Galilean Anagrams

Something amusing for the holidays: to assure himself of the repute of discovering two more unsuspected occurrences in the heavens following his discovery of the Medicean Stars (the four principal moons of Jupiter, now called the Galileans in his honour, the first bodies known not to orbit the earth), Galileo Galilei issued two anagrams around 1610 (a common method of the day), and later revealed their solutions as sentences announcing his discoveries.

Meanwhile, however, Johannes Kepler (not in Galileo's confidence) had attempted his own solutions, and made two incorrect correct discoveries – for his attempted unscramblings revealed two more planetary facts that were not actually discovered for decades or centuries!

Galileo's cryptograms:

(1) Haec me immatura a me iam frustra leguntur o. y.

(2) SMAISMRMILMEPOETALEUMIBUNENUGTTAUIRAS

Galileo's intended solutions:

(1) Cynthiae figuras aemulantur mater amorum.  

("The shapes of Cynthia [i.e. the Moon's phases] are imitated by the Mother of Loves [i.e. Venus: he means that, like the Moon, Venus has phases too].")

(2) Altissimum planetam tergeminum observavi.  

("The highest/furthest planet [i.e. Saturn - no further were yet known] I have observed to be 'tri-twin' [i.e. he saw Saturn as a central sphere with two companion orbs thus: oOo].")

Galileo's primitive telescopes were insufficient to reveal the rings clearly: he saw them first as unmoving companions and later as "ears" or "handles", to his bewilderment.  The mysterious appearance of Saturn baffled all observers until Huygens made the conceptual leap necessary to postulate a ring orbiting about Saturn in 1655.

Kepler's incorrect, yet prescient solutions:

(1) Macula rufa in Jove est gyratur mathem. etc.  

("There is a red spot on Jupiter which rotates mathematically.")

(2) Salve, umbistineum geminatum Martia proles.  

("Hail, twin companionship, offspring of Mars [i.e. Mars has two satellites].")

I must say, I have no idea what umbistineum means: it's not in my Latin dictionaries... apparently Kepler thought it a Latinized form of the German umbeistehn.

The Great Red Spot was first observed by Hooke in 1664, and it was not till 1877 that Hall discovered Phobos and Deimos, the moons of Mars.  (It must be said, however, that Kepler thought it entirely proper that Mars should have two satellites, since then Earth would have one, Mars two, and Jupiter four, in an arithmetical progression: the human capacity for pattern-recognition at work.)

A final question: why do we refer to Kepler by his surname, yet to Galileo by his Christian name?  Is Galilei simply too hard to pronounce comfortably in English?