Monday 22nd to Sunday 28th April 2024

Monday 22nd sees the peak of the Lyrids meteor shower, but I am not going to recommend it highly, as light pollution from an almost-full Moon will make the viewing difficult.  If you did want to try hunting those elusive meteors that can occur at a rate of 18 per hour, the radiant point where the shooting stars appear to originate from is just to the right of the bright star Vega in the constellation of Lyra.  At 11pm, Lyra will be located towards the north east, with the Moon much further south.


The Full Moon actually occurs two days later, on Wednesday 24th.  By 11pm it will have risen above the south east horizon.


Coincidentally, at that time, the tilt of the Moon makes a favourable opportunity to spot one of the rarer clair-obscur visual effects on the lunar surface known as the "Zeno Steps".  With your telescope, find the crater Zeno towards the top right of the Moon and then you should be able to spot what looks like three steps leading down to the crater.  I have provided an image below, courtesy of astronomer Danny Caes, to help locate the feature.


Because of the way the Moon orbits around us, if you went outside at the same time a couple of nights later and looked in the same direction, you wouldn't see it.  By Saturday 27th, the Moon will have become a 90%-lit gibbous shape and it won't rise above the south south east horizon until after 1am that morning. If you do venture outside to see it then, the bright red supergiant star Antares will be just to the right of the Moon.




Monday 15th to Sunday 21st April 2024

The evening of Tuesday 16th sees a 60%-lit waxing gibbous Moon which, if you venture outside around 9pm, will be located towards the south.  To the right of the Moon (more south west) and much closer to the horizon will be the brightest star in the night sky, Sirius and further right again, the constellation of Orion.


At the same time, just below and to the right of the Moon will be a nice target for a small telescope or binoculars - the Beehive open cluster of stars, also known as M44 as it is one of the deep sky objects catalogued by Charles Messier in the late 1700s.


The cluster is one of the closest to the Earth, approximately 600 light years away and it contains over 1000 stars.  With a very dark sky, it can just be seen with the naked eye and would then look like a fuzzy blob, but that won't be possible this time around because of light pollution from the nearby Moon.  With your telescope, you should be able to see the brighter individual stars though.


M44 sits in the constellation of Cancer, between the constellation's delta and gamma stars called Asellus Australis and Asellus Borealis.  Stars in a constellation are allocated letters of the Greek alphabet, in decreasing order of their brightness or magnitude.  Significant stars are also historically given names and in the case of Asellus Australis and Borealis, the translation from Latin is "Southern and Northern Donkey"!


Moving away from donkeys, due to the popularity of this winter's astronomy evenings at Ham Hill, I have agreed to run one further session on Friday 26th April.  Places can be booked via the Visit South Somerset website.



Monday 8th to Sunday 14th April 2024

Although by now, all the chocolate eggs will be long-gone for another year, someone asked me a question the other day about why Easter always seems to occur on different dates and as the reason is astronomical, I thought I would share it here.


The spring or Vernal equinox, when the Earth's tilt of 23.5 degrees is sideways on to the Sun and we therefore have equal periods of daylight and darkness, takes place on 21st March each year.  Easter Sunday is always the first Sunday after the first Full Moon after the equinox.


On a completely different subject, Mars and Saturn will appear very close together on the morning of Thursday 11th.  They will be tricky to spot as day breaks, but try looking towards the east south east at 5.30am and the pair will be just rising above the horizon.  Please don't be tempted to use binoculars or a telescope though, as the Sun will be rising in the same spot and you don't want to risk catching an accidental glimpse of it in your eyepiece!


Friday 12th is an excellent opportunity to identify the longest valley on the Lunar surface known as Vallis Rheita.  You will need a small telescope.  At 10pm, a waxing Crescent Moon will be located towards the west, with the constellation of Orion to the left of it.  Vallis Rheita is situated  near the Moon's south east limb and I have included a photograph below to help find it, courtesy of astronomer Andrew Planck.




Monday 1st to Sunday 7th April 2024

The coming week is a good opportunity to go hunting for faint deep-sky objects as during the hours of darkness, the Moon will be below the horizon and so not causing any light pollution.  The clocks will have just moved forward and we are now running on British Summer Time BST - all the times I quote for the next six months will be in local time to keep it simple.


Let's start with a comet - those icy visitors from the far reaches of the Solar System.  Comet 12P/Pons-Brooks could even be just visible with the naked eye at a magnitude of around +4.8 at the beginning of April.  If you venture outside just after dark, say around 9pm and look towards the west, Jupiter will be easy to spot.  To the right of Jupiter will be the constellation of Aries, just about to set below the horizon.  The comet will be very close to the bright star Hamal in Aries.


The "12P" in the comet's name indicates that it was the 12th comet to have the periodic nature of its orbit calculated and it takes 71 years to complete a full orbit, this time reaching "perihelion" when it is closest to the Sun, later in April.  Although it is believed that the comet was first observed way back in the 1300s, it was officially identified by French astronomer Jean-Louis Pons in 1812.  Its existence was then confirmed by William Robert Brooks in 1883 who, along with Jean-Louis, was an avid comet-hunter.

Image courtesy of Wikipedia

If you have brought your telescope outside to try and see the comet's tail, there is also an opportunity to observe planet Uranus, which will be located a little above Jupiter.  It will have a magnitude of about +6.0 so will not be visible with the naked eye.




Monday 25th to Sunday 31st March 2024

On Monday 25th we have a Full Moon, but you will need to be an early riser to catch it as by 5am, a little before dawn, the Moon will be setting below the horizon to the west.

If you would prefer to venture outside on the Monday evening instead, there is an excellent opportunity to observe the International Space Station.  It will appear towards the west at 7.37pm and spend six minutes passing almost directly overhead, before disappearing to the south east.  You are looking for a pinpoint of light, like a star, but the dot is silently moving across the sky.
30 Second time-lapse photograph of the ISS courtesy of NASA

If you miss that one, there is another chance to see the ISS at 7.39pm on Wednesday 29th, where again it will be visible for around six minutes travelling west to east, but this time the ISS won't appear quite so high in the sky.


The reason why you only sometimes see the ISS is because its orbit around the Earth is inclined at 51.6 degrees.  If the orbit was zero degrees, then the ISS would be permanently flying over the Equator.  If it was 90 degrees, then the ISS would be passing directly over the north and south pole.  Every time the ISS passes between the northern and southern hemisphere, it crosses the equator at that angle of 51.6 degrees.   It moves at 27,600 kilometers per hour and at that speed, takes just over ninety minutes to complete one orbit.  During that time, the Earth has rotated a bit, so each orbit appears to be in a different place and only some pass over the UK.

ISS Orbit Diagram courtesy of Wikipedia

Of course it also has to be near dawn or dusk so that sunlight reflects off the enormous solar panels, otherwise you won't see a thing!

ISS Image courtesy of Wikipedia



Monday 18th to Sunday 24th March 2024

How about a bit of a visual challenge if you like early mornings?  Look towards the east south east at 6am on Friday 22nd to see Venus just rising above the horizon.  It should be quite easy to see with a magnitude of -3.8 so that's not much of a challenge at all!


At the same time, just below and to the right of Venus will be Saturn - much harder to spot in the dawn sky with a magnitude of +0.8


Please remember that the Sun will be rising in the same place so don't be tempted to use a telescope to see Saturn's rings - this is purely a "naked eye" experiment!


If instead you look in the same direction (east south east) around 8pm on Saturday 23rd, a much easier target to find will be a 98%-lit waxing Gibbous Moon.  That's almost a Full Moon which occurs two days later.


You could also have a go at trying to identify the constellation of Leo "the Lion" that will be directly above the Moon.  Archaeological evidence places Leo as one of the earliest recognised constellations, dating back as far as 4000BC with the Mesopotamians.


Mercury can be another difficult planet to spot because it always appears close to the rising or setting Sun.  On Sunday 24th Mercury reaches its furthest elongation from the Sun and it actually sets nearly two hours after the Sun.  The planet will be easy to locate, shining at a magnitude of -0.1 if you look towards the western horizon from 7pm.


At the same time, Jupiter will make another nice target above and to the left of Mercury.




Monday 11th to Sunday 17th March 2024

I'm going to focus (no pun intended) on the Moon and other targets in the night sky that will appear close to it during the coming week.

Firstly, about half an hour after sunset on Monday 11th, it may be possible to just see a faint 2%-lit Crescent Moon with a magnitude -1.2 planet Mercury a little to the right and below it.  If you are outside around 6.15pm, the pair will be located towards the west horizon.

At the same time, a bit higher and to the left of the Moon will be planet Jupiter shining brightly at a magnitude of -2.0


If instead you look towards the west around 9pm on Wednesday 13th, the Moon will be a 16%-lit crescent by then and Jupiter will appear to be very close to it.  Above them will be the Pleiades open cluster of stars, with the constellation of Orion further to the left.


Try the same trick again at the same time the following evening, on Thursday 14th and the Moon will appear to be closer to the Pleiades.  This is because the Moon is very close to us in astronomical terms and is orbiting around the Earth, while everything else in the night sky is much further away and only appears to move because WE are moving!  By Thursday the Moon will be a 26%-lit crescent as it heads towards a "first quarter" phase that I talked about last week.


Finally, around 9pm on Saturday 16th, the Moon will again be located towards the west, but much higher in the sky and now it will be a 46%-lit crescent - almost a first quarter.  Immediately above it, try to spot the star Elnath which is the beta star in the constellation of Taurus.  It will have a magnitude of around +1.6 while below it (and a much easier target) will be the alpha star in Taurus, Aldebaran.




Monday 4th to Sunday 10th March 2024

There's nothing particularly remarkable to recommend during the coming week, but on Sunday 10th March there is a New Moon.  This phase of the Moon means that the Sun is illuminating the side that we can't see from the Earth and the side of the Moon facing us is completely shadowed.....or in other words, you won't see it!


The Moon takes 27.3 days to orbit around the Earth and as sunlight hits it at different angles, then you see the different phases.  After a New Moon it appears as a crescent shape, followed by a quarter, then a Gibbous Moon leading up to a Full Moon.  Then everything works the other way around - it becomes a Gibbous Moon, back to a quarter, followed by a crescent and ending up with a New Moon again.


If the phase is "waxing" it means getting brighter or heading towards a Full Moon.  If the phase is "waning", that means getting dimmer or heading towards a New Moon.


To add to the complexity, if you see a Full Moon and go back outside  27.3 days later, you won't see another one!  You would have to wait 29.5 days because while all this has been going on, the Earth has travelled 1/12 of its yearly orbit around the Sun and so all the angles have changed!  In ancient times, this 29.5 days was called a Lunar Month because it was what people actually observed.


Finally, I am running the last of this winter's astronomy sessions at the Ham Hill Visitors Centre on Friday 8th March, starting at 7pm with a talk on general astronomy, followed by some star gazing if it's clear.  There are still a handful of places available and booking is through the Visit South Somerset website.