get past 28°, which is nowhere near the 54° a sextile needs. The Sun and Venus stop at about 47°, still short of 54°. Mercury and Venus can reach about 74° because they can sit on opposite sides of the Sun, one in the morning sky and one in the evening. That clears the sextile range but stops well short of the 82° a square would need.

Everything else on the grid, from Sun sextile Venus to Mercury opposite Venus, simply has no matching sky.

How often the possible ones turn up

Across the same 73,049 daily charts:

Roughly one chart in four has Mercury within 8° of the Sun. That makes Sun conjunct Mercury one of the most common aspects anyone can have, and it's worth reading it in proportion: it describes a real emphasis, but it's not a rare signature.

Worked example

Take a birth at noon in London on 10 May 1999. The planet table shows the Sun at 19°21' Taurus, Mercury at 2°49' Taurus and Venus at 1°58' Cancer.

• Sun to Mercury: about 16.5°. Too wide for a conjunction, so no aspect.
• Sun to Venus: about 42.6°. No major aspect exists in that range.
• Mercury to Venus: about 59.2°. A sextile, less than 1° from exact.

Mercury trails behind the Sun and Venus runs ahead of it, which is exactly the arrangement every Mercury-Venus sextile needs. On the wheel you would see a blue dashed line between ☿ and ♀, and no line from either of them to ☉.

When there is no aspect at all

Most charts have no aspect in at least one of these pairs. That still tells you something. Mercury is always in the Sun's sign or a neighbouring one, and Venus is never more than two signs from the Sun, so their sign styles are close relatives of your Sun sign even without an aspect. Read them through their signs and houses as you would any planet. The pages on Mercury signs and Venus signs are the place to start.

No aspect between one of these pairs does not mean that either planet is unaspected. Mercury, Venus and the Sun can each still make major aspects to the Moon, Mars, the slower planets, the Lunar Nodes and Chiron. A planet is only called unaspected when it has no major aspect to any of those partners; unaspected planets sets out the test and how to check whether a planet is unaspected shows how to apply it.

Some astrologers also use minor aspects for these pairs. Venus can reach the semi-sextile (30°) and the semi-square (45°), for instance. The standard calculator does not detect minor aspects, so they won't appear on your chart; the minor aspects guide covers them as an optional extra layer.

Retrograde and the Sun

Mercury and Venus turn retrograde around the time they pass between Earth and the Sun. So every retrograde period of either planet falls around one of its conjunctions with the Sun, the one on the near side. On the days Mercury was conjunct the Sun in our sample, it was retrograde 31.2% of the time; for Venus the figure was 14.0%. The pages on Mercury retrograde and Venus retrograde in the natal chart explain what the R marker means.

The pages in this set

• Sun conjunct Mercury: thinking and identity running close together
• Sun conjunct Venus: values and affection near the core self
• Mercury conjunct Venus: words with a feel for harmony
• Mercury sextile Venus: the widest aspect these two can make
• Moon sextile Venus and Moon opposite Venus, which complete the Moon-Venus set

For the general rules behind all of this, see aspect orbs and the major aspects. The methodology page lists exactly which aspects and orbs the calculator uses.

Check your own chart

Open your free birth chart and look at the planet table under the wheel. Note the degree and sign of ☉, ☿ and ♀, count the degrees between them (remembering that each sign is 30°), and compare the result with the ranges above. Conjunction lines between close planets are short and easy to miss on the wheel, so the numbers are the more reliable check. If you'd like help weighing what you find, Ask the Astrologist.