Meade LX10 Manual de usuario descargar pdf (Pagina 6)

4.3.4 How to Use a Planisphere

1. Note the d a t e and tim e (if the clocks are set for d aylight savings time, deduct an hour

from your clock tim e) .

2. On the sky wheel, tu r n the wheel unt i l it matches your time and date. The elliptical-

shaped opening shows t h e visible stars.

Figure 4.5: Finding Polaris

3. Find North. Hold the planisphere such that North is at the bottom. The hole in the

center marks t h e location of Polaris, the North star. (To ﬁnd Polaris in the sky at

night, ﬁrst l ocate the Big Dip per. The two stars at the end of the ‘spoon’ point to

Polaris. Refer to Figure 4.5.)

4. The planisphere is a projection of the night sky. Hold the pl a n i sp h er e up; it should

correspond to what the sky looks like. The stars directly overhead will be found in the

center of the map and those to t h e north will be at the bottom. The reverse side of

the planisphere shows the stars to t h e south. Always hold the pl an i sp h er e so that the

direction you are facing is at the bottom. Alternati vely, you may ﬁnd that it is easier

to use the chart wh en lying down.

Notice how the planisphere marks t h e celestial coordinates. Declination i s shown as a series

of concentric circles, with 90 being in the center. RA is sh own as a series of spokes, radiating

from the center. Recall how we can u se RA to determine at what time a star will be directly

overhead.

These small charts can be misleading in s everal r espects. This is not due to any ﬂaw in their

design; it is simply due to the fact that they are trying to capture a large hemisphere of the

sky and represent it on a small ﬂat circle. Firstly, the angular scale of objects in the sky is

much larger than on the map. The h ar d est part in usin g such a chart is making the transfer

from a small area on the map to a large are a on the sky. You can see the entire chart at

once but you cannot see the entire sky at once.

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Meade LX10 Manual de usuario Pagina 6