Astronomical Notes for April. Mercury is in elongation as a morning star on April 20, but is not well placed for northern observers. Jupiter and Mars continue to be well placed, in Leo. Mars is stationary on April 13, not far from Regulus; after this it will approach Jupiter until the evening of June 4, when they are only 15′ apart. Neptune is also in Leo. Venus and Uranus are too near the sun for observation; the former becomes an evening star on April 21, but will not be easily observable until June.