Celestar Manual
Telescope Basics
26
3.
Adjust the wedge in altitude until the latitude indicator points to the latitude of the site from which you
are observing.
4.
Insert a low power eyepiece (i.e., one with a long focal length 25mm) into the telescope to give you
the widest field possible.
5.
Turn the clock drive on.
6.
Loosen 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.
7.
Locate the object in the finder, center it, and then look through the telescope.
8.
Turn the focus knob until the image is sharp.
9.
Take your time and study your subject. If observing the Moon, look for small details in the craters.
That’s all there is to using your Celestar telescope. However, do not limit your view of an object to a
single eyepiece. If you purchase other eyepieces of varying focal lengths, you can view at different
magnifications.
NOTE: If not using the clock drive, the stars will appear to drift out of the field of view. This is due to the
Earth’s rotation. In fact, any celestial object, day or night, will drift out of the field unless the
telescope has been polar aligned and the clock drive is running. More on this in the section on
“Polar Alignment.”
CALCULATING MAGNIFICATION
You can change the power of your Celestron telescope just by changing the eyepiece (ocular). To
determine the magnification of your Celestron telescope, simply divide the focal length of the telescope by
the focal length of the eyepiece used. In equation format, the formula looks like this:
Focal Length of Telescope
Magnification =
Focal Length of Eyepiece
Let’s say, for example, that you are using a 25mm eyepiece. To determine the magnification you simply
divide the focal length of your Celestron Telescope (let us use the Celestar telescope which has a focal
length of 2032mm) by the focal length of the eyepieces (25mm for the Celestar 8 and 26mm for the
Celestar Deluxe). Dividing 2032 by 25 yields a magnification of 81 power. A 26mm Pl
ö
ssl yields a
magnification of 78 power with the Celestar telescope.
Although the power is variable, each instrument under average skies has a limit to the highest useful
magnification. The general rule is that 60 power can be used for every inch of aperture. For example, the
Celestar telescope is 8" in diameter. Multiplying 8 by 60 gives a maximum useful magnification of 480
power. Although this is the maximum useful magnification, most observing is done in the range of 20 to
35 power for every inch of aperture which is 160 to 280 times for the Celestar telescope.
