Apertura Dobsonian Telescope, Owner'S Manual

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Aligning Your Finderscope
When first attached, the finderscope will not be perfectly aligned with the telescope’s optics. Once the
finderscope is properly aligned with the main telescope’s view, the finderscope’s extra-wide field of view will
help you easily center the main telescope on objects you wish to view.

Start by inserting the large 30mm eyepiece into the telescope’s focuser. Point the telescope at a large,
distant and stationary object (such as the detail on a billboard at least 250 yards away). Focus the eyepiece and
center that distant object in the eyepiece; in other words, start with an earthbound object for focusing and
alignment. If you are not able to achieve good focus, you may need to insert the included 35mm Extension Tube
into the focuser and then insert the 30mm eyepiece into the extension tube. The 35mm Extension Tube is used
with low-power eyepieces to extend the focal length, making it possible to focus at low magnification.

Now look through the finderscope. To focus the finderscope, first loosen the lens cell by unscrewing it a
half-turn. Then turn the locking ring the other way, to pull it back from the lens cell and expose the maximum
number of threads on the finderscope body. Turn the lens back and forth to focus your view. Once the lens is
focused, then tighten the locking ring to hold the lens cell in place. You may need to make a slight focus
adjustment the first time you use the finderscope on the night sky, but once the focus is set on the sky you
should not need to adjust it again.

Once focused, then align your finderscope by gently
adjusting the two thumbscrews on the finderscope bracket (the silver “knob” contains a spring that gives back-
pressure to the thumbscrews and does not need adjustment). Carefully align the finderscope body until its
crosshairs are centered on the object that is currently centered in the main telescope’s eyepiece.

If you bump the finderscope during transport or use and disturb its alignment, it will only require a quick and
easy adjustment of the two thumbscrews to realign the finderscope to the main telescope’s view.
Finderscope Locking Ring
Finderscope Lens Cell
Alignment Screws
(black Nylon)
Spring Tensioner
(no adjustment)