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Setting Circles are dials (or gauges) for right ascension and declination that allow you to locate celestial objects
easily from their coordinates as listed in a star chart or atlas.
1. The declination setting circle (see Figure 9) is scaled in degrees and the right ascension setting circle is
incremented in minutes. The circles will get you close to your target but not directly on it. Also, the accuracy of
your polar alignment will affect how accurate your setting circles read.
2. The declination setting circle is factory set and should not need any adjustment if it reads accurately.
3. The right ascension setting circle must be aligned. Choose a bright and easy to find star in a star chart and note
the coordinates (right ascension and declination). Find the star in the Star Pointer and then in the telescope.
Now, rotate the right ascension circle to match the coordinates of the star with the indicator mark. If you polar
aligned the telescope accurately, the declination circle should be correctly set to the proper coordinates.
4. The right ascension setting circle does not move as the telescope moves in right ascension and thus it must by
aligned each time you want to use it to find a new object. However, you do not need to use a bright star each time
but you can use the object you are currently observing.
5. Now, using a star chart or atlas you can find numerous objects. First move the telescope in declination to the
correct declination coordinate. Then move the telescope in right ascension until the indicator points to the correct
coordinate.
6. After moving the telescope to the correct celestial coordinates, look through the lower power eyepiece to see if
you have located the object you wish to view. Center the object in eyepiece. If the object is not visible in the
eyepiece, gradually pan the telescope, using the right ascension and declination cables, until the object is visible.
Always start by using your lowest power eyepiece (20mm) then switching to higher power once you have found
the desired object.
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The magnification (or power) of a telescope varies depending upon the focal length of the eyepiece being used and the
focal length of the telescope.
The PowerSeeker 127 telescope has a focal length of 1000mm and comes with a 20mm 1¼" eyepiece. To calculate
magnification, use the following formula, in which FL = focal length:
Therefore, if you use the 20mm eyepiece your magnification is 1000/20 = 50x. The same formula can be applied to
any of your eyepieces.
Important!
Magnification through any telescope has its limits. These limits are determined by the laws of optics and the nature of
the human eye. Most of your viewing will be done in the range of 50x to 130x. Higher powers are used mainly for
lunar and sometimes planetary observing where you can greatly enlarge the image and the atmospheric conditions are
near perfect. The images at extremely high powers magnify the image, but remember that the contrast will be very
low due to the high magnification. For the brightest images with the most contrast, start by using the lower power
eyepiece with a smaller image scale.
The following magnification levels can be achieved when using the standard eyepieces in conjunction with the 3x
Barlow lens:
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Magnification =
FL (telescope) in mm
FL (eyepiece) in mm
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