A couple of weeks ago I mentioned the "phases" of Venus that you can see with a telescope.  Well the evening of Thursday 27th gives you an opportunity to observe the planet as a thin 15%-lit crescent.  Around 7pm, Venus will be easy to spot shining at a very bright magnitude of around -4.8 as it sets below the western horizon.

How about something a little more challenging?  The following evening, on Friday 28th, there is the chance to spot a very thin (less than) 1%-lit waxing crescent Moon.  At 6pm, the Moon will be just about to disappear below the western horizon.  Please be careful though, as this will only be about half an hour after the Sun has set and if you are tempted to use a telescope or binoculars to obtain a better view of the Moon, don't aim in that direction too early and accidentally catch a glimpse of the Sun itself!

If you are in an astronomical mood after finding the Moon, you could then hop in the car and come to the next of my talks and star parties at the Ham Hill Visitor Centre that starts at 7pm on Friday 28th.  To reserve places, please contact Lucy who is their Engagement Ranger on 07917 201611.

There a couple of excellent early morning opportunities to spot the International Space Station passing overhead like a bright star that is silently travelling across the sky.  Monday 24th at 5.39am and Wednesday 26th at 5.40am.  In both cases, the ISS will appear in the west and will be visible for about five minutes before it disappears towards the east.

The Engagement Ranger at Ham Hill, where I run some of my astronomy talks, asked me a question the other day and it prompted me for an interesting topic here.  She had seen a white ring around an almost-full Moon - a phenomenon known as a "Moonbow".

This is a rare occurrence where sunlight reflected from the lunar surface is refracted by water droplets as it passes through our atmosphere.  If the light is quite strong, you may even see the colours of the rainbow, just like a regular rainbow here on the Earth, although the Earth-based ones are much more obvious as the sunlight is coming direct from the Sun and so is far more intense.

White light, that originates from the Sun, is a combination of the three primary colours - red, green and blue.  If white light reflects off a surface (like a mirror) it stays as white light.  If white light passes through a lens or prism (or in this case, water droplets), then the different wavelengths of light or colours take slightly different paths and it has the effect of splitting up the colours - this is refraction.

The sky is blue during the day because white light coming from the Sun is scattered by tiny air molecules.  Blue light has a shorter wavelength than red, so the blue light is scattered more - hence the sky looks blue.  When the Sun is low in the sky at sunrise and sunset, its light has to travel further through our atmosphere and then the blue light gets scattered so much that the red light, which has a longer wavelength, can then pass through and be detected by your eyes.

Having mentioned Ham Hill at the start.....a reminder that my next astronomy talk and star party at their Visitor Centre is scheduled for the evening of Friday 28th February.  Please contact the Rangers Office on 07973 887129 to reserve a place.

At the moment, Venus is a spectacular sight in the early evening sky as it sets below the western horizon.  It is currently shining at a very bright magnitude of around -4.5 so easy to spot with the naked eye.  Because Venus is between us and the Sun, it is also possible to observe different phases, just like our Moon.  You need a telescope to be able to see the phases however.

Look towards the west south west at 7pm on Monday 10th to find Venus, with Saturn below and to the right of it, just about to disappear below the horizon.

Please don't be tempted to set-up your telescope too early though, as you mustn't risk catching an accidental glimpse of the setting Sun in the eyepiece.

We used to consider Venus to be our sister planet and possibly a refuge if we needed to abandon the Earth.  To ancient Greeks and Romans, Venus represented the goddess of love.  In reality, nothing could be further from the truth!

Venus has a very dense atmosphere comprised mainly of Carbon Dioxide with Sulphuric Acid clouds.  The thick atmosphere traps heat and the surface temperature is almost 500 degrees Celsius.  This "greenhouse effect" in turn causes high pressure some 92 times that of the Earth!  In other words, if you tried to land on Venus you would be suffocated, dissolved, cooked and squashed.....but not necessarily in that order!

Views in the eyepiece can be very deceiving sometimes!

At 10.45 pm on Wednesday 5th February, a 55%-lit waxing gibbous Moon will be located towards the west, with the Pleiades open cluster of stars and planet Jupiter above and to the left of it.

This is the optimum time to try and identify another of those clair-obscur visual effects on the lunar surface known as the "Stars of Aristillus".  The crater Aristillus is located towards the top of the Moon.  It is 55Km in diameter and prominent peaks in the centre of the crater's flat surface create the visual effect.

If you've brought your telescope out to see the Stars of Aristillus, at the same time, planet Uranus at a magnitude of only +5.7 will be located a little below and to the left of the Moon.

A few weeks ago I mentioned the Moon's libration or wobble.  On Thursday 6th, this wobble favours the south east part of the lunar surface where there is a cluster of dark lava-filled craters right on the edge of where you can see.

Around 7pm on 6th, the Moon will be found towards the south, above Jupiter and the constellation of Orion.  Look to the west and you should be able to catch Saturn and Venus setting below the horizon.

Go back outside again around 7pm on Sunday 9th and the Moon will be located towards the south east this time.  It will appear more gibbous now, with a greater percentage of the surface illuminated, as the Full Moon is only a few days away.  Mars will be very close to the Moon's south east limb and easy to spot with just the naked eye.

I haven't made much mention of deep sky objects recently - targets that are outside of our Solar System and much further away.  Well the evenings next week are an ideal opportunity to go hunting them as the Moon will be below the horizon and not causing any light pollution.

Look towards the south around 9pm any evening next week and the constellation of Orion will be easy to spot with Mars above and to the left of it.  Jupiter and the Pleiades open cluster of stars will be above and to the right of Orion.  At this point, the constellation will be at its highest in the night sky, so less atmospheric disturbance.

Let's focus our telescope on what is called the "sword" of Orion to find the Great Orion Nebula, also known as M42 in the Charles Messier catalogue.  You are looking for a faint fuzzy blob half way down the sword.

M42 is known as an "emission nebula" because its gas is very active and radiating its own light.  It is an area where new stars are born and is about 1600 light years away from us.

When you see a photograph of the nebula, it is always in glorious techni-colour and looks stunning.  This is because a camera soaks up light (a bit like a sponge) and the image will be heavily processed to highlight detail.  When using an eyepiece in real time, your eye only senses a little bit of light and cannot resolve colour at those low levels.

This is why the lack of Moon is important, as sunlight reflecting from the lunar surface spoils the contrast of deep sky objects in your eyepiece.

Because the Moon takes the same time to rotate on its axis as it does to orbit around us, we always see the same face and are never able to see what is called the "dark side".  However, our natural satellite exhibits something called "libration" which means it wobbles a bit and sometimes we can see a bit further around the surface than at other times.

A couple of weeks ago I mentioned the seas or "mare" on the lunar surface and the obvious Sea of Tranquility where Apollo 11 landed.  The Mare Orientale on the western limb of the Moon is much harder to spot, but on Saturday 25th, the Moon's libration tilts Mare Orientale and a crater near it called Grimaldi into a slightly more favourable position.  You will need to be up early though, to catch what will be a crescent Moon, rising above the south east horizon from 6am.

There are a number of excellent early evening opportunities to spot the International Space Station next week:

Monday 20th at 5.46pm

Tuesday 21st at 6.34pm

Wednesday 22nd at 5.45pm

Thursday 23rd at 6.33pm

Friday 24th at 5.45pm

At least one of those evenings has got to be clear surely!

You are looking for a bright pinpoint of light that appears towards the west and spends up to six minutes passing silently overhead, before disappearing to the east.

Finally, a reminder that my next astronomy talk and star party at the Ham Hill Visitor Centre is scheduled for 7pm on Friday 31st January.  To reserve places, please contact the Ham Hill Ranger's Office direct on 07973 887129.

If you look towards the south east at 7pm on Monday 13th, Jupiter will be an easy "naked eye" target, shining at an extremely bright magnitude of -2.6 and sitting above the constellation of Orion.

Whip your telescope out and there is an opportunity to see the shadow of Jupiter's moon Ganymede as it transits across the face of the planet.  The shadow should be visible until 9pm.  With even a modest telescope or binoculars, you should be able to observe all four of Jupiter's Galilean moons - Io, Europa, Ganymede and Callisto.

Sometimes you can't see all four moons at once because as they orbit around the planet, the moons are blocked from our view, but at 7pm on 13th they will all be visible.  At that point, you will actually be witnessing what Galileo saw in the 1700s, when he first realised that we orbit around the Sun along with the other planets in the Solar System.

When the transit of Ganymede's shadow has finished, look to the left of Jupiter and a Full Moon will be very close to planet Mars.  Mars will be easy to spot at a magnitude of -1.4 and it has an obvious red tint.

Of course, around the time of a Full Moon, its light pollution spoils the contrast of faint deep sky objects, so let's stick with our neighbours in the Solar System.

Look towards the south west around 7pm on Saturday 18th to see a magnitude -4.6 Venus close to a dimmer magnitude +1.1 Saturn as the pair set below the horizon.

On Monday 6th, a little after dark, there is an opportunity to see the clair-obscur visual effect known as the "Lunar X & V" on the Moon's surface.  At 6pm, a waxing quarter Moon will be located towards the south, with Venus and Saturn disappearing below the horizon to the south west, while Jupiter and the constellation of Orion will be found towards the south east.

Sunlight falling at particular angles on the Moon creates different visual effects at different times during its orbit around us and in the case of the "Lunar X & V" (that resemble the shape of those two letters in the alphabet) the effect can be seen on the terminator, which is the barrier between sunlight and darkness on the Moon's surface.  The "X & V" are only visible for a brief period at the time of a waxing quarter Moon and are caused by sunlight hitting the rim of certain craters.

You will need binoculars or a telescope to see the shapes, but beside the "V" is a dark, flat area called the Sea of Tranquility that can easily be spotted with the naked eye.  It is where Apollo 11 landed in 1969.

Early astronomers with basic telescopes used to think that because these areas were dark and flat, they must be oceans of water.  Of course we now know that not to be the case.  The Sea of Tranquility does have a slightly bluish tint however, which is thought to be due to a higher metallic content in its rocks - nothing to do with water at all!

Sticking with the lunar theme this week, if you go back outside around 9pm on Thursday 9th, an 81%-lit waxing gibbous Moon will be located towards the south, just to the left of the Pleiades open cluster of stars.

How about celebrating the beginning of the New Year with a simultaneous occultation and transit?  Sounds a bit like some sinister black magic ceremony, but we're actually talking about a couple of Jupiter's Galilean moons!

From 9.45pm on Thursday 2nd, Ganymede is occulted by the planet as this largest of Jupiter's moons orbits behind the gas giant and so is blocked from our view.  Ganymede reappears from behind Jupiter again at 11.50pm.  At the same time, Io begins to transit in front of the planet and about half an hour later, its shadow will be cast on the planet.

During the event, Jupiter will be very easy to spot, shining very brightly at a magnitude of around -2.7 and located towards the south, above the constellation of Orion.  Mars will be to the left of them, shining at magnitude -1.2 which is also pretty bright!

Of course, although the planets themselves are easy "naked eye" objects, you will need a telescope to be able to see Jupiter's moons doing their thing!  Our Solar System neighbours always look bright because they are relatively close to us and you can only see them because sunlight reflects off the planets' surfaces.  Stars are fainter because they are much further away and radiating their own light.

The evening of Friday 3rd into the early morning hours of Saturday 4th sees the peak of the annual Quadrantids meteor shower.  At midnight, the radiant point, where the shooting stars appear to originate from, will be located towards the north east.