I think you meant to say "the memorial stone devoted to STOCKHAUSEN", but I do take your point. It has the MITTWOCH version of the formula, and text taken from that opera, and yet is engraved in Michael's blue instead of the Mittwoch colour of yellow. Perhaps it is a typographical error?
Yes, and in addition, see TEXTE V, pages 182 and 378, and TEXTE VI, pp. 199–200. The liner notes for the CD recording of SAMSTAG also gives Lucifer's primary (exoteric) and secondary (esoteric) colours, in a footnote added to the text from the programme book for the La Scala premiere. The Leipzig Opera programme book for the premiere of FREITAG gives a different version of the esoteric colours for that day (Eve and Lucifer's primary colours of light green and shiny black) than is found in earlier sources (dark green-red, whatever that might be!). The texts of WOCHENKREIS and AVE also give variant forms of the colours, including that of MONTAG: "silver-green". It is interesting that the exoteric colour for SAMSTAG was originally "night blue" (TEXTE V, p. 378), which resonates with the idea that Michael and Lucifer are "brothers" (TEXTE VI, pp. 155 and 383). The WOCHENKREIS text also gives the exoteric colour of Saturday as "Schwarz—Eisblauschwartz".
Blue - lapis lazuli - is the most expensive colour of medieval/Renaissance art and is associated with the Virgin Mary. Given KS's admiration of the symbolism of this art, perhaps we might pay some attention to the the integration of colour, role, and destiny in this period of art, even though it may upset some theories. What would Goethe say?
I know your question refers principally to the Farbenlehre, and this has little to do with colours, but there is an interesting description in the first act of Faust, Part 2, of some of the traditional alchemical attributions of the planets, in the Astrologer's first speech (lines 4955–4970):
Die Sonne selbst sie ist ein lautres Gold, Mercur der Bote dient um Gunst und Sold, Frau Venus hat’s euch allen angethan, So früh als spat blickt sie euch lieblich an; Die keusche Luna launet grillenhaft, Mars trifft er nicht, so dräut euch seine Kraft. Und Jupiter bleibt doch der schönste Schein, Saturn ist groß, dem Auge fern und klein, Ihn als Metall verehren wir nicht sehr, An Werth gering, doch im Gewichte schwer. Ja! wenn zu Sol sich Luna fein gesellt, Zum Silber Gold, dann ist es heitre Welt; Das Uebrige ist alles zu erlangen: Paläste, Gärten, Brüstlein, rothe Wangen, Das alles schafft der hochgelahrte Mann, Der das vermag was unser keiner kann.
Surely this is not entirely alien to Stockhausen's treatment of the days of the week, with their planetary associations.
Again back to the difference of exoteric and esoteric colours - I did not remember this terminology of Stockhausen's in TEXTE VI. How should we understand this use of the words? For "normally" exoteric means: that, what is at the surface, what is obvious for everybody; and esoteric is what is known just for the expert, for those people who are able to perceive the hidden source of everything. In this way the esoteric is what essentially matters. But that does not correspond to main-colours and secondary-colours.
Perhaps Stockhausen's use of the words does not conform to what they ought to mean (so many things in this imperfect world seem to be like that!). Or perhaps I have reversed Stockhausen's intentions, though it would seem odd for the familiar, very public primary colours to be regarded as "esoteric" and the unfamiliar, secondary ones "exoteric"! The relevant passage in TEXTE VI is on p. 200, about halfway down the page:
MITTWOCH ist hellgelb. DONNERSTAG is der Michaelstag, hellblau. FREITAG, die Versuchung Evas durch Luzifer, ist als Farbe orange. (Es gibt jedesmal eine esoterische und eine exoterische Farbe—so, wie MONTAG nicht nur hellgrün ist, sondern opalfarben, silberfarben, so ist DONNERSTAG nicht nur hellblau, sondern auch purpurviolett.)
For the benefit of those with limited German, this passage is somewhat freely translated by Tim Nevill on page 86 of Towards a Cosmic Music: Texts by Karlheinz Stockhausen (Element Books, 1989):
Wednesday, which is bright yellow, is – as I’ve already indicated – the conference day. Michael, Eve and Lucifer must reach agreement on their various interests. Thursday is Michael’s day, light-blue. Friday with Eve’s temptation by Lucifer is orange in colour. For every day there is both an esoteric and exoteric colour. Monday is, for instance, opal and silver as well as light green. Thursday is purple as well as light blue.
I have been consulting a German edition of William I. Thompson, Die Pazifische Herausforderung: Re-vision des politischen Denkens (Goldmann-Verlag, 1986) (orig. The Pacific Shift, 1984) a gift inscribed by Stockhausen (in red, as it happens) as a token of our last meeting on 16 December 1990. A series of colour-coded triangle patterns accompanying the author's ostensibly political analysis of the state of the universe identify the colour purple with the Cosmos, red with Chaos, cyan blue with Routine, and yellow with Charisma (yeah, right), and the Four Worlds as Communistic (Agape, Ontos, Routine), Capitalistic (Ontos, Logos, Charisma), Raw Material Rich (Charisma, Eros, Chaos) and Raw material Poor (Chaos, Thanatos, Routine). Whether this colour scheme formed part of Stockhausen's symbolism or was given me as an attempt to divert attention I cannot say for sure, and frankly do not care. My personal view is that, like the Urantia Book, such literature adds little if anything to our understanding of the music and is part of a larger element of quasi-intellectual "chaff" with which the composer surrounded himself toward the end of his life in an attempt at protection. I would include claims of originating from Sirius as part of that. It adds nothing to the music. All it tells us is that Stockhausen chose to associate himself with a strain of holistic introversion associated with early 20th century art, one which also seduced John Cage and a number of highflying German intellectuals including Werner Heisenberg and Carl Friedrich von Weizsäcker as well as a number of delusional American doomsday cults.
Of course you have nothing to know about the Urantia Book to love OKTOPHONIE or MITTWOCHS GRUSS. Even for the understanding of LICHT you don't need to know anything about it. But if you want to understand works like JERUSEM or ORVONTON in a broader sense (not only the music) it can't be that useless. By the way: There is no "doomsday cult" about the Urantia Book. Knowing the Urantia scene very well, I can tell you that there is no cult and no church. There are only lose organized study groups and readers' associations whose people would for 90 %, I guess, reject the idea of founding a cult or a church. So the Urantia Foundation does, too. And there is nothing about doomsday! When the book was presented at esoteric fairs in the last years many people walked away without any further interest - and you know why? Because the book tells nothing about the Maya agenda and the 21st December 2012! In the different Urantia groups there are remarkable many ex-Jehova's witnesses. And you know why? Because they are so happy to have found a revelation without any threatening doomsday! The Urantia Book is full of optimism and the pleasant anticipation of an eternal voyage through the universe - otherwise Stockhausen wouldn't have loved it that much.
I feel that it could be useful to have a discussion-forum on the music of Stockhausen. There are so many people from all over the world, young and old, learned and eager to get into contact with this musical world: musicologists, composers, musicians, music lovers; people who plan concerts - who write books or have to give lectures and so on. So there should be much stuff, many ideas that we can share. And when we have open questions, there may be people who studied just that and could give a hint or a stimulus.
A problem might be the English language, but i feel that is the only possibility that many people who are interested can participate. And we can exercise tolerance to mistakes!