ASTRO II Constellation Watch - An astronomical watch with a manually rotated planisphere / constellation disc. 42mm case size. Constellation display of the entire sky at 35 deg. North Latitude / North Hemisphere. The ASTRO watch is perfect for anyone interested in Space, Science, Astronomy and the night sky. This quartz analog watch displays a wealth of data - Current time, Current positions of the constellations (set the planisphere disc via the crown at 3-o-clock), once disc is correctly set you can read azimuth and altitude of the major fixed stars, nebulae and star clusters, local sidereal time, stellar spectral type, pole star hour angle, hours for astronomical twilight and other functions for astronomical observing. Most of the celestial sphere (approx. 98.6%) visible at 35deg. north latitude is displayed. The range shown on the constellation dial: –55.57deg. to +77.06deg. declination. The constellation display includes the positions of 1,056 fixed stars with a brightness of 4.8 magnitude or brighter, 169 major nebulae and star clusters, delimitation of constellations, ecliptic and celestial equator. The position of the sun is shown in a broken line along the ecliptic (the sun's apparent path on the celestial sphere during the year) on the 1st, 11th, and 21st of each month (for 12:00 noon Universal Time over the mean year). Times for sunrise and sunset as well as the number of daylight hours can be determined by examining the horizon line on the crystal underprint. Local sidereal time can be designated by reading the right ascension graduations on the constellation dial that intersect with the meridian on the transparent dial. The hour angle display of the pole star lets you align an astronomical telescope to the polar axis. Quality components and construction: 100% Japan quartz movement (made by Citizen), 42mm 316L stainless steel case, 20mm black silicone rubber strap, 3 ATM water resistance.