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Updated: June 9, 2025
He must have the object-glass properly adjusted in its tube, and must use the highest power; that is, the smallest eye-piece, which he intends to use in the instrument. Of course he understands that in looking directly at a star or a celestial object it must appear sharp in outline and well defined. But without long practice with good instruments, this will not give him a very definite idea.
His nerves were not perhaps as steady as they would have been without the shock which he had already received, and he shrank back from the eye-piece as though to avoid a coming blow. Then he got up from his chair and laughed. "What an ass I am! That's Mr Parmenter's fleet; but what monsters they do look through a telescope like this!"
At one end there is the object-glass, and at the other end the eye-piece, and of course it is obvious that with an instrument of this construction it is to the lower end of the tube that the eye of the observer must be placed when the telescope is pointed to the skies.
One of the eye-piece lenses had been lost or broken, for, as the youth raised the glasses to sweep again the distant sea-line, he covered the left-hand cylinder with a flat, oblong object a printed book.
In this way the image of the star will appear, not as a point, but as a round disk of light. If the telescope is perfect, this disk will appear round and of uniform brightness in either position of the eye-piece. But if there is any spherical aberration or differences of density in different parts of the glass, the image will appear distorted in various ways.
The astronomer, furnished with an eye-piece, and wishing to examine that image, must necessarily place himself beyond the point where the rays that form it have crossed each other; beyond, let us carefully remark, means farther off from the object-glass.
Then, having swung the microscope on its stand into a horizontal position, he produced from the camera case a slab of mahogany with three brass feet, on which he placed the camera, and which brought the latter to a level with the eye-piece of the microscope.
The front of the camera was fitted with a short sleeve of thin black leather, and into this the eye-piece end of the microscope was now passed, the sleeve being secured round the barrel of the microscope by a stout indiarubber band, thus producing a completely light-tight connection. Everything was now ready for taking the photograph.
"Here's something rather good," he said, and with a start and an effort she took his place at the microscope, while he stood beside her and almost leaning over her. She found she was trembling at his nearness and full of a thrilling dread that he might touch her. She pulled herself together and put her eye to the eye-piece. "You see the pointer?" he asked. "I see the pointer," she said.
When I directed my 20-inch reflecting telescope almost at random to any part of the firmament, especially to any portion of the Milky Way, the sight of myriads of stars brought into view within the field of the eye-piece was overpoweringly sublime.
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