Solarium is an obsolete constellation of unknown origin and dubious validity. It appears only in Elijah Burritt's Atlas of the Heavens, an eight-page supplement to his Geography of the Heavens, which was published in various editions from about 1835 to 1855 (the page containing the (cropped) illustration below states that it was published in 1835). It lay next to Horologium, between the head of Hydrus and the tail of Dorado; but it is doubtful that it was ever used by any professional astronomer. However, Burritt's Atlas was the last and one of the most successful atlases of this kind to be published in America, and was undoubtedly pored over by a generation or two of fascinated Americans (for instance, his grandmother's copy of the work was one of H. P. Lovecraft's most prized possessions). So although of no real astronomical importance, Solarium does have a place (though a very small one) in the history of astronomy. (Note: The possessive and abbreviated forms shown above are in no way official; they merely represent the way they might have been assigned, if the constellation had been accepted.)