On the morning of Monday 29th May, Mercury will be at its greatest western elongation (or in other words its furthest distance) from the Sun, so if you were looking towards the east just before sunrise around 5am, there would be a good chance to see it.  Best to not risk using a telescope though as the Sun will be rising in the same direction shortly afterwards.

If early mornings are not your thing, wait until it gets dark on the Monday evening, when a slightly gibbous Moon will be located towards the south west.  It is a perfect opportunity to observe the Clair-obscur lunar visual effect known as the Jewelled Handle.  The feature will be on the sunlight terminator to the north of the Moon's face.

Take your telescope outside and point towards the west a couple of evenings later, around 11pm on Wednesday 31st to see Venus setting below the horizon with Mars a little above it and to the left.  Venus will appear to be about 50%-lit.....a bit like a quarter Moon.

Mars will be just to the right of the Beehive open cluster of stars, also known as M44 in the Charles Messier catalogue of deep sky objects.  It is one of the nearest clusters to us, only about 610 light years away.

Finally, on the evening of Saturday 3rd June, we have a Full Moon.  At 11pm it will be situated towards the south south east, just above the red supergiant star Antares.

Venture outside just after dark, say around 10pm, on Wednesday 24th and there is a great viewing opportunity if you look towards the west.  A 25%-lit waxing Crescent Moon will be just above planet Mars.  Mars  has a magnitude of around +1.5 at the moment, so it will be easy to spot with the naked eye and it has an obvious reddish tint.

Looking to the right of the pair and a bit further down, Venus is still spectacular, shining very brightly.  If you aim even a small telescope at Venus, it is possible to see its phase and the planet currently appears to be about 50%-lit or in other words, it will look like a tiny Quarter Moon.

The evening of Saturday 27th is a chance to spot one of the Clair-obscur lunar visual effects in your telescope - the Stars of Aristillus.  The effect is caused by sunlight reflecting from the peaks in the middle of crater Aristillus.  The whole crater is only 55Km in diameter and it is estimated to be over 1.1 billion years old!  Around 10pm, the Moon will be located towards the south west.  The crater will be on the sunlight terminator, a little above the centre of the Moon's face.

Around this time of year is the start of the Noctilucent Cloud season.  These night-shining clouds are caused by ice crystals in the upper atmosphere scattering light during astronomical twilight, so are viewable towards the north west horizon for up to a couple of hours after sunset.  Similarly, they can be detected a couple of hours before sunrise if you are looking towards the north east.

How about a daytime astronomy challenge for a change?  Between 2 and 3pm on Wednesday 17th a rare Lunar occultation of Jupiter occurs when the gas giant planet is obscured from our view by the Moon.  Well at least it would be if you lived in the north of the country!  From southern latitudes like down here in Somerset, the pair will just appear to get very close together.

But hang on.....it will be daylight!  The Moon will be visible to the naked eye towards the south west, but quite hard to see as it will only be a thin 7%-lit waning crescent shape.  Spotting Jupiter to the left of the Moon will require binoculars or a telescope, but there is an inherent danger in doing this as the Sun will only be a few degrees to the left of them and you must never catch even a brief glimpse of the Sun in an optical instrument.  Because binoculars and telescopes collect light and then magnify it, accidentally doing this with the Sun would cause instant and permanent blindness.

So how can it be done safely?  Either stand behind the wall of your house with your binoculars or set-up your tripod behind a fence so that you are in the shadow of the Sun, but have a clear view to the right of it.  That way, if you point towards the Sun by mistake, you will only be looking at a blank wall.  I cannot stress enough how important this safety measure will be!

There is one good opportunity so spot the International Space Station next week on Tuesday 16th at 12.13am when the ISS will appear in the west and spend six minutes passing almost directly overhead before disappearing towards the east.

The brightness or magnitude of most stars is pretty constant.  They only twinkle because the light being radiated from them is distorted by our atmosphere, but their overall magnitude remains the same night to night.  Some stars are classed as "variable stars" and these can vary considerably in magnitude - some stars swell and shrink in size and others may have their light partially blocked from reaching us as an exoplanet orbits around them.

This week try having a look at one such variable star, R Coronae Borealis which is located towards the centre of the "U-shaped" constellation Corona Borealis.  Changes in its chemical composition mean the star can vary between a magnitude of +5.7 at maximum when it is just visible with the naked eye, down to a minimum of +15 which is serious telescope territory!

Closer to home and definitely not needing a telescope, there are some excellent opportunities to observe the International Space Station next week, but you will have to stay up late.  The dates for your diary are Thursday 11th at 2.40am, Friday 12th at 1.52am and Saturday 13th at 1.01am.  In each case, the ISS will appear over the horizon to the west and spend 6 - 7 minutes passing almost directly overhead before disappearing to the east.

The coming week is not ideal for trying to observe faint deep sky objects because we are near a Full Moon which produces too much light pollution for serious observing.  Instead I'm going to concentrate on a few brighter targets.

If you go outside around 10pm on Friday 5th and look to the west, it is still possible to see Venus shining brightly as it begins to set below the horizon.  Viewed through a telescope, Venus shows phases just like our Moon and you should see it as what appears be a quarter phase.  Above and to the left of Venus will be the red planet Mars.

When you've had enough of identifying geometric shapes, turn your gaze towards the south east and a Full Moon will have just risen above the horizon.

Early morning on Saturday 6th and Sunday 7th is the peak of the Eta Aquariid meteor shower, but as that is only a couple of days past the Full Moon, the viewing of any shooting stars will not be great.  If you are up around 4am, the constellation of Aquarius briefly pops up above the horizon towards the east south east.  Even if the radiant point of the shower has dipped below the horizon again, it should still be able to see the meteors streaking across the sky before dawn.

Screenshots courtesy of Stellarium

Copyright Adrian Dening and Radio Ninesprings 2023