For those unfamiliar with a planisphere, it is simply a small circular star chart made in order to enhance an astronomer’s viewing experiences by helping them locate areas of interest throughout the universe. For those who do not have extensive knowledge of the major constellations or where the brightest stars can be found, a planisphere helps them identify where celestial objects are compared to one another. It also allows both amateurs and experts alike to quickly ascertain what angle and location within the sky they should be viewing to spot each object in question, which saves vast amounts of time when comparing multiple star systems at once.
Some of the features to look for on a planisphere are the quality of the object itself and how much detail it provides. Some relatively inexpensive models may only point out the major star constellations, while some of the more elaborate ones may also include major nebulas and other astronomical areas of interest. Other uses included within some planispheres are to calculate future astrological events, a means to determine the sunrise and sunset for the particular area in question, and a numeric system to tell where a constellation or other celestial object will be located at any time during the day or evening. While most models of planispheres are made of a high quality plastic that should hold up for several years at a time, others are not as sturdy and will easily tear or crack. There are also various sizes available with a nominal difference in cost, so make sure to review those options as well.
Of course, dependent on where you live will decide which planisphere version needs to be purchased for your own personal use. They are each individually designed for specified latitudes; which means if one is purchased for viewing in Florida it would not be completely accurate when visiting Seattle. Since each location would have a different relative viewpoint of the sky it is necessary to produce several types of planispheres for each individual region so pinpoint information can be provided. Most companies have multiple latitudes available for each type of planisphere they carry, so make sure to verify that you are receiving the correct one (especially when ordering by phone or online).
The average price for a planisphere in a reputable store should be around $7-$12, with the deluxe models costing close to $20 or maybe even a little more. Of course in every hobby there are items meant more for the serious collectors within the profession, and astrology and planispheres are absolutely no different. There are a few reputable companies that produce fine planisphere watches that function much like their plastic counterparts, and since the time and date are already known by the timepiece the constellations are always accurate (provided you are at the correct latitude). Likewise, for the serious collector there are also fine items like planisphere coins and other collectibles. Of course, the largest and most dynamic planisphere of all is the one above us within the night sky, so be sure to use it often and enjoy the spectacular views.