BBC Sky at Night Magazine
Your guide to the night sky this month
The dazzling evening planet Venus reaches its 25%-illuminated phase today. Venus can be seen shining in the evening twilight at mag. –4.5.
Through the eyepiece, Venus currently appears as a 20%-lit crescent, 43 arcseconds across.
A 74%-lit waning gibbous Moon appears near mag. –2.3 Jupiter and +0.8 Saturn as they rise above the southeast horizon at 02:30 BST (01:30 UT).
Today, Venus is rapidly increasing in apparent size, with 15%-illumination.
Mercury and Venus appear just 0.9˚ apart around 11:00 BST (10:00 UT), during the day.
The evening view will be easier to find, with mag. –0.5 Mercury moving slightly to lie 1.3˚ from mag. –4.1 Venus.
This morning, the now 64%-lit waning gibbous Moon remains close to planets Jupiter and Saturn. Look for the trio at around 03:20 BST (02:20 UT) when they should be visible low above the southeast horizon.
This evening look out for a thin 1%-lit waxing crescent Moon near to mag. –0.3 Mercury and –4.2 Venus. Through a telescope Venus now appears as a 5%-lit crescent 54 arcseconds across. Mercury appears 65% lit and 6.4 arcseconds across.
Venus is now becoming a slender crescent through the eyepiece of a telescope, today appearing just 10% illuminated.
This evening a 4%-lit waxing crescent Moon lies near to mag. –0.3 Mercury and –4.2 Venus.
Comet C/2017 T2 PanSTARRS appears close to galaxies M81 and M82 in Ursa Major.
This evening the 26%-lit Moon appears 2˚ to the east-northeast of the beautiful Beehive open cluster, M44.
Venus is now at 2% phase.
If you can catch a view of the Moon this afternoon through a telescope you should be able to make out the arc of light known as the Jewelled Handle. This occurs when the Jura mountain range around the edge of Sinus Iridum catches the early lunar dawn light.
Wednesday 20 20
This morning there is a good opportunity to see the shadow of the outer Galiean moon Callisto transiting across Jupiter’s disc. The event starts at 01:30 BST (00:30 UT) and ends at 05:13 BST (04:13 UT).
Tuesday 26 26
Noctilucent Cloud (NLC) season opens as we head towards the end of May. Last year gave some amazing displays. What will 2020 have in store?
Venus is now just 3%-illuminated.
Three popular clair-obscur effects occur today. At 15:25 BST (14:25 UT) in daylight the Lunar X and Lunar V will be visible along the terminator. Then at 23:15 BST (22:15 UT), the Face in Albategnius effect will be visible.
The annual Eta Aquariid meteor shower reaches its peak this morning. Although the shower has a peak Zenithal Hourly Rate (ZHR) of 28 meteors per hour, a low early morning radiant and full Moon in the sky will make this year’s display less than spectacular.
This morning it’s Ganymede’s shadow that can be seen in transit across Jupiter’s atmosphere. The transit starts at 03:40 BST (02:40 UT), mid-transit is at 05:28 BST (04:28 UT) and it ends at 06:55 BST (05:55 UT).
This evening it’s the turn of the weak
Eta Lyrid meteor shower to reach its peak activity. Although the peak ZHR is only 3 meteors per hour, the shower does have a radiant which is high in UK skies. A bright Moon will interfere.
This morning, at 02:00 BST (01:00 UT), Plato’s Hook makes its second appearance for the month. Turn to page 55 to find out more about it.
This evening it’s the turn of the clair-obscur effect known as the Eyes of Clavius.