Ophiuchus perpetuates the memory of Æsculapius, father of medicine. He and his serpent, as seen in the sky, are exceedingly hard to trace but men also sought to do him honor on earth by erecting temples in which he was worshiped. The brightest star in the constellation of Ophiuchus, the Serpent Bearer, is Ras Alhague, although this name has gone entirely out of use and the star is generally designated as α Ophiuchi. [Figure 62] This star lies on the head of Ophiuchus which is about three-quarters of the way up from the horizon to the zenith, when on the meridian. It rises a little north of east, appearing When the sun sets on the 14th of May, and requiring 6 hours and 46 minutes to reach the line midway between east and west. Ras Algethi (α Herculis), a beautiful orange colored star on the head of Hercules, is usually noted in connection with Ras Alhague, since they stand rather isolated only about 6 degrees apart. (The distance between the "Pointers" on the outer side of the Big Dipper is equal to 5 degrees.) When Ras Algethi and Ras Alhague are near the meridian, a glance of the eye beyond will meet two stars of the 2nd magnitude also not far apart. These are "The Dragon's Eyes," Alwaid and Etanin. Recalling that Hercules has his foot on the Dragon's head, that the head stars of the two giants' lie almost together, and the feet of the lower giant, Ophiuchus, are crushing down Scorpio, the Scorpion (a conspicuous anchor shaped constellation in the south), one has a fairly good idea of this section of the sky from the Pole Star to the horizon, when Ras Alhague and Ras Algethi are near the meridian. Since both Hercules and Ophiuchus have very large but also very inconspicuous constellations, it is well to keep them connected in some such manner. In modern days the constellation of Hercules has gained in interest through observations made by the telescope. Unfortunately the ancients were not privileged to see its gayly colored double stars and its marvelously beautiful star cluster. [Figure 63] Among the double stars, Young mentions an orange and blue, and a white and emerald green; the Rev. T. W. Webb points out one almost appetizingly attractive in its light apple green and cherry red while Serviss notes some charming combinations--orange and green, pale green and purple, light yellow and pale red--which may be seen with such meager assistance as an opera-glass. Serviss, by the way, has written a whole book on what may be seen in the sky with no greater aid than an opera-glass.