Posted by on May 25, 2019 in Main |

Society member Richard Crabtree Observing Orion.

This is the mid point of the year and the night sky is never quite getting dark, especially in Yorkshire. It’s not the greatest month for spotting faint stars. Only the brightest stars can be seen. You can take advantage of the soft, warm weather to acquaint yourself with the summer constellations of Hercules, Scorpius, Lyra, Cygnus and Aquila.

Jupiter and Mercury will be putting on their best shows of the year, and look for the bright stars like Vega in Lyra, which is high in the eastern sky, as is the Summer Triangle it forms with Altair in Aquila and Deneb in Cygnus returns to prominence.

June brings our summer solstice on the 21st of this month.

There are two very nice objects to spot with binoculars in the eastern sky well after dark this month. Two thirds of the way up the right hand side of the 4 stars that make up the “keystone” in the constellation Hercules is M13, the best globular cluster visible in the northern sky.

Just to the left of the bright star Vega in Lyra is the multiple star system Epsilon Lyrae often called the double-double. With binoculars a binary star is seen but, when observed with a telescope, each of these two stars is revealed to be a double star – hence the name!

The Sun follows a shallow arc below our North horizon overnight, the geometry allowing views of noctilucent clouds, whose silvery-blue tracery may gleam low down between the northwest after nightfall and the northeast before dawn. Noctilucent clouds are formed by ice crystals coalescing around dust particles. They float near 82km in altitude where they reflect sunlight after our normal clouds are in darkness.

Two planets vie for our attention in the evening sky.

Mars shines at magnitude +1.8, in Gemini and sets around 11pm.

This month it joined by Mercury, making its best evening appearance of the year. Look for the innermost planet about 10pm, in the north-west. At the start of the month Mercury is just above the horizon at magnitude –1.0. The tiny world heads upwards towards fainter Mars, fading as it goes. Mercury is at magnitude +0.2 (Three times brighter than Mars when the planets pass very close on the 18th June). For the rest of June Mercury loops downward fading to magnitude +1.1 by the end of the month.

Jupiter is now visible all night long, and is at its closest to Earth, on 12th of the month, at 641million kilometres. With binoculars or a small telescope, you can spot its four largest moons. The gas giant lies in Ophiuchus, and is by far the brightest object in the night sky at magnitude –2.6. On the 10th June, Jupiter is opposite to the Sun in the Sky. On the 16th the brilliant star just to the right of the Moon is Jupiter.

Rising around 11pm, fainter Saturn is shinning at magnitude +0.3 in Sagittarius. Neptune lying in Aquarius, rising about 1am, follows it. However it is so dim at magnitude +7.9 you will need binoculars or a telescope to see it.

Next up above the horizon around 2.3am, is Uranus. Lying in Aires, with a magnitude of +5.9. Finally there is Venus. Rising just before the Sun, at 4am. You may catch this morning star hugging the Horizon to the north-east at magnitude –3.9

Phases of the Moon for June

New Moon 3rd
First Quarter 10th
Full Moon 17th
Last Quarter 25th