Annals of the Lowell Observatory Volume 2

Annals of the Lowell Observatory Volume 2

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 edition. Excerpt: ...irradiation of the limb and the difference between the measures from the terminator will give twice the amount of its lesser irradiation. CHAPTER III. DRAWINGS AND NOTES. In the process of map-making the examination of the drawings of detail follows the study of the more exact measures of position. After the actual measures have been plotted upon the globe which is to represent another world, these drawings are used to fill in the parts unmeasured. For this purpose it is necessary to compare most carefully the drawings both with each other and with the resulting map. It was found by trial that a person not thoroughly accustomed to work on Mars at the telescope could not do this, for he judges identity by position only, instead of by general appearance and conspicuousness as well as position. Wrong position is one of the errors in free-hand drawings which will be discussed in the next chapter. The work of comparing the drawings in order to get details for the map was done by the writer, and so also was the comparing of the map with every drawing in order to find any further corrections. The lists of canals and oases in this chapter give the identification of markings obtained in this second review of the map. A study of these lists, or even the perusal of a page here and there, will give the reader a good idea of the excellent climatic conditions under which the observations were made and the ease with which most difficult objects were frequently seen. The lists give the conditions of the observations and the elements from which a judgment of their value may be obtained by one familiar with this class of work. Long lists of this kind in planeto-physical work are the equivalent of great masses of figures in astronomy of precision, and in proportion...
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Product details

  • Paperback | 124 pages
  • 189 x 246 x 7mm | 236g
  • Miami Fl, United States
  • English
  • Illustrations, black and white
  • 1236555023
  • 9781236555021