Johann Friedrich Julius Schmidt (25 October 1825 in Eutin, Germany – 7 February 1884 in Athens, Greece) was a German astronomer and geophysicist.

Julius Schmidt was tireless in his work, it was suggested by William Henry Pickering that he perhaps devoted more of his life than any other man to the study of the Moon.

He went to school at a gymnasium in Hamburg, where he impressed with his sense of form and drawing abilities and demonstrated a strong interest in science.

Reading Schröter's work and drawing the Moon became his main occupation, and it was not long until Schmidt devised a tripod for the telescope, which could go in both up-down and left-right motions.

Here, Schmidt measured the visual magnitudes and positions for Hora V of the Berlin Academy of Sciences star chart and catalogue project.

[5] He was not able to continue observing the Moon due to his job, but he still obtained numerous valuable drawings, and when he did not, what was seen was preserved in writing.

[3] From 1853 to 1858 he was director of Baron von Unkrechtsberg's private observatory at Olmütz (today Olomouc, Czech Republic), where he made only a few drawings, but undertook micrometric measurements of its mountains to further increase the knowledge of the Moon.

Accepting the offer would bring him a good salary, freedom to do the research he wants to do and a site with a large amount of clear nights per year.

He ran systematic studies on not only the Moon but also sunspots, color of stars, variable stars, meteors, comets, Saturn's rings, eclipses, twilight, zodiacal light, nebulas, weather, seismic activity, rotational period and diameters of the major planets and satellites of the gas giants.

Their discovery was published ten years later in 1876 with the work Über einige im Cape-Catalog fehlende Nebel.

[7][8] In 1866 he made the astonishing claim that Linné crater had considerably changed its appearance, which began a controversy that continued for many decades.

[9] He spent over two years on the first draft of his great Moon map encompassing the entirety of the lunar surface, gradually entering the results of his more recent observations from Athens, when he realized continuing this undertaking would not end well.

Schmidt was awarded the Valz Prize from the French Academy of Sciences in recognition of this selenographic work.

He asked the Berlin Academy of Sciences to provide him with a small telescope on an equatorial mount, so he could continue astronomical observations from his house.

When he passed, the King and Queen of Greece, professors, students and thousands of Greek citizens attended the funeral oration at his observatory.