A must have for any beginner amateur, it gives a list of objects with descriptions, information on how to find them and what to expect. I used to use it in the days of 4.
I think it is the best first book for a starting astro amateur. Astronomers' Observing Guides - a very good series mixing popular science and observing guide. Each book gives a solid and up-to-date overview of current understanding of the objects discussed, followed by tips and techniques for amateur astronomer observing session and finished with actual observing lists. The lists usually contain fine examples from all variations of the objects discussed, some overlooked in many other observing guides. For me it is very important to understand what I am seeing, so this series is highly recommended!
First part discusses equipment and techniques from the point of view of sub urban observing, the second part presents observing lists. In the northern hemisphere you can see this by the fact that the star Polaris is always in the same place overhead due north. It also explains why our view of the constellations changes over the year. The weather is generally considered to be the biggest hindrance to astronomy. Surprisingly, though, even a clear night may not be the best time to go out and observe. But bad seeing produces turbulent, unstable telescope views of the Moon and shuddering, shaky.
The setting Sun appears to have a jagged edge because you see its light through a turbulent atmosphere. In the atmosphere, air at different temperatures is always moving around and mixing together. Sometimes there are very few moments of clarity. One of the best ways to see this distortion is to watch the Sun setting on a clear horizon. It will have a jagged appearance, thanks to the sunlight moving through layers of turbulent air. Concrete absorbs more heat from the Sun and radiates it out to the. The other factor that affects observing conditions is the transparency of the night — just how clear the sky is.
Poor transparency generally means the air is steady with good seeing, but dust and particles are sitting in the atmosphere because the air is still. These conditions are good for looking at the Moon and stars. A good way to think of it is to imagine a swimming pool with a penny coin on the bottom. Through completely still water with no currents, the coin looks still, crisp and clear. In this case the seeing is perfect and so is the transparency.
Atmospheric conditions have an impact on the faintness of the stars you can observe. Use the chart here to check the faintest stars you can see by looking at Ursa Minor on a very clear night to work out your limiting magnitude. This is the faintest star magnitude, or brightness, that you can see from your location — higher numbers mean fainter stars. Many astronomers use the Antoniadi Scale as a measure of what the atmosphere is up to.
I indicates the best conditions, while V describes the worst. I Perfect seeing, without any quiver of turbulence whatsoever. II Slight shimmers; moments of stillness last several seconds. III Average seeing; larger air tremors blur the view. IV Poor views, with constant troublesome undulations of the image.
V Bad views with severe undulations; so unstable that even quick sketches are out of the question. One of the biggest problems facing astronomers today is light pollution.
In the worst cases, this causes the night to take on an unearthly orange glow. From some places the effect of light pollution can be to virtually wash away any evidence that there is a wondrous vista lurking behind it. Add in a dollop of hazy weather and your viewing gets even worse, as the light gets bounced around even more. Not surprisingly, the worst places for light pollution are the major towns and cities. One light can be just as terrible as an entire city when it comes to observing. Wherever you are, the problem is getting worse as towns spread and people feel they need more protection for their homes.
With increasing light pollution, the grandeur of the night sky has gradually been eroded. As light pollution increases, the number of stars you can see decreases. This is all described by limiting magnitude — ie, what is the faintest star visible? The biggest casualty is the band of the Milky Way, the band of stars that stretches high across the autumn skies.
As more people now live in towns and cities, an increasing number of people have never seen the Milky Way. Needless to say, if you are hampered by light pollution, then you can always place your telescope carefully in the car and drive off to a dark site. Never fear — just take a look at our four tips that should help lessen the effects of light pollution.
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Here are four ways to reduce the effects of sky glow. Find a position that is hidden from the view of nearby street or security lights by moving closer to a fence or wall. Make sure your eyes are properly dark adapted before viewing.
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Improve your chances of seeing fainter magnitudes by making sure your eyes are fully darkadapted before you go outside. Get a red light torch ready and turn off house lights for at least 15 minutes. Reduce the glare by asking your neighbours to temporarily turn off their security lights.
Are you friendly with your neighbours? Grey areas boast no adverse effects and are prime locations for observing. You might think that the idea of actually stopping on an object for 15 minutes or so, especially to draw the thing or at least be able to describe it in detail, seems a little old-fashioned.
To fully appreciate the sky, there is nothing like an observing log — a journal in which you detail information, observations and thoughts during an observing session. But overall, by paying attention to and recording what you are looking at, your observing improves.
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By taking time, objects take on a new light, which adds a great deal to your experience. You may have seen wonderful observing logs from a dedicated few, and it might seem daunting to try and follow their example. Drawings are a bonus and can really enhance your logbook entry. Once you become a seasoned observer, you may not even need to do the full sketch at the telescope — just do a rough drawing and complete it indoors as soon as possible after the session is over. Indeed, many astronomers use a pocket notebook to jot down some records outside before transcribing observations into a nice hardback, A4-sized logbook.
The book keepers Observers keep logbooks for lots of different reasons. Here, one very famous astronomer and a keen amateur share some insights into what they keep them for and the best way to log your observations. Your log should show what you have observed and what you need to observe next. This can also be a help to other observers studying the same or similar objects.
In the late s, radio waves from Jupiter were detected. For me personally, keeping an observing log is about capturing memories of spectacular sky events and recording those events in your own style so that they can be relived with a smile at some point in the future. I record everything in the sky that is of interest to me. This includes. I was able to provide these details from my Jupiter logbook pictured above.
A logbook entry should include the objects you observed, the equipment. I also like to complement observations with details that may seem trivial to some but that I know will raise a smile when I re-read them myself. The antics of my cat often feature — like the time when it jumped on the telescope one night, causing it to swing frantically to the zenith. It is very useful to include illustrations. And never send away an original observation — always send a copy. For measuring the big distances to the stars, astronomers use something called parallax.
This is how it works in space, too, except our two views are six months apart, when Earth is on either side of its orbit around the Sun. Just like the technique for the Moon see p30 , it involves measuring the time it takes for a burst of radio waves to come back. Of course, Venus is farther away than the Moon: the lunar laser is back in three seconds, while the journey to Venus and back is four minutes.
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Stepping into the garden on one of those crisp clear nights, I see sparkling stars and a crescent Moon about to set near the western horizon. What is just as amazing is the fact that I cannot tell which of these objects is the closest or furthest away from me. Knowing that the star Aldebaran is over nine million times more distant than the Moon does not really compute anyway — these distances are too big for my brain. As far as locating objects in the sky is concerned, we project them onto an invisible great glass thing around us called the celestial sphere. But what if we are? We would use centimetres or inches to measure the length of a bookcase for astronomy books, of course , but that would not make any sense when trying to explain the distance from Glasgow to Belfast.
So kilometres or miles are our Earthly scale of things. Travelling out farther, the nearest star, Proxima Centauri, is around , AU away. Enter, stage right, the lightyear. This wonderful length is simply the distance that light travels in one year. Speeding along at almost , kilometres per second. With this unit at hand we can say that Proxima Centauri is 4.
Learn how to observe the sky in 10 easy steps
When we think about how light travels from a star that is, say, 80 lightyears away, we realise that we are seeing that star as it appeared 80 years ago. The light has been travelling through space for all that time before it ends up in our eyes; therefore, when we gaze into space what we are actually doing is looking back in time. Stars live for millions, if not billions, of years, so even a star that is 5, lightyears away in the night sky is still really shining away quite happily.
These mirrors have been used constantly ever since, and are now the longest working Apollo lunar experiments. The time it takes to get there and back gives you the distance to the Moon, if you know the speed of light.