ORION TELESCOPES & BINOCULARS 9978 Instruction Manual

INSTRUCTION MANUAL

Orion® Premium 190mm

f/5.3 Maksutov-Newtonian

Astrograph

#9978

Customer Support [phone] • E-mail: [e-mail]

Corporate Offices [phone] • 89 Hangar Way, Watsonville, CA 95076

Providing Exceptional Consumer Optical Products Since 1975

OrionTelescopes.com

IN 370 7/09

Corrector
lens

Finder scope
dovetail base

Dual-Speed
Focuser

Primary
mirror cell

Figure 1.

The Premium 190mm f/5.3 Maksutov-Newtonian Astrograph optical tube assembly.

Congratulations on your purchase of an Orion®
Premium 190mm f/5.3 Maksutov-Newtonian
Astrograph. Your 190mm Mak-Newt Astrograph is

designed to deliver a flat field across the field of
view of an APS (advanced photo system) size cam-

™

era sensor, such as the StarShoot

Pro or DSLR
imager. Coma is reduced considerably when com­pared to a Newtonian of equivalent focal length.
The exceptional optical and mechanical quality
of your 190mm Mak-Newt will provide you with a
pleasing telescope experience. The optics are rig­idly secured in place to reduce image shift; and dif­fraction is minimal because the secondary mirror is
held by the corrector glass, eliminating the need for
spider vanes.

Parts List

Optical Tube Assembly

Optical tube dust cover

1.25" eyepiece adapter

Camera adapter

2.5mm hex key

Phillips screwdriver

Collimation cap

Getting Started

Your 190mm Mak-Newt arrives fully assembled from the fac­tory. The optics have been collimated, however you should
check the telescope collimation to ensure the collimation held
after it was shipped to you (see “Collimation”).

We recommend keeping all of the original packaging. In the
unlikely event you should need to ship the telescope back to
Orion for warranty repair service, you should use the original
packaging to ensure the telescope stays intact during shipping.
Take a moment to inspect the telescope and all of its parts.

Using 1.25" and 2" Accessories

Your 190mm Mak-Newt can accommodate both 1.25" and
2" accessories, including just about any eyepiece or camera.
The Crayford focuser has a 2" eyepiece holder with a 1.25"
eyepiece adapter installed. Both the 2" eyepiece holder and

1.25" eyepiece adapter feature a brass compression ring to
hold your accessories in place. The brass compression ring
securely holds the 1.25" or 2" accessory in place without
marking up its metal barrel.

Dual-Speed Crayford Focuser

The 190mm Mak-Newt features a heavy-duty dual speed
Crayford focuser, designed to handle the weight of your
eyepieces and imaging systems. The Crayford design offers
smooth and gradual motion, free of image shift. If the draw­tube slips under the weight of your equipment, simply increase
the focus tension by tightening the focus tension setscrew
(Figure 2).

Crayford focusers generally perform better than rack-and-pin­ion models because the design eliminates “focus shift”. Focus
shift is when an image moves position in the eyepiece when
it is being focused. This is very hard to eliminate in rack-and­pinion focusers due to slight gear and tolerance imperfections
which cause the drawtube to move slightly left or right when
focusing. For the Crayford design, the drawtube is constantly
tensioned (by the focusing shaft and four “roller bearings”)
so the drawtube cannot move perpendicular to the desired
motion.

The focuser provides the most focus range for accessories
that require extra in-travel. With a minimum focus height of
58mm, this focuser is an excellent choice for any astro-imag-

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Focus tension
set screw

Thumbscrew lock

Focus lock
thumbscrew

Figure 2. Use the focus tension setscrew to adjust the weight

capacity of the focuser. Tighten the focus lock thumbscrew to lock
the focuser in place.

ing system. The strong machined aluminum construction sup­ports heavy 2" eyepieces as well as heavy camera bodies.
The smooth focus motion and fine-focus wheel allow preci­sion adjustments for critical focusing of eyepieces and cam­eras. Once you have reached focus, you can lock the focuser
in place by tightening the focus lock setscrew (Figure 2).

Fine Focus

The focuser features dual speed adjustment with the fine
focus wheel. This small black wheel located on the side of the
right-hand focus wheel allows precise focus adjustment at a
ratio of 10:1, meaning one turn of the focus wheel equals ten
turns of the fine focus wheel.

Use the focus wheels to achieve rough focus on your target
object, then use the fine focus wheel to coax out even more
detail. You’ll be amazed at the amount of detail fine focus
adjustments allow you to view on targets such as the lunar sur­face, planets, double stars, as well as other celestial objects.
Alternatively, this focuser is also compatible with the Orion
AccuFocus when used with the Dual Speed Bracket (#5049).

Finder Scope Compatibility

The included finder scope dovetail base on the 190mm Mak­Newt is ready to accept any Orion finder scope.

To insert the finder scope onto your 190mm Mak-Newt, slide
the finder scope bracket into the finder scope dovetail base and
secure it in place by tightening the thumbscrew lock (Figure 3).

Operating the 190mm
Mak-Newt

Your 190mm Mak-Newt is suitable for both visual use and
imaging. We recommend using high quality eyepieces to
take full advantage of the 190mm Mak-Newt’s optical quality.
For imaging applications, the telescope is optimized for use

Figure 3. Slide the finder scope bracket into the finder scope

dovetail base and secure it in place by tightening the thumbscrew
lock.

Thumbscrews

Figure 4a. Remove the

cover plate on the primary
mirror cell by unthreading the
two thumbscrews that secure it.

Figure 4b. Four tapped

holes are provided for an
optional attachment of a
cooling accelerator fan.

with an APS size sensor, such as the Orion StarShoot™ Pro
or a DSLR camera.

Cooling the Telescope

All optical instruments need time to reach “thermal equil­ibrium”. The bigger the instrument and the larger the tempera­ture change, the more time is needed. Allow at least 30 min­utes for your telescope to cool to the temperature outdoors. In
very cold climates (below freezing), it is essential to store the
telescope as cold as possible. If it has to adjust to more than
a 40°F temperature change, allow at least one hour. You can
use the telescope while it’s cooling down, just note that you
may see “tube currents” which interfere with the telescope’s
ability to resolve a sharp image. Tube currents are essential­ly heat waves exiting both the optical components (such as
the primary mirror) and the telescope itself. The effect seen
through the eyepiece is much like looking above a hot surface
or fire.

The 190mm Mak-Newt primary mirror cell is compatible with an
optional cooling accelerator fan (available from Orion). Using
the fan significantly decreases the amount of time required for
the telescope to reach thermal equilibrium. Remove the cover
plate on the back of the primary mirror cell (Figures 4a and 4b)

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