Book contents
- Frontmatter
- PREFACE
- Contents
- ILLUSTRATIONS
- CHAPTER I THE TELESCOPE, ITS INVENTION AND THE DEVELOPMENT OF ITS POWERS
- CHAPTER II RELATIVE MERITS OF LARGE AND SMALL TELESCOPES
- CHAPTER III NOTES ON TELESCOPES AND THEIR ACCESSORIES
- CHAPTER IV NOTES ON TELESCOPIC WORK
- CHAPTER V THE SUN
- CHAPTER VI THE MOON
- CHAPTER VII MERCURY
- CHAPTER VIII VENUS
- CHAPTER IX MARS
- CHAPTER X THE PLANETOIDS
- CHAPTER XI JUPITER
- CHAPTER XII SATURN
- CHAPTER XIII URANUS AND NEPTUNE
- CHAPTER XIV COMETS AND COMET-SEEKING
- CHAPTER XV METEORS AND METEORIC OBSERVATIONS
- CHAPTER XVI THE STARS
- CHAPTER XVII NEBULÆ AND CLUSTERS OF STARS
- NOTES AND ADDITIONS
- INDEX
- Plate section
CHAPTER III - NOTES ON TELESCOPES AND THEIR ACCESSORIES
Published online by Cambridge University Press: 05 July 2011
- Frontmatter
- PREFACE
- Contents
- ILLUSTRATIONS
- CHAPTER I THE TELESCOPE, ITS INVENTION AND THE DEVELOPMENT OF ITS POWERS
- CHAPTER II RELATIVE MERITS OF LARGE AND SMALL TELESCOPES
- CHAPTER III NOTES ON TELESCOPES AND THEIR ACCESSORIES
- CHAPTER IV NOTES ON TELESCOPIC WORK
- CHAPTER V THE SUN
- CHAPTER VI THE MOON
- CHAPTER VII MERCURY
- CHAPTER VIII VENUS
- CHAPTER IX MARS
- CHAPTER X THE PLANETOIDS
- CHAPTER XI JUPITER
- CHAPTER XII SATURN
- CHAPTER XIII URANUS AND NEPTUNE
- CHAPTER XIV COMETS AND COMET-SEEKING
- CHAPTER XV METEORS AND METEORIC OBSERVATIONS
- CHAPTER XVI THE STARS
- CHAPTER XVII NEBULÆ AND CLUSTERS OF STARS
- NOTES AND ADDITIONS
- INDEX
- Plate section
Summary
Choice of Telescopes.—The subject of the choice of telescopes has exercised every astronomer more or less, and the question as to the best form of instrument is one which has occasioned endless controversy. The decision is an important one to amateurs, who at the outset of their observing careers require the most efficient instruments obtainable at reasonable cost. It is useless applying to scientific friends who, influenced by different tastes, will give an amount of contradictory advice that will be very perplexing. Some invariably recommend a small refractor and unjustly disparage reflectors, as not only unfitted for very delicate work, but as constantly needing re-adjustment and resilvering.
Others will advise a moderate-sized reflector as affording wonderfully fine views of the Moon and planets. The question of cost is greatly in favour of the latter construction, and, all things considered, it may claim an unquestionable advantage. A man who has decided to spend a small sum for the purpose not merely of gratifying his curiosity but of doing really serviceable work, must adopt the reflector, because refractors of, say, 5 inches and upwards are far too costly, and become enormously expensive as the diameter increases. This is not the case with reflectors; they come within the reach of all, and may indeed be constructed by the observer himself with a little patience and ingenuity.
Refractors and Reflectors.—The relative merits of refractors and reflectors have been so frequently compared and discussed that we have no desire to re-open the question here.
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- Telescopic Work for Starlight Evenings , pp. 38 - 65Publisher: Cambridge University PressPrint publication year: 2010First published in: 1891