The Night Sky August 2018
Lovely, long summer days mean hardly any real darkness, for me quite a dilemma! I am sure you don’t need to be told that during this month there is only true night darkness of 3 to 4 hours ‘astronomical twilight’. Not to worry though, as we can focus on remarkably bright objects that can be seen even without total darkness or a telescope.
Perseid Meteor Shower.
If you had no luck spotting meteors earlier this year then 11-12 August is a period to circle in your diary. This is the best time to observe the annual Perseid meteor shower, one of the best of the year. Also, it coincides with a new moon and that doesn’t happen very often! This shower can have a rate of up to 100 per hour and sometimes more. This is when the Earth passes through the debris of the great comet of 1862 known as Comet 109P/Swift-Tuttle. Looking roughly North East and half way up in the sky you find the ‘radiant’, where they will appear to originate. Follow my instructions from the April issue to help you enjoy, relax and spot meteors.
The Summer Triangle
This is a pattern that is created by 3 stars in the summer evenings. Deneb, Vega and Altair. It can be seen even in our light nights. It is important to bear in mind that this is a large pattern but easy to spot as they are almost the first stars to shine through as most are too dim at this time of year. Deneb is a huge star at least 100 times that our own sun and is famous for being the most rapidly rotating star known. Vega is one of the closest stars to our solar system and Altair also spins so quickly that it bulges out and is flattened at the poles. There are quite a few wonderful deep sky objects near or within the triangle. I’ve just picked out two that I photographed recently. If you get chance to spot the Ring Nebulae (M57) through a telescope it is very odd. Instead of seeing a bright point of light, a very distinct ring appears and it seems so out of place. After observing for a few seconds the wonderful colours of the ring emerge . This is the result of a dying star that has used up all of its fuel and has ejected its gas and dust surrounding it into space. Another unusual object to observe is the Dumbbell Nebula (M27). Through binoculars you will see a disc shape but with a telescope an hour-glass shape comes into view, again not what you expect to see! At the centre of it is a star (a white dwarf.) Research has speculated that the Nebula was created nearly 10,000 years ago, a relative youngster in astronomical terms!
Planets
Again there is quite a feast of planets to observe this month so here are a few pointers as to where and when to find Venus, Mars, Saturn and Jupiter.
Venus and Jupiter can be seen low in the south-west in the middle of the month.
Saturn low in the south between 20-21st
Mars low in the south-east around the 23rd
The Full Moon is on 26th
Adapting to the Darkness when it returns!
Giving yours eyes time to adapt to darkness is important if you want to see faint objects in the night sky. You may remember from school that our eyes contain light sensitive cells called rods and cones. Cones are what we use mainly during the daytime to see colour and brightness. When you first go into a dark environment the cones start to become more sensitive but after 10 minutes they are as sensitive as they are going to be. However, the rods continue to become more sensitive and reach their maximum in half an hour. A sudden bright light can spoil the sensitivity of both and you will have to get them used to the dark again. But by using a dim red your dark adapted vision remains intact.
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