The Night Sky in May 2025
Everyone will now notice that the days are getting longer and the nights shorter and these divisions will increase as the month progresses. Certainly the blackbirds in my garden are up at 05:00 to 05:30 with a bright dawn chorus.
It will be harder to get a fully dark sky with the shorter nights.
These changes are firmly connected to our seasonal changes which are caused by the fact that the rotation of the Earth is inclined at 23.5º to our path of rotation around the Sun. As the Earth rotates the Sun appears to climb higher and high in the sky from spring to summer and then reverses its climb in the autumn and winter. If the Earth were totally upright we would have no seasons at all.
The actual solstice occurs on 29th May marking the start of summer in the Northern Hemoisphere.
The Moon
As we start May the Moon is in the 4th day of its cycle, and will reach full phase on the 12th May, it has various names linked to it. ‘Flower Moon’ or ‘Blossom Moon’ were used by North American First Nation peoples due to it occurring when the blossoms hung heavily in North America’s. The Anglo-Saxons referred to it as the ‘Milk Moon’.
The next new Moon starts of the 27th May.
If those of you who came to the talk on the 28th April will remember Mike talking about Mare Oriental being an Mare on the limb of the Moon and harder to observe. The Moon’s libration this month is such that it can be better seen in pots full Moon until the 24th May.
Meteors.
6th May prior to dawn is a decent opportunity to try and capture or view the Eta Aquarids They actually started on 19th April and go through until the 28th May. The cause of this meteor shower is the Earth passing through the tail of debris from Halley’s Comet.
All that said this is not an easy shower to observe as the radiant is low in the dawn sky.
The Planets
Mercury is poorly positioned as it is to the west of the Sun
Venus is a pre dawn object and in crescent phase
Mars is the easiest planet to observe, it is close to the Beehive Cluster in Cancer between 1st to 7th May. It will be above the centre of the Beehive on the 4th & 5th.
Jupiter is now out to the west and low in the evening sky, by the end of the month it will pass out of our sight for a while.
Saturn will become a pre-dawn object by the end of May, its rings are still just about edge on to our view.and it is not until early July we start of see them opening up again.
Uranus and Neptune are hard to see, the former is lost to view in the Northern Hemisphere and Neptune is lost in the dawn twilight
Meteors
This month we have the Eta Aquarids shower, which peaks around the 5th May at 22:00. These are the remains of part of Halley’s comet.
As the name suggests they appear from a radiant within the constellation of Aquarius, you will be fighting the dawn light if you do get to observe them.
Eta Aquarid meteor shower 2024: Everything you need to know | Space
Eta Aquarids Meteor Shower 2024 (timeanddate.com)
The Stars
With the shorter nights we have to wait longer before getting a true dark sky so that we can see the stars and brighter deep sky objects more clearly. This is usually about 1.5 hours after sunset.
Leo continues its march across the skies and the 1st quarter Moon will be just above Regulus the brightest star in Leo, which also forms part of the asterism called the sickle.
My favourite constellation that makes its appearance at this time of the year is Hercules. It is easily identified by the four stars that make a keystone shape. Indeed this asterism is known as the ‘Keystone’
Using a pair of binoculars look to the space 1/3rd down between the two stars that form a line on the right side of the keystone. You should pick out a fuzzy circular formation. Much like a spider egg ball.
This is M13 and is a globular cluster and lies 22,200 light years away and the orb of stars is about 145 light years across. It contains several hundred thousand stars, some of which are very young. It is easy to pick out even with small telescopes.
Another good globular target in Hercules is M92. To find it sweep up from Pi (Π) Herculis which is the left upper star of the Keystone. It is 26,700 light years distant.
Hercules (constellation) – Wikipedia
May is the start of the galaxy season. The area between Virgo to the east, the tail of Leo to the west and Coma Berenices toward the XXXX marks region of the night sky packed with galaxies, there are 14 Messier objects alone in this patch.
Ursa Major is well positioned high in the night sky making it easier to observe and image M101 and M51.
The Sun continues (when we can see it!) to be quite active and we have been posting Face Book website. These show sunspots as well as surface activity on the Sun such as flares and prominences.
I always post warnings when I show these images as it is extremely dangerous to view the Sun without specialist filters and telescopes. I am still shocked that cheaper imported telescopes still include a so call sun filter which is a simple dark filter that can be screwed into a telescope eyepiece. Throw them away, the magnified light passing through the telescope and can heat and cause these to shatter.
If you want to see what is happening on the Sun real time use this website, the SOHO solar telescope. This displays it in a number of spectra including white light, hydrogen alpha and calcium (K).
Solar and Heliospheric Observatory Homepage (nasa.gov)
Frank Dutton
Keep looking up.
