A little ramble through 19th century astronomy - report from the Belgium Academy on Jupiter and Mars in 1871-73

 Bulletin de I Académie Royale des Sciences, des Lettres, et des Beaux Arts de Belgique, 1873, No. 11.

Among the papers in this report of the work of the Belgian Academy, is one by M. Terby, giving the results of observations on Mars and Jupiter in 1871 and 1872-3. It is illustrated by fourteen figures of Jupiter and twelve of Mars. The Jupiter drawings exhibit some remarkable changes in the two polar “ calottes ” or dark parts.

 In 1872, the north polar region was usually darker than the southern, while in 1873 the contrary was often the case, though the southern one was always of smaller dimension. The drawings also exhibit curious variations in the shape of the belts, as seen at successive dates when the rotation of the planet caused it to present the same portion of its surface to the observer. The Mars sketches may be advantageously compared with Browning's stereographs, and with drawings he published in the Intellectual Observer, vol. xii. ; but M. Terby’s telescope, only 9 centimétres of useful aperture,” or little more than 3.5 inches, could only give a distinct view of the more delicate markings in exceptionally fine weather.

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