Celestron CR-150 HD instruction manual Nighttime Observing, Telescope Basics •

Nighttime Observing

Looking at objects in the sky is quite different than looking at objects on Earth. For one, many objects seen in the daytime are easy to see with the naked eye and can be located by using landmarks. In addition, objects on the ground are station- ary, at least for the most part. In the night sky you will see a tremendous amount of stars through the telescope that are not visible to the naked eye. One way to find objects (at least initially) is by using other stars to guide you there. This method of finding objects, known as star hopping, is very accurate. Yet it requires a fair amount of time to learn the stars well enough to guide you to other objects. In addition, the stars will appear to drift out of the field of view. This is due to the Earth’s rotation. In fact, anything in the sky, day or night, will drift out unless the telescope has been polar-aligned and an optional motor drive is running. There is more on this in the section on “Polar Alignment.”

1.Orient the telescope so that the equatorial mount is pointing north, as close to true north as possible. You can use a landmark that you know faces north to get you in the general direction.

2.Adjust the mount until the latitude indicator points to the latitude of your observing site.

3.Insert the eyepiece (low power) into the telescope to give you the widest field possible.

4.You are now ready to observe.

5.Release the right ascension and declination clamps and point the telescope at the desired target. The Moon or one of the brighter planets is an ideal first target.

6.Locate the object in the finder.

7.Lock the R.A. and DEC clamps to hold the telescope in place.

8.Center the object in the finder using the slow motion knobs.

9.Turn the focus knob until the image is sharp.

10.Take your time and study your subject. If looking at the Moon, look for small details in the craters.

That’s all there is to using your Celestron telescope. However, don’t limit your view of an object to a single eyepiece. After a few minutes, try using a different optional eyepiece, a more powerful one. This gives you an idea of how the field of view changes.

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