Fixed star:  ACUMEN
Constellation:  M7 Scorpius
Longitude 1900:  27SAG21. Longitude 2000:  28SAG45.
Declination 1900:  -34.47'. Declination 2000:  -34.49'.
Right ascension:  17h53m. Latitude:  -11.22'.
Spectral class:  C. Magnitude:  3.2.

History of the star: A star in the sting of the Scorpion Scorpius. A companion cluster to Aculeus and of the same nature.

The Akkadians called Scorpio, Girtab, the "Seizer", or "Stinger", and the Place where One Bows Down, titles indicative of the creature's dangerous character; and referring to the striking curve of stars which lies in a dark portion of the Milky Way that forms the tail of the Scorpion, terminating in the poisonous upturned stinger, as if ready for an attack. [Star Names, Their Lore and Meaning, Richard Hinchley Allen, 1889].

Etymology: Isaac Mozeson author of "The Word", says about Acumen: "It means sting in Latin, smarts in English. [K]HaKHMaH means smart in Hebrew. Either way, it smarts (hurts). Beyond other things said about the sting root in Indo-European and Edenic, QaM means an enemy, or literally one who rises up against you".
In "The Word" Isaac Mozeson says about the word Acumen: "ACUMEN is a Latin word meaning mental acute-ness as well as a point and a sting. The IE root is ak, signifying sharpness. Hebrew HAKH'MA means intelligence and skill, a word of mental acuity with many sharp branches.

BRANCHES: To sting is Hebrew OKUTZ or HEKESH. HOAKH is a briar or thorn, while English COG is a tooth. HAKU is a fishhook and HAKA is to angle (for fish) or to wait. The KM element of HAKHMA recalls the objects of wisdom: the KUMA (how much), the KIMO (in common) and the KAMOOS (hidden, concealed). Psalms 111:10: At the head of wisdom is awe for God. " [The Word, dictionary, Isaac Mozeson, Edenic (Biblical Hebrew), SPI books, ISBN 15671-942-0]. 

The astrological influences of the constellation: The Scorpion is associated with the Hebrew letter Oin and the 16th Tarot Trump "The Lightning-Struck Tower". (Robson*).

The astrological influences of the constellation given by Manilius:

"The Scorpion presides over arms" [Manilius, Astronomica, 1st century AD, book 4, p.253]

By virtue of his tail armed with its powerful sting, wherewith, when conducting the Sun's chariot through his sign, he cleaves the soil and sows seed in the furrow, the Scorpion creates natures ardent for war and active service, and a spirit which rejoices in plenteous bloodshed and in carnage more than in plunder. Why, these men spend even peace under arms : they fill the glades and scour the woods; they wage fierce warfare now against man, now against beast, and now they sell their persons to provide the spectacle of death and to perish in the arena, when, warfare in abeyance, they each find themselves foes to attack. There are those, too, who enjoy mock-fights and jousts in arms (such is their love of fighting) and devote their leisure to the study of war and every pursuit which arises from the art of war. [Manilius, Astronomica, 1st century AD, p.239-240].

The general astrological influences of the star: It effects the eyesight and causes blindness of one or both eyes, if in conjunction with an afflicted luminary or in conjunction with a malefic that afflicts the luminaries. The opposition seems to be equally important. (Robson*).  

This star along with Aculeus has a notorious reputation in astrology as 'blind stars' or stars associated with eyesight problems. These stars shows up a negative Mars-Moon quality in people who have them poorly aspected, with a tendency towards a morbid outlook, seeing the worst rather than the best in everything. If their religious views are affected, as so often with anything in Sagittarius, there is a tendency to be either the 'hellfire and damnation brigade' or to take up a fierce anti-religious and even anti-God stance. But at their best, well aspected, they can have very sharp minds and a perception well above average as though, perhaps 'blind' to what we see and take for granted, they see what we do not, at levels where eyesight does not reach. Not for nothing has the word Acumen come down to us as a term for a sharp mind. (The Living Stars, Dr. Eric Morse).

References

 *(Fixed Stars and Constellations in Astrology , Vivian E. Robson, 1923)