Transcription: For faint objects, he must prepare charts so that the targets can be easily located. A night assistant arrives in the late afternoon and opens the observation slit so that the inside and outside temperatures are balanced as quickly as possible. This is particularly important on frosty winter days when trapped warmer air may well affect the image and even distort the optical surface of the mirror. This would result in poor images, delays in observing or even no observing at all. The electric and oil pumps to drive the telescope are switched on immediately after sunset. The giant telescope, weig ... File Comment Made in Intimate Arts
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