Astronomy

61 Cygni apparent motion appears atmosphere attraction axis Bear's tail bright stars called centre circles of latitude clock cloth boards constellation corresponding craters Crown 8vo density diameter direction earth's orbit eastward ellipse equator exactly Full Moon globe Greenwich Groombridge 1830 heat heavenly body heavens hemisphere horizon illustrations on toned inferior conjunction inferior planet interval Jupiter large number light longitude magnitude Mars mass Mercury meridian meteors Moon's motion moving round naked eye nearly nebulæ Neptune node northern observations opposite oval parabola parallax particles passing path PERIODICAL COMETS pole Pole-star position pull radius rays right ascension rotation round the earth round the Sun Royal 16mo Saturn seen shift side sidereal solar southern spectrum Sun's disc superior planet suppose surface tail three full-page illustrations tilt tion toned paper transit Uranus velocity Venus vernal equinox visible westward whilst zenith Zodiac zodiacal light