The original Nell-Hammer (1990) was derived from the Nell projection. This modified version was introduced in 1949 by Karlheinz Wagner and allows to set arbitrary standard parallels. The image shows the modified Nell-Hammer with standard parallels at ≈ 42°12′ N/S, which were chosen by Wagner to offer a closely matching alternative to Eckert IV which can be calculated using a considerably easier formula.
(The exact value that I used for the standard parallels is 42°12′49.284″ – not that it really matters…)
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Specified in [square brackets]: Actual size of the projection
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