Book contents
- Frontmatter
- PREFACE
- SUPPLEMENT
- Contents
- LIST OF ILLUSTRATIONS
- PRINCIPAL AUTHORITIES
- Errata
- A Handbook of Descriptive and Practical Astronomy
- BOOK I A SKETCH OF THE SOLAR SYSTEM
- BOOK II ECLIPSES AND THEIR ASSOCIATED PHENOMENA
- CHAPTER I GENERAL OUTLINES
- CHAPTER II ECLIPSES OF THE SUN
- CHAPTER III THE TOTAL ECLIPSE OF THE SUN OF JULY 28, 1851
- CHAPTER IV THE ANNULAR ECLIPSE OF THE SUN OF MARCH 14–15. 1858
- CHAPTER V THE TOTAL ECLIPSE OF THE SUN OF JULY 18, 1860
- CHAPTER VI HISTORICAL NOTICES
- CHAPTER VII ECLIPSES OF THE MOON
- CHAPTER VIII SUGGESTIONS FOR OBSERVING ANNULAR ECLIPSES OF THE SUN
- CHAPTER IX TRANSITS OF THE INFERIOR PLANETS
- BOOK III THE TIDES
- BOOK IV MISCELLANEOUS ASTRONOMICAL PHENOMENA
- BOOK V COMETS
- BOOK VI CHRONOLOGICAL ASTRONOMY
- BOOK VII THE STARRY HEAVENS
- CHAPTER I
- Chapter II DOUBLE STARS, ETC.
- CHAPTER III
- CHAPTER IV CLUSTERS AND NEBULÆ
- CHAPTER V THE MILKY WAY
- CHAPTER VI THE CONSTELLATIONS
- BOOK VIII ASTRONOMICAL INSTRUMENTS
- BOOK IX A SKETCH OF THE HISTORY OF ASTRONOMY
- BOOK X METEORIC ASTRONOMY
- APPENDICES
- INDEX TO SUBJECTS
- INDEX TO NAMES
- Plate section
- Frontmatter
- PREFACE
- SUPPLEMENT
- Contents
- LIST OF ILLUSTRATIONS
- PRINCIPAL AUTHORITIES
- Errata
- A Handbook of Descriptive and Practical Astronomy
- BOOK I A SKETCH OF THE SOLAR SYSTEM
- BOOK II ECLIPSES AND THEIR ASSOCIATED PHENOMENA
- CHAPTER I GENERAL OUTLINES
- CHAPTER II ECLIPSES OF THE SUN
- CHAPTER III THE TOTAL ECLIPSE OF THE SUN OF JULY 28, 1851
- CHAPTER IV THE ANNULAR ECLIPSE OF THE SUN OF MARCH 14–15. 1858
- CHAPTER V THE TOTAL ECLIPSE OF THE SUN OF JULY 18, 1860
- CHAPTER VI HISTORICAL NOTICES
- CHAPTER VII ECLIPSES OF THE MOON
- CHAPTER VIII SUGGESTIONS FOR OBSERVING ANNULAR ECLIPSES OF THE SUN
- CHAPTER IX TRANSITS OF THE INFERIOR PLANETS
- BOOK III THE TIDES
- BOOK IV MISCELLANEOUS ASTRONOMICAL PHENOMENA
- BOOK V COMETS
- BOOK VI CHRONOLOGICAL ASTRONOMY
- BOOK VII THE STARRY HEAVENS
- CHAPTER I
- Chapter II DOUBLE STARS, ETC.
- CHAPTER III
- CHAPTER IV CLUSTERS AND NEBULÆ
- CHAPTER V THE MILKY WAY
- CHAPTER VI THE CONSTELLATIONS
- BOOK VIII ASTRONOMICAL INSTRUMENTS
- BOOK IX A SKETCH OF THE HISTORY OF ASTRONOMY
- BOOK X METEORIC ASTRONOMY
- APPENDICES
- INDEX TO SUBJECTS
- INDEX TO NAMES
- Plate section
Summary
There are many stars which exhibit periodic changes of brilliancy quite unaccounted for by any causes with which we are acquainted; these are termed variable stars. One of the most remarkable is o Ceti (Mira), which was first observed by David Fabricius in 1596. It appears about 12 times in 11 years; remains at its greatest brightness about a fortnight, when it sometimes equals in brilliancy a star of the 2nd magnitude; decreases during about 3 months till it becomes totally invisible; it remains so for about 5 months, and then gradually recovers its brilliancy during the remaining 3 months of its period. Its maximum brightness is not always the same, nor does it always increase or diminish by the same gradations. According to Hevelius, nothing was seen of it between October, 1672, and December, 1676. Algol (β Persei) is another well-known instance of this kind. For about 2d. 13h. it shines as an ordinary star of the 2nd magnitude. In about 3½ hours it is reduced to the 4th magnitude, and thus remains about 20 minutes; it then rapidly increases to the 2nd, and continues so for another period of 2d. 23h., when similar changes recur.
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- A Handbook of Descriptive and Practical Astronomy , pp. 288 - 293Publisher: Cambridge University PressPrint publication year: 2010First published in: 1861