The Constellation of Cancer the Crab

The silver stars and silhouette of Cancer the crab are illustrated in this handmade block print. I printed an edition of eight prints, 7 inches by 10 inches (17.8 cm by 24.8 cm) on lovely, handmade, Japanese kozo (or mulberry) paper with a deckle edge. The word Cancer and symbol ♋ appear at the bottom of the image. The lines linking the constellation appear in black-on-silver or silver-on-black as appropriate. There are two star clusters, shown as circles filled with stars. The Beehive Cluster (M44 in the Messier star catalogue) is inside the crab itself. The open star cluster M67 appears by the lower claw.

Cancer is one of the dimest zodiac constellations (or those constellations which cross the ecliptic). If you imagined all celestial bodies we see in the night sky as mapped onto a sphere (the Celestial Sphere) around our Earth, the ecliptic would be the line you would draw to map the apparent path of the Sun through the various constellations. The ecliptic is marked as the dashed line in this print. Because of its dimness Cancer was often considered the "Dark Sign", quaintly described as black and without eyes. It has been recognized as various crustaceans by different peoples at different periods. I've shown it as a crab, which is most common today.
______________________________________________________________

I realize I have many series on the go now. This suits me better than a single-minded approach. I like to switch it up to avoid having creativity blocks. I'm working on completing the other 9 zodiac constellations; I plan two more local bee species; I have 7 provinces and three territories yet to print; I plan monograms for the other 18 letters of the alphabet. This is on top of open-ended series, like 'figures from the history of science' or the 'terms of venery' series, or just plain 'animals'. I have series I would continue (like the 'Imaginary Friends of Science' series) if I ever discovered any further subjects. I also have possible future series, quietly brewing in my brain.

Henrietta Swan Leavitt

This is a first edition lino block print of the woman who was able to set the scale of our Universe. A portrait of Henrietta Swan Leavitt is printed in silvery lavender ink on Japanese kozo (or mulberry paper). Behind her is a line showing stellar luminosity (capital L with subscript sun-symbol, a circle with a dot) as a function of time (t). She is printed over constellations in gold (Cepheus, Cassiopeia, Draco, Ursa Minor and Andromeda). The first edition is a run of 6 prints, each 10" by 12.5" (25.4 cm by 31.8 cm).


Henrietta Swan Leavitt (July 4, 1868 – December 12, 1921) was an American astronomer. In her day, women scientists were regularly hired to do menial chores. She was hired to count images on photographic plates as a "computer".* In studying these plates, in 1908 she was able to deduce a ground-breaking theory, which allowed Hubble's later insight about the age and expansion of the universe**. Her period-luminosity relation for Cepheid variable stars radically changed modern astronomy, an accomplishment for which she received little recognition during her lifetime.

Cepheid variables are a class of pulsating star. They are named for the star Delta Cephei in the Cepheus constellation. The relationship between a Cepheid variable's luminosity and pulsation period is quite precise. It had not been obvious to tell whether a star was dim because it was less luminous, or whether it was merely further away. Swan Leavitt's discovery lets astronomers use Cepheids as "standard candles". They allow astronomers to determine distances to celestial objects and form the foundation of the Extragalactic Distance Scale.



This April, the Mad Scientists of Etsy are celebrating Henrietta Swan Leavitt, who died too young, but accomplished more than most and greatly added to our understanding of our place in the Universe.

Also, she's a serious contender to battle Annie Jump Cannon for "best astronomer middle name".



*These "computers" were quite literally treated like automatons.

**Ejnar Hertzsprung used her discovery to plot the distance of stars; Harlow Shapley used it to measure the size of the Milky Way; and Edwin Hubble used her work to ascertain the age of the Universe.