by Geoff Chester, USNO Public Affairs | 30 May 2023 Amber Moonrise, Alexandria, Virginia Imaged with an Antares Sentinel 80mm (3-inch) f/6 refractor and a Canon EOS Rebel SL2 DSLR The Moon dives toward the southern reaches of the ecliptic this week, brightening the evenings as she skirts the southern horizon. Full Moon occurs on June 3rd at 11:42 pm Eastern Daylight Time. June’s Full Moon is popularly known as the Strawberry Moon due to the ripening wild strawberries that are a late spring delicacy. Other names associated with the June Moon are the Rose Moon, Mead Moon, and Honey Moon. Each of these names reflect on the Moon’s appearance when she is passing her southernmost path through the sky. Her glow must pass through more of Earth’s atmosphere, which preferentially scatters blue light, causing Luna to take on a slightly amber tinted face. Look for the Moon near the bright star Spica on the evenings of the 30th and 31st; on the evening of the 3rd her full disc rises just east of the ruddy star Antares, the brightest star in the constellation of Scorpius, the Scorpion. The Moon’s brightening light makes identifying the stars of spring difficult for the urban skywatcher. The signature constellations of the season lack the bright luminaries of the winter and summer skies, so we have to hope for very clear sky conditions to trace them out. As evening twilight fades, though, one of those bright stars is well-placed in the southwestern sky. Regulus, the “heart” of Leo, the Lion, stands as the only first-magnitude star in this part of the sky, and a clear night should allow you to trace out the “Sickle” asterism above Regulus that forms the Lion’s “head”. If you have a small telescope, take a look at the next-brightest star above Regulus. This is Algieba, and it is one of my favorite double stars of the spring sky. A good 3- or 4-inch telescope will reveal a close pair of yellow-hued stars that contrast nicely with the pale blue tint of Regulus. Located about 130 light-years from Earth, the pair orbit each other once every 500 years. High in the northern half of the sky you should be able to find the seven stars that make up the asterism known as the “Big Dipper”, which is part of the much larger constellation of Ursa Major, the Great Bear. Also known as “The Plough” in Great Britain or “Charles’ Wain” in much of Europe, it holds another nice double star for both naked eye of telescopic viewing. If you look carefully at Mizar, the star that forms the bend in the Dipper’s “handle”, you may notice a dimmer star tucked close by. Known as Alcor, the ability to see it was once considered as a test of good vision. Point your telescope at the pair and you will see that Mizar is itself a double star. This was the very first double star I observed with my first telescope, and I often return to it on evenings where the sky is too bright to look at the many galaxies in the area. High in the east you will find the northern sky’s brightest star, Arcturus. An easy way to find it is to follow the arc of the Dipper’s handle and “arc to Arcturus”. Continue that line to “speed on to Spica” to round out the brighter objects of the early evening. By midnight the bright stars of summer make their way into the eastern sky. The signature asterism of the season consists of three bright stars that form the Summer Triangle. The brightest of these is Vega, which leads the group into the sky. Vega is one of our closer neighbors in space, a mere 25 light-years away. Even closer is Altair, the southernmost of the Triangle stars. It lies just under 17 light-years away. The third and faintest member of the Triangle is Deneb, but don’t let its perceived dimness fool you. It is located some 100 times farther away than Vega, which means that it must shine with the light of about 200,000 Suns to appear as bright as it does to us! Venus reaches her greatest elongation from the Sun on June 4th. Through a telescope the planet will reveal a phase that resembles the first quarter Moon, and over the next few weeks she will become a gradually slimming crescent. Venus still appears to close in on Mars, but she won’t quite catch her ruddy rival. Mars continues his eastward trek through the springtime constellations. This week the red planet crosses the heart of the dim constellation of Cancer, the Crab. On the evenings of June 1st, 2nd, and 3rd he will pass directly through the center of the binocular star cluster known as The Beehive. Look for Saturn in the southeastern sky in the wee hours. The ringed planet rises shortly before 2:00 am local time and is well-placed for viewing as morning twilight gathers. If you’re up before the Sun you can welcome giant Jupiter back to the sky. He rises just before 4:00 am and is just over 10 degrees high in the east an hour later.