Celestron CR-150 HD - Manual (Page 25)

Telescope Basics • 25
Nighttime Observing Nighttime Observing Nighttime Observing Nighttime Observing 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.