Street Maps to the Stars

Probably the single most useful aid in orientation of the sky is The Planisphere or Star Wheel. By aligning hours, minutes and months on the outer rim we can view what constellations are up at any time on any given map. We can also do the reverse: rotate the wheel until a constellation is well placed and then read off the best times of the night or the year for viewing. We can also see at the glance the order in which the brightest stars rise and set. So starting in mid-December after dark we can see that looking south the rising order of the brightest stars are: Sirius and Canopus, Procyon, Alphard, Spica, Antares, Altair, Achernar, and Fomalhaut.

While everyone has a preference for their own mapping system it is always best to choose one you are comfortable and competent with. Test it outside where you will constantly use it to locate faint objects. Are you happy to write notes on it or maybe just take out photocopied sheets? Some maps and atlases do not respond well to red lights or to failing eyesight or can be too cluttered for the beginner. Beginners have a preference for pages that display at least one or two constellations, making orientation easier. Some just use computer maps, which can be drawn to scale and correct orientation. Before you buy, ask experienced users what system they like and why.

Many simple star charts are orientated for viewers in the northern hemisphere so be careful to correctly orientate your maps for your location and allow for the reverse polarity that a telescope view can cause. (I have wasted much valuable viewing time expecting a faint object to be NE of a star or group, only to find it is really SW). No matter what your experience, it is always important to return to naked-eye or binocular viewing of the sky from time to time to reacquaint yourself with the constellations. Even for the experienced astronomer this can bring a lot of pleasure – especially where cold weather demands ten-minute sky bites.