Sky Watch 7 : 29th May - A tough challenge this week! Are you up for it!!

Just a couple of times a year, Mercury is visible and the planet is a special one to see. So your challenge this week is to see Mercury. One amazing night for viewing some years back, I went out with a good friend and we saw Mercury. We stayed viewing in our Herefordshire garden until after midnight and we managed to see Pluto - which at that time was still classified as a planet. So we saw the nearest and furthest planet in our solar system on the same night!

You know the constellations that are needed to star/planet hop - Gemini and Auriga. If you have just started looking with us, check back to earlier Sky Watch posts. Please note the time shown on the display below - it is important. Go out 15 minutes later and you will not see Mercury because it will have followed the sun down below the horizon. Please wait until the sun has gone below the horizon - THIS IS A VERY IMPORTANT SAFETY POINT. You will need a pair of binoculars and this means there is no chance of catching sunlight that would damage your eyes. Armed with your binoculars, you will need to go to a place where you can see a distant western horizon where there are no trees, buildings or hills in the way. Make sure you are in position around 10pm - so still quite light in the west. Check for the stars Castor and Pollux of Gemini and Capella from Auriga - these brighter stars will show up (the other stars of the constellation may not be seen until it has gone dark, but by that time Mercury will have disappeared below the horizon).

If you see brightness in the sky where the Sun is below the horizon, that is the area that you will need to observe. Stand and hold your outstretched arm with your thumb up and your finger lined up on the horizon as shown above. Mercury will never rise above the tip of your thumb - so the area near to the horizon that you have to search is relatively small. Focus your binoculars on a distant object and then scan the sky left and then right near to the horizon. Mercury is very faint and if you have never seen the planet before you might take a while to spot it. Be patient. Maybe the light from the Sun is still too bright at sunset - so give it 5 minutes for the Sun to go down some more. When you see Mercury for the first time, like me, you may call out and think why did I miss that! When Mercury appears in your binocular view, take the binoculars away and see if you can spot the planet with your naked eye - it will be very faint. Look again in steady binoculars (rest them against a tree or other solid object) and see if you can detect the phase and the size of the planet. Then, if you view on following days, note how the phase and the size of Mercury changes.

If you miss going out to see Mercury on Friday night, never mind, it will be around for about a week before it then starts to get back in line with the sun again and be lost from view.

If you do manage to see Mercury, you will have seen a very special space object.

FULL DETAILS OF HOW TO VIEW MERCURY ARE GIVEN IN OUR STARLEARNER VIEWING GUIDES