Orion 9877 - Manual (Page 6)

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If you have trouble focusing, rotate the focus knob counter-
clockwise as far as it will go. Look through the eyepiece while
slowly rotating the focus knob clockwise. You should soon see
the point at which focus is reached.
Viewing with Eyeglasses
If you wear eyeglasses, you may able to keep them on while
you observe, if the eyepiece has enough “eye relief” to allow
you to see the whole field of view. You can try this by looking
through the eyepiece first with your glasses on, and then with
them off, and see if the glasses restrict the view to only a por-
tion of the full field. If they do, you can easily observe with
your glasses off by just re-focusing the telescope the needed
amount. If you suffer from severe astigmatism, however, you
may find images noticeably sharper with your glasses on.
Aligning the Finder Scope
The SkyView Pro 127mm EQ Deluxe comes with a 6x30
achromatic finder scope (Figure 3a). The number 6 means
six-times magnification and the 30 indicates a 30mm diame-
ter front lens. The finder scope makes it easier to locate the
subject you want to observe in the telescope, because the
finder scope has a much wider field of view.
The SkyView Pro 127mm EQ’s finder scope uses a spring-
loaded bracket that makes alignment of the finderscope very
easy. As you turn either of the thumbscrews, the spring in the
bracket’s tensioner moves in and out to keep the finder scope
secure in the bracket.
The finder scope must be aligned accurately with the tele-
scope for proper use. To align it, first aim the main telescope
at an object at least a 1/4 mile away—the top of a telephone
pole, a chimney, etc. First, loosen the R.A. and Dec. lock
levers and move the telescope until it is pointing towards the
desired object. Then sight along the tube to aim the tele-
scope. Turn the focus knob until the object is properly
focused. Make sure to position the object in the center of the
telescope’s eyepiece by turning the R.A. and declination slow-
motion control knobs (the R.A. and Dec. lock levers must be
tightened to use the slow-motion control knobs).
Now look in the finder scope. Is the object visible? Ideally it
will be somewhere in the field of view. If not, some coarse
adjustment to the finder scope bracket’s alignment thumb-
screws will be needed until the object comes into the finder
scope’s field of view.
With the image in the finder scope’s field of view, you now
need to fine-adjust the alignment thumbscrews to center the
object on the intersection of the crosshairs. Adjust the aim of
the finder scope by turning the thumbscrews, one at a time,
until the object is centered.
The finder scope alignment needs to be checked before every
observing session. This can easily be done at night, before
viewing through the telescope. Choose any bright star or
planet, center the object in telescope eyepiece, and then
adjust the finder scope bracket’s alignment thumbscrews until
the star or planet is centered on the finder’s crosshairs.
Focusing the finder scope
If, when you look through the finder scope, the images appear
somewhat out of focus, you will need to refocus the finder
scope for your eyes. Loosen the lock ring located behind the
objective lens cell on the body of the finder scope (see Figure
3a). Back the lock ring off by a few turns, for now. Refocus the
finder scope on a distant object by threading the objective
lens cell in or out of the finderscope body. Precise focusing
will be achieved by focusing the finder scope on a bright star.
Once the image appears sharp, retighten the locking ring
behind the objective lens cell. The finder scope’s focus should
not need to be adjusted again.
Magnification & Eyepieces
Magnification, or power, is determined by the focal length of
the telescope and the focal length of the eyepiece. Therefore,
by using eyepieces of different focal lengths, the resultant
magnification can be varied.
Magnification is calculated as follows:
Telescope Focal Length
= Magnification
Eyepiece Focal Length
The SkyView Pro 127mm EQ has a focal length of 1540mm,
which when used with the supplied 25mm eyepiece yields:
1540mm
= 62x
25mm
The magnification provided by the 10mm eyepiece is:
1540mm
= 154x
10mm
The maximum attainable magnification for a telescope is
directly related to how much light it can gather. The larger the
aperture, the more magnification is possible. In general a fig-
ure of 2x per millimeter of aperture is the maximum attainable
for most telescopes. Your SkyView Pro 127mm EQ has an
View through the SkyView Pro 127mm EQ
Figure 5. Images through the finder scope will appear
upside-down and backwards (rotated 180°). Images through the
SkyView Pro 127mm EQ with its diagonal in place will be reversed
from left-to right.
View through finder scope