Giant Jupiter becoming

With its lengthening days and increasingly twilit nights, May is hardly a vintage month for stargazing from Scotland’s latitudes. Official (nautical) darkness for Edinburgh lasts for more than five hours around midnight as the month begins but dwindles to nothing by the start of June and does not return until 12 July

Edinburgh’s sunrise/sunset times change from 05:30/20:51 on the 1st to 04:37/21:45 on the 31st, while the Moon is new on the 4th, at first quarter on the 12th, full on the 18th and at last quarter on the 26th.

Our charts show Leo diving westwards as the Summer Triangle formed by Vega, Altair and Deneb is climbing in the east. After the Moon, our most obvious nighttime object is the planet Jupiter which rises in the south-east 30 minutes before our map times and reaches less than 12° high in the south before dawn. In fact, look for the Moon above-right of Jupiter on the night of the 19th and closer to the planet’s left on the 20th.

The giant world is now edging

westwards against the stars of southern Ophiuchus and brightens from magnitude -2.4 to -2.6 as its distance falls from 678 million to 644 million km. The Jovian globe spans 45 arcseconds in midmay and telescopes show that it is crossed by bands of cloud that lie parallel to its equator. The four principal moons of Jupiter are also easy targets, though sometimes one or more hide from view as they pass in front of, or behind, the disc or are eclipsed in Jupiter’s shadow.

Saturn trails almost two hours behind Jupiter but is fainter at magnitude 0.5 to 0.3. It lies in Sagittarius, below the Teaspoon asterism, where it stands above the Moon but low down in the south-southeast before dawn on the 23rd. Always an impressive sight through a telescope, though not helped by its low altitude, its disc appears 18 arcseconds wide at mid-month, circled by rings that measure 40 by 16 arcseconds.

Mercury and Venus are too deep in the morning twilight to be seen at present, though Mercury slips around the Sun’s far side on the 21st. The morning twilight also hinders views of the Eta-aquarids meteor shower which peaks around the 6th-7th and brings swift meteors that stream from a point which hovers low in our east-south-eastern sky for two hours before sunrise.

Mars sets a few minutes before our star map times and may be hard to spot low down in our west-north-western evening sky. It stands between the horns of Taurus on the 1st and shines at magnitude 1.6 to rival the star Elnath, which lies 5° above Mars and marks the tip of the Bull’s northern horn.

Mars’ pinkish-orange hue is best appreciated through binoculars as the planet dims further to magnitude 1.8 and speeds 20° eastwards during May, crossing into Gemini at mid-month and sweeping only 0.2° north of the star cluster M35 (use binoculars) on the 19th. It recedes from 335 million to 363 million km during May but, at a mere 4 arcseconds in diameter, is too small to be of telescopic interest. Catch Mars above the slim earthlit Moon on the 7th.

NASA’S Insight lander used