Monday 21st to Sunday 27th February 2022

An open cluster of stars is defined as a group of up to several thousand stars that were formed in the same molecular cloud and are held together by each other's gravity.  All the stars within a cluster will be a similar age and they gradually drift apart over many millions of years.

If you look fairly high up towards the south east around midnight next week, it is possible to see the open cluster of stars known as Melotte 111 with the naked eye.  Firstly find the constellation of Coma Berenices which is located between the constellations of Bootes and Leo.  The cluster will be situated slightly to the right of Coma Berenices.

Although the cluster had been known about for a long time, Charles Messier never bothered to include it in his catalogue of deep sky objects, so it doesn't have an "M" number.  Back in 1915, a British astronomer called Philibert Melotte included it in his list of star clusters and it was number 111 that he recorded, hence the name.  The cluster contains around 40 brighter stars that are approximately 280 light years away from us and the brightest of these form an obvious "V" shape.


On Thursday 24th around 9pm, the constellation of Gemini reaches its highest position in the night sky towards the south.  There will be no light pollution from the Moon because it will be below the horizon, so it's an ideal time to spot an open cluster that Charles Messier did bother to catalogue!  The cluster is known as M35 and it is much fainter, so you will need to use binoculars or a small telescope.  This cluster is a lot further away from us - around 3,800 light years.  It is located near the foot of one of the Gemini twins.




Monday 14th to Sunday 20th February 2022

On the morning of Wednesday 16th, planet Mercury reaches its greatest western elongation from the Sun.  What on Earth does that mean?  In practical terms, Mercury appears the furthest it ever gets away from the Sun and can be viewed popping up over the south east horizon a hour before sunrise.

If you look towards the south east around 6.30am you will see Venus shining brightly, with Mars a little below it and Mercury to the left of Mars very close to the horizon.
Please don't be tempted to use binoculars or a telescope to obtain a better view as if you accidentally catch a glimpse of the Sun in the eyepiece, it will cause instant and permanent blindness.
The evening of 16th sees a Full Moon rising in the east after dark and for the following few evenings, a bright Gibbous Moon.  You might think that it's ideal time to aim your telescope that way, but in reality the amount of sunlight being reflected from the lunar surface washes-out many of the interesting lunar features.
If astronomers are looking at such a bright Moon, they normally use a special filter in their eyepiece to lose most of light that their telescope has collected!  This is called a Neutral Density filter and it prevents your eyes from being temporarily burnt - the same as if you have accidentally stared at a light bulb - afterwards there is a black spot in your vision for a while.  Please don't try it!

To safely observe the Sun, astronomers use a totally different type of filter that is far more complex and expensive than the Neutral Density ones.



Monday 7th to Sunday 13th February 2022

On Monday evening, 7th February, there will be a 43%-lit crescent Moon with the planet Uranus just above it.  If you are outside around 7pm, the pair will be located towards the south west.

The Moon will be easy to spot, but Uranus currently has a magnitude of +5.8 so it is right on the limit of what could theoretically be seen with the naked eye if you were in a very dark sky location.  Bearing in mind that many observers will be in town with street lights and the Moon will be creating some light pollution of its own - a telescope will be required.  An aperture of at least 150mm is recommended, but what does that mean?
In layman's terms, it refers to the diameter of the hole in the front of the telescope and therefore the size of its lens or mirror.  The main job of an astronomical telescope is to collect as much light as possible from faint objects, so the bigger the hole, the more light it can collect!
Once the light has been collected, then an eyepiece is chosen to provide the desired magnification, but the more something is magnified, the dimmer it gets and often, lower magnifications are better.  A magnification of 200x is required to be able to see Uranus as a disc rather than just a blob with a greenish hue!
The following evening, Tuesday 8th, gives you an opportunity to observe the clair-obscur effects known as the Lunar X and V.  The Moon will be located towards the south just as it gets dark around 6pm and at that time, the terminator where sunlight hits the lunar surface, will illuminate the effects.



Monday 31st January to Sunday 6th February 2022
Tuesday 1st is a New Moon, so you could go outside the following evening and try to spot what will be a thin 3%-lit crescent.  At the same time, planet Jupiter will be just above it.  Look towards the south west around 5.30pm and you will be able to catch them just before they set below the horizon.

The Moon and larger planets appear bright because they are reflecting light from our Sun and in astronomical terms, the distances involved are very small.  Stars are always fainter because they are generating their own light and it is having to travel a long way to reach us.  You can easily see Jupiter and the Moon, but as it won't be properly dark at that time, you won't see anything else!

As the Moon orbits around us, it has a slight rocking motion; or if you like, it wobbles a bit.  The technical term for this is "libration".  It means that sometimes you can see a little further around the sides of the Moon that are normally facing away from us.
Animation courtesy of Wikipedia
On Sunday 6th, there is an opportunity to observe what are known as the "libration Seas" on the eastern edge of the lunar surface - Mare Smythii and Mare Marginis.  Just after dark, the Moon will be located towards the south and it will still be appearing as a crescent shape as we had the New Moon only a few days before.  The easiest way to spot them is to first locate the Mare Crisium that is slightly further around the nearside.

While you are looking at the Moon that evening, the Pleiades open cluster of stars will be above it and slightly to the left, with the constellation of Orion further left.