About 300 nebulae, star clusters and galaxies are visible in binoculars, and also a variety of variables and double stars. Many of these objects are, however, on the edge of visibility or only visible in large binoculars under dark skies. Although it certainly has its appeal to test the limits of the performance of a binocular, the focus of the following selection is on better visible or particularly interesting objects. All should be visible with a 10 × 50, but in a smaller size binocular, some objects will be difficult or impossible to see. Do not forget that observing is a matter of practice and not all objects are striking – especially nebulae which can be very small or hardly stand out from the sky background, and planetary nebulae usually appear only as an un-sharp star. A tripod is recommended for the more challenging objects.
The star charts at the end of this book provide an overview of the area of the sky, which is best seen in the evening of each season. They are not confined to the area directly to the south, but also show the neighboring regions – the view of the sky changes over the course of the night, and it is quite interesting to know which constellations can be found just to the west or east. The star maps also show a few stars in the south that are not visible from middle latitudes – either because they are too low on the horizon and are swallowed by the horizon haze, or because they never rise above the horizon at all. This allows you to use the maps also in more southern regions. But selection of objects is so that observers in the Northern parts of the US (as well as central Europe) can see all of them – if you are farther to the south, you‘ll have it easier because they can rise higher and thus are better to see.
To get a quick overview about the constellations which are visible right now, take a look at a planisphere – you‘ll see at one glance the whole sky. Computer programs or apps also work and have their advantages, but don‘t give you such a quick overview.
For better orientation on the large scale star charts, you should make a stencil that shows the field of view of your binoculars. All charts are printed on the same scale. You can also download them as a PDF.
However, for the identification of weaker stars or for the observation of variable stars, you need better charts that are beyond the scope of this book. There are many celestial atlases available, and you can produce star charts on your own with a computer. Some recommended atlases and programs can be found at the end of the book under „Links and References“.