The Seba library treats Sol Niger in 9 passages, across 6 authors (including Jung, Carl Gustav, Jung, C. G., Jung, C.G.).
Saturn, in astrology the 'star of the sun,' is alchemically interpreted as black; it is even called 'sol niger' and has a double nature as the arcane substance, being black outside like lead, but white inside.
Jung defines Sol Niger as an alchemical name for Saturn, the arcane substance whose outward blackness conceals an inner white brilliance, establishing its double nature as foundational to the symbol.
, Aion: Researches into the Phenomenology of the Self, 1951thesis
There is, however, also a Sol niger, who, significantly enough, is contrasted with the day-time sun and clearly distinguished from it... the unconscious is not only contaminated with its own negative side but is burdened with the shadow cast off by the conscious mind.
Jung argues that Sol Niger is the shadow-burdened counterpart of ordinary solar consciousness, psychologically equivalent to the unconscious laden with what the ego has repressed.
, Mysterium Coniunctionis: An Inquiry into the Separation and Synthesis of Psychic Opposites in Alchemy, 1955thesis
With regard to your question about the black sun, Baudelaire's 'soleil noir' is by no means an exception... we find the sol niger in alchemy, also the ignis niger.
Jung situates Sol Niger within a cross-cultural symbolic family including Pythagorean counter-earth and Baudelaire's poetic black sun, affirming its archetypal rather than merely alchemical status.
, Letters Volume 2, 1951-1961, 1975thesis
With regard to your question about the black sun, Baudelaire's 'soleil noir' is by no means an exception... we find the sol niger in alchemy, also the ignis niger.
Parallel to the 1975 letter, Jung here confirms Sol Niger as a recurrent symbolic motif linking alchemical, philosophical, and literary traditions around the concept of a dark or counter-sun.
, Letters Volume 1: 1906-1950, 1973thesis
Saturn was sometimes called sol niger, the black sun. In his darkness there is to be found a precious brilliance, our essential nature, distilled by depression as perhaps the greatest gift of melancholy.
Moore identifies Sol Niger with the psychologically redemptive dimension of Saturnine depression, arguing that the black sun conceals a precious brilliance available only through descent into darkness.
, Care of the Soul Twenty-fifth Anniversary Edition: A Guide, 1992thesis
Sol Niger, 129, 166–67 Solar: animals, 134; night, 134-35; psychology, 127, 129
Moore's index entry co-locates Sol Niger with solar night and solar psychology within Ficino's astrological framework, indicating the term's structural importance in his treatment of Saturn and the shadow-sun.
, The Planets Within: The Astrological Psychology of Marsilio Ficino, 1982supporting
Sol Niger, 129, 166–67 Solar: animals, 134; night, 134-35; psychology, 127, 129
The revised edition of Moore's Ficino study preserves the same index placement, confirming Sol Niger as a sustained node in his astrological-psychological inquiry into the dark aspect of solar psychology.
, The Planets Within: The Astrological Psychology of Marsilio Ficino, 1990supporting
Like cures like; we cure the nigredo by becoming, as the texts say, blacker than black – archetypally black, and thereby no longer colored by all-too-human prejudices of color.
Hillman's prescription to become 'blacker than black' articulates the Sol Niger logic of descent into darkness as the only genuine movement beyond the nigredo rather than away from it.
, Alchemical Psychology, 2010supporting
Michael Maier used the dramatic image of throwing 'snow in Saturn's black face' in order to represent the process of whitening the blackened 'body' of the Stone, which has putrefied in the bottom of the vessel at the 'nigredo'.
Abraham's dictionary entry on snow invokes the Saturnine blackened body of the nigredo — the material correlate of Sol Niger — as the substance to be whitened in the alchemical work.
, A Dictionary of Alchemical Imagery, 1998aside