Scientist of the Day - Thomas Elger

Thomas Elger, a British astronomer, was born Oct. 27, 1837. Elger published a lunar map in 1895, included in a book called The Moon. That in itself is nothing special--many people were launching maps of the moon in the last half of the 19th century. Lunar maps were getting larger and larger, portraying tens of thousands of lunar features. That was fine for the professional astronomer, but such maps, like the Schmidt map of 1878, fully six feet across, were useless for most observers. What was really needed was an up-to-date map that was simplified, filtering out the features that can only be seen in institutional telescopes. That was what Elger provided; a map that was easy to read, with legible type and clearly marked features.

The first image above is the first quadrant of the moon, a two-page folding plate, as it appears in Elger’s book. The second image is the same 1st quadrant, this time from Wilhelm Beer & Johann Maedler’s The Moon (1837), which we featured in this space on May 29, 2014, a map that was three feet across when assembled. One can easily appreciate the attraction of Elger’s book for amateur lunar observers. The last three images above show lunar quadrants 2-4, as they appear in Elger’s The Moon.

We included Elger's map in our exhibition, The Face of the Moon.

Dr. William B. Ashworth, Jr., Consultant for the History of Science, Linda Hall Library and Associate Professor, Department of History, University of Missouri-Kansas City