I will keep my Planisphere clean
I will keep my Planisphere flat and dry
Without me my planisphere is useless
Without my planisphere...
I will use my
Barnes and Noble had a nice big one.
At the time I had no idea that there were several "makes" and "models" available. Some have more navigational helps and some show more stars and some show more deep space objects to target. Most of them have at least the brightest
Mine is for the northern hemisphere and covers 30°to 60° north. The only declention markings are at 40°and 45°. There are hour angle markings every three hours, but I have made additional reference for every hour by marking the clear overlay with a fine permanent marker.
The planisphere maps out the brightest star members in each constellation in a way that I can recognize when I hold it in the proper orientation to the sky. It is the reference to this orientation of the constellations, their member stars, and the target objects that is of advantage to me. It has been one of my tools for learning the night sky
One simply lines up the outer edge of the planisphere so that the local hour aligns with the local month and day. Presto...a "cliff notes" glimpse of the present sky comes into view in the oval window of your planisphere. If you see a star that does not show up on your planisphere along the ecliptic it may well be a planet.
In the flat projection of the planisphere the rotation of the earth relative to the celestial bodies is represented. It appears to represent a sphere of stars rotating around Polaris. But as the disc is rotated it is actually representing the motion of earth longitude which gives the apparent 15° per hour western motion of the celestial objects.
Get a planisphere and play with it for a couple of hours under a stary night. They are not expensive and they require no batteries. You will smile when it all dawns on you.
Yes, the planisphere is limited, but in my opinion this limitation makes it a quick and powerful tool.
Although by now I have several star atlases I continue to use a planisphere with guests and from time to time on my own when the sky is obscuring and I cannot readily see my familiar navigational landmarks.
With the phone apps the planisphere might not be as popular, but I still think it is an economical and convenient way to get into navigating the night sky.
Peace, and clear skies to all.
