Thursday 19 December 2013

Viewing the sky

How do you view the sky in Shetland ? It may be that your eyes are good enough as there is less light and atmospheric pollution in the northern isles. Its amazing what you can see, stars, planets, comets and meteorites can all be seen, if you know where to look. That's the key to successful night watching - having a map of the sky is essential and a red light so after about 10 mins your eyes have adjusted to the dim viewing conditions.

This is all about the cones and rods in your eye. The rods are the ones to collect light in your eye, while the cones are for collecting colour. Therefore when looking at night try not to directly look at an object in the sky but slightly to one side where most of the rods are located. In night time mammals the rods are more common than cones as they need better vision in dark conditions.

Next move up to binoculars, either 10x50 or 8x40 these are great at gathering light. Don't bother with the high powered binoculars advertised in the newspaper , these 20x50 often at £25 rubbish. When I was about 12 years old i pestered my parents for a 20x50 binocular having been conned by the blurb and only used them twice to look at the moon, they gave a colour cast as well as a double image. Also don't forget that your arms will get tired very quickly and the will start to shake so you wont get very good views after a couple of mins even with a good pair.

And then you come to telescopes. Again its all about ensuring you get a good quality one,  you will be spending a few hundred pounds and  around £700+ for a Go-to scope which can find you subject without you needing to know which direction it is in. There are many good makes such as Meade & Celestron but go and have a look first. Its no good getting one so big you cannot lift it or get in the car
This is one of the biggest scopes in Sheffield, and even used by Aliens so you cannot ask for a better recommendation

You will also be an armchair sky watcher like everyone else as sometimes the weather is so bad you just cannot get outside to view. This is the time to be with your computer, working on some photos or researching for another perfect night

An armchair like this with a clear view of the sky

Is Father Christmas bringing you some extra equipment to make your Shetland sky watching even more pleasurable ? , I have sent him my list so I will let you know what happens after Christmas. Just one word of warning, when ever anyone gets some new equipment the weather turns worse so you cannot get out to use it- Sorry about that, so January is wiped out then !!

Tuesday 10 December 2013

Stars



Look up and you can see ..........................., well not very often but hopefully some stars. I know i have complained about the weather forecasts recently but will they ever get it right. Again prepared tom go out the other night only to find the weather had closed in an no stars visible, yet the weather forecast was still showing clear skies.

Well for me it makes every session more special, and yes you still have to cope with light pollution where we are and times when the moon is out reducing the dark skies with its torchlight. But when things come together I could stand looking up for hours, its so fascinating.

Now you may think all stars look white but when you take a closer look you see that some are Blue, Red and yellow. These colours are an indication of the surface temperature, just think of an iron bar heating up.First it glows red, then yellow then white hot.

White hot stars emit  at Blue and ultra violet wave lengths  so they appear Blue.




As the stars are so far way it doesn't matter whether you look through a powerful telescope or through a wide angle lens. They just appear as dots.
Don't forget the earth is moving so the stars need to be photographed within a few seconds, unless you want star trails ( I will cover the techniques in the next blog)

Our Milky Way is made up of 200 billion stars and is visible to the naked eye as a pale band across the sky. 
The brightness of a star depends on their true lumimosities and also distance from earth. A stars brightness is termed its apparent magnitude, or its true  brightness or absolute magnitude is defined as its magnitude at a distance of 32.6 light years away.

This may not mean alot to you but like all things I photograph i always like to know some information about the subject. One of the most important things about photographing the night sky is where on earth do you look?, well i mean where to look in the sky.You will need to start with a star chart and these are available on the internet, once you have these monthly charts its time to get outside and starting looking up. 

You will need to know which direction you are looking at then using your star chart you can plot you way around. When outside you would be best to use a red light as your eyes need to become accustom to the dark skies to have the maximum benefit. Start with the plough its one that most people know, you then can pick up Pole star and star hop to other interesting bits of the sky.