Page:Medical Heritage Library (IA b30513546).pdf/73

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Astronomical Dialogues.
59

You know, Madam, said I, that it hath been before observed to you, that the Astronomers have Instruments made on purpose for it, which do it with great Accuracy: But as for your present Enquiry, how high any Star or Planet appears to be above the Horizon, you may guess at it nearly, thus: The Distance you see here between the two Pointers of the Great Bear before-mentioned, is nearly five Degrees; and this being a Distance always ready, and in view, will serve you very well to guess at the Height of any Star above the Horizon; or at the Distance of one of them from another; so as to enable you to find out any of them in the Heavens by the Help of the Globe, or any Planisphere, or Map of the Heavens: Use will make this easy to you; and when you come also to consider, that from the Zenith to the Horizon, being 90°, half that Distance mnst be 45°; one third of it 30°; a sixth of it 15°; a ninth Part of it 10°, &c. you will, by Degrees, easily gain a practical Knowledge of these Distances.

But if you please we will go on: Almost South-west, at this Time, and about 43° high, will appear another Star of the first Magnitude, called Deneb.Deneb, which is in

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