The Night Sky Planisphere

About The Night Sky Planisphere

My favorite device for finding objects in the night sky is the planisphere. I prefer this over a printed star map because it can be so easily adjusted for any time or date.

It's also a great way of determining how the sky changes during the course of the night and throughout the seasons.The Most common planisphere consists of 2 plates, a base plate which rotates and an outer horizon plate.

One of the most popular ones available and the one which I use frequently is The Night Sky Planisphere made by the David Chandler company. As you rotate the baseplate you will notice that where it revolves around the center is Polaris which is located near the North Celestial pole.

The rear side of the planisphere shows the southern sky and the center represents the South Celestial Pole. Around the outside edge are the months, days and the time of day so it is very easy to see what the sky looks like at any given date.

You can determine the date and time when any objects rise by rotating the base plate until the object comes into view in the east and when it sets by rotating the base plate until the object is over the horizon in the west, by just reading the time next to the date.

For daylight saving time you need to subtract one hour. The larger dots on the planisphere represent brighter stars which should be located first. The irregular shaded area seen represents the Milky Way which is visible only on clear dark nights.

Planets move along the eliptic and look like very bright stars, they are not shown on the planisphere because they move across the sky independently of the stars.

The planisphere comes in incremental versions to accommodate various bandwidths of latitudes from which to use them. For northern latitudes they are most commonly offered in 20/30, 30/40, 40/50 and 50/60 degree versions.

The Night Sky "30-40" matches latitudes from 30 to 40 degrees North, i.e.: - the mid-southern United States. You should select the one that supports your specific latitude.

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