TELESCOPES & ASTRONOMY
BACKYARD VIEWING - GENERAL
|Preparation for observing will give you the best opportunities to see the most detail, colour and faintest of objects. The brightness of the objects you can see with your telescope depends on it's size. The size (aperture) of|
|a telescope determines it's||light gathering power.|
|It also determines what|
|magnitude||it can see.|
|Protection From Stray Light or Wind|
|If there are any lights or wind near your observing place, try too move around a corner, or put up a light block with material or plastic.|
|FAINT DEEP SKY|
Dark adapting your eyes to the night is the best way to be able to see fainter objects in more
detail. It takes around 20 minutes for your eyes to get use to
the dark. Unfortunately, it
only takes an exposure to a bright light for a fraction of a second to loose it. If the moon is
out when you observe, remember that
it looking at through the telescope will ruin your
dark eye adaption, so observe it first or last or use a moon filter.
Some people use a patch over one eye! Looks piratey, but it works for some people. The eye with the patch stays dark adapted.
If you are reading from charts, use a home-made or bought 'red light'.
|Looking through our atmosphere has a large effect on the objects we can see in the night sky. That's why it was important for astronomers to put a telescope outside our atmosphere in the Hubble Space Telescope. If you look at an object which is low on the horizon, it twinkles alot and may be broken up into different colours of the light spectrum when viewed through a telescope. This is because you are looking all the way across the Earth first, then through the atmosphere and into space. The Earth is giving off all sorts of heat and pollution which we must look through first. If you observe looking at an object straight up, then you don't have to look across the earth first, hence the better clarity of objects. It's a good idea to plan your viewing by looking at the objects when they are highest.|
|Mirror or Lens Expansion|
|Give your telescope time to change to the outside temperature. This take around 20 minutes for the average sized telescope. The temperature difference causes the glass of the mirror or lens to bend ever so slightly, but enough to cause image the to be fuzzy. Secondly looking through the heat haze rising off from a mirror (if the telescope has been brought from a hot indoors to cold outdoors) will not help the image clarity.|
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