Generally speaking there is an all encompassing rule for getting the most out of your observations, whatever specific type of star you are observing, and that is the darker the better. Observing from the darkest sky possible will make subtly different shades of colour present in each star much more noticeable. Even in the most built up suburb though, the difference between the dazzling blue Rigel and the deep orange of Betelgeuse will be obvious even without the aid of optical equipment. In such bright skies though, the majority of the other stars visible will appear a uniform white across the sky. From rural locations far from the effects of sky glow each star will take on a different hue, especially when using binoculars or a telescope.
Darker locations will not only reveal colour in the stars but as your pupils begin to dilate and the receptors in your eyes known as rods and cones become more sensitive to distant light, you will notice a vast increase in the amount of stars you can detect. The eye usually takes between 10 to 30 minutes to become fully dark adapted.
Once a suitably dark site has been chosen it will be important to know which will be the best nights to observe, helping you to ensure you get the most out of your session and avoiding unnecessary disappointment. Ideal conditions occur on cold nights, the lower the humidity the better. Glancing up at the sky there is a fast and easy way to assess conditions, simply choose the brightest star you can find and watch it for a minute. The more fiercely it twinkles the more unfavourable the conditions. What you want is a steady star that seems to emit a constant stream of steady light. Pulsation or twinkling occurs when the Earth’s atmosphere is turbulent, making the fainter stars harder to see.
In this way absolutely anyone can get the most out of their observations. You may find that your passion drives you on to purchase a telescope to see fainter and more distant suns. For observing stars the best telescope is the refractor as it offers magnificent colour rendition over similarly priced alternative designs, such as the reflector.
It is always best to use high magnifications, achieved with an appropriate eyepiece, to view the stars. Higher magnifications have the effect of darkening the background relative to the star making it appear to stand out more dramatically from the surrounding sky. High magnification is also vital for separating close binary stars. These are stars that orbit each other closely, the component stars often differ in colour, highlighting their differences by their close proximity to one another.
For the really stellar obsessed there are now a variety of spectroscopic eyepiece filters available to the amateur astronomer. These specialist filters, separate any star viewed into it’s constituent colours rendering them subject to study. The differing light patterns created belie the chemical composition of the star, so by looking at the display of light it is possible to analyse what the star is made of. Far from being prohibitively expensive and complicated the filters are available for the same price as an averagely priced visual eyepiece and comes with everything you need to know to get started.
