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Meade Model 230 Refracting Telescope Instruction Manual
 Model 230 60mm (2.4") Altazimuth Refracting Telescope
IMPORTANT NOTICE! Never use a telescope or spotting scope to look at the Sun! Observing the Sun, even for the shortest fraction of a second, will cause irreversible damage to your eye as well as physical damage to the telescope or spotting scope itself.

[ toc ] Introduction

This manual details the set-up, operation, specifications and optional accessories of the Model 230 Altazimuth Refracting Telescope. The Model 230 is an easy to operate, high performance telescope designed for both astronomical and terrestrial observing. In order that you may achieve maximum utilization of the instrument, we urge that you take a few minutes to read all of this manual before making first observations through the telescope. As you read through this manual, the technical terms associated with telescopes will be made clear.

Figure 1: Model 230 60mm (2.4") Altazimuth Refracting Telescope
1. Eyepiece
2. Viewfinder
3. Viewfinder collimation screws
4. Optical tube assembly
5. Vertical lock knobs
6. Horizontal lock knob
7. Tripod leg
8. Leg brace supports
9. Accessory tray
10. Tripod-to-mount base attachment point
11. Tripod attachment bolts
12. Accessory tray-to-leg brace wing nut hardware
13. Diagonal mirror
14. Objective lens cell
15. Focuser drawtube
16. Altitude rod slow motion fine adjustment control
17. Altitude rod coarse adjustment lock knob control
18. Altazimuth mount
19. Adjustable sliding center leg extension
20. Sliding leg extension thumbscrew-lock
21. Dew shield/lens shade
22. Front lens cap
23. Focusing knob
24. Viewfinder bracket

[ toc ] Standard Equipment

  • Complete optical tube assembly with 60mm diameter, multi-coated objective lens, dew shield, mounting hardware, 5 x 24 viewfinder with bracket, and rack-and-pinion focuser. Lens focal length = 700mm; f/11.7.
  • Altazimuth mount with continuously adjustable, aluminum tripod and leg braces.
  • MA25mm (28x) and MH9mm (78x) eyepieces (1.25" O.D. )
  • Hybrid diagonal mirror (fits into the telescope's .965" focuser, and accepts 1.25"- barrel diameter eyepieces)
  • Accessory tray
  • 3 bolts (3" long) with wing nuts and washers
  • 3 screws (1/2" long) with wing nuts and screwdriver tool
Note: All other necessary hardware provided in place.

[ toc ] Unpacking and Assembly

Note that although the telescope is unassembled, all of the more difficult or complicated sections of the instrument are already factory pre-assembled; first time assembly of the telescope should not require more than about 15 minutes. To set up the telescope, follow this procedure:

1. Remove and identify the telescope's components, using the listing above.

2. Attach the 3 aluminum tripod legs (7) to the base of the altazimuth mount (10) with the 3 hinged leg brace supports (8) facing inward. Three bolts (11), each about 3" long, with washers and wing nuts, are provided for this purpose in hardware package "A." Spread the tripod legs evenly apart so that the accessory tray can be positioned to attach to the 3 leg braces.

3. Attach the accessory tray (9) to the leg brace supports (8) with the 3 short screws and wing nuts (12) provided in hardware package "B." Place the accessory tray on top of one of the leg brace supports (8) of the tripod so that the mounting screw passes through the hole at one of the corners of the accessory tray (9), and through the hole at the end of the leg brace. Then thread-on and tighten the wing nut. Repeat this procedure until all 3 corners are mounted to the 3 leg braces.

4. Extend the sliding center portion of the adjustable height tripod leg (19) to the desired length for all 3 legs. Lock in place by tightening the leg lock thumbscrew (20).

5. Attach the viewfinder bracket (2) to the telescope using the 2 thumbscrews provided. These thumbscrews are pre-threaded into the main telescope tube at the viewfinder location. The thumbscrews fit through the 2 holes located at the base of the viewfinder bracket and thread into the main tube.

6. Insert the diagonal mirror (13) into the focuser drawtube (15) and the MA25mm eyepiece (1) into the diagonal mirror. Secure each in place with a moderate tightening of the respective thumbscrews.

7. The telescope is now completely assembled. To move the telescope and point it from one object to another, first slightly loosen one of the chrome-lock (star shaped) knobs (5) which serves as a vertical lock, then loosen the azimuth (horizontal) lock (6). Loosening these locks allows the telescope to be moved freely (vertically or horizontally) in any direction so that the telescope can be positioned to center a terrestrial or celestial object in the telescopic field.

[ toc ] ALIGNING THE VIEWFINDER

The wide field of view provided by the 5 x 24mm viewfinder permits easy object sighting prior to observation in the higher-power main telescope. To align the viewfinder, follow this procedure:

1. First, remove the front lens cap (22). Then using the lowest power (MA25mm) eyepiece placed in the diagonal mirror, as described in paragraph 6, point the main telescope at some well defined land target (e.g., the top of a telephone pole) at least 200 yards distant.

2. Look through the viewfinder (2) and tighten or loosen, as appropriate, the viewfinder's 6 collimation (alignment) screws (3) located on the viewfinder bracket (24), until the cross hairs of the viewfinder are precisely centered on the same object already centered in the main instrument's field of view. Hint: center the front of the viewfinder in the bracket using the 3 front ring thumbscrews, then make final object centering adjustments with the back ring 3 thumbscrews.

3. With this alignment accomplished, objects located first in the wide-field viewfinder will then be centered in the main telescope's field of view. Focusing the viewfinder's image is accomplished by turning the threaded eyepiece of the viewfinder. (Note: The viewfinder presents an image which is upside-down; this is customary in all astronomical viewfinders).

[ toc ] USING THE TELESCOPE

With the telescope assembled as described above, you are ready to begin observations.

1. First decide on an easy-to-find object. Land objects during the daytime are a good way to become accustomed to the functions and operations of the telescope. At night, try observing the Moon first, if it is visible, or a bright star.

2. To center an object in the main telescope, first use the aligned viewfinder to sight-in the object you wish to observe. If necessary, slightly loosen one vertical lock (5) and the altitude rod lock knob (17), to re-position the telescope so that the desired object can be centered in the viewfinder. When the object is centered in the viewfinder, it should then, also, be somewhere in the main telescope's field of view. Next, using the 25mm eyepiece, center the object in the main telescope's field of view, and sharply focus the image by turning the focus knob (23).

The 25mm eyepiece included as standard equipment is the best eyepiece to use for the initial finding and centering of an object. The low power 25mm eyepiece presents a bright, wide field of view, ideal for terrestrial and general astronomical observing of star fields, clusters of stars, nebulae, and galaxies. For lunar and planetary viewing, switch to a higher power eyepiece such as the MH9mm–conditions permitting. If the image starts to become fuzzy as magnification is increased–back down to a lower power–the atmosphere is not steady enough to support higher powers.

3. If you are observing an astronomical object (the Moon, a planet, star, etc.) you will immediately notice that the object is in a rather slow but continuous motion through the telescopic field of view. This motion is caused by the rotation of the Earth on its axis which results in an apparent motion of the object in the telescope's field of view; i.e. although the Moon, planets and stars are, for practical purposes, fixed in their positions during any 2 or 3 hour observing session, the platform on which the telescope is sitting (the Earth) rotates once every 24 hours underneath these fixed objects. To keep astronomical objects centered in the field, simply move the telescope on one or both of its axes (vertical and/or horizontal) as appropriate. At higher powers, astronomical objects will seem to move through the field more rapidly.

4. Avoid touching the eyepiece while observing through the telescope. Vibrations resulting from such contact will cause the image to move. Likewise, avoid observing sites where ground-based vibrations may resonate the tripod. Viewing from the upper floors of a building may also introduce image movement.

5. Allow a few minutes for your eyes to become "dark adapted" prior to attempting any serious observations. Use a red-filtered flashlight to protect your night vision when reading star maps, or inspecting components of the telescope.

6. Avoid setting up the telescope inside a room and observing through an open window (or worse yet, a closed window). Images viewed in such a manner may appear blurred or distorted due to temperature differences between inside and outside air. Also, it is a good idea to allow your telescope a chance to reach the ambient (surrounding) outside temperature before starting an observing session.

7. We repeat the warning stated at the outset of this manual:


NEVER POINT THE TELESCOPE DIRECTLY AT OR NEAR THE SUN AT ANY TIME! OBSERVING THE SUN, EVEN FOR THE SMALLEST FRACTION OF A SECOND, MAY RESULT IN INSTANT AND IRREVERSIBLE EYE DAMAGE, AS WELL AS PHYSICAL DAMAGE TO THE TELESCOPE ITSELF.

8. Certain atmospheric conditions can distort an observed image. Planets, in particular, viewed while low on the horizon often exhibit lack of sharpness–the same object when observed higher in the sky will appear to be much better resolved with far greater contrast. Also, turbulent air in the upper atmosphere can cause the images to "shimmer" in the eyepiece–reduce power until the image steadies. Keep in mind that a bright, clearly resolved, but smaller image will show far more interesting detail than a larger, dimmer, fuzzy image.

9. The Model 230 may be used for a lifetime of rewarding astronomical and terrestrial observing, but basic to your enjoyment of the telescope is a good understanding of the instrument. Read the above instructions carefully until you understand all of the telescope's parts and functions. One or two observing sessions will serve to clarify these points forever in your mind.

10. The number of fascinating objects visible through your Meade refractor is limited only by your own motivation. Astronomical software, or a good star atlas (e.g., the "Meade Star Chart") will assist you in locating many interesting celestial objects. These objects include:

  • Cloud belts across the surface of the planet Jupiter.
  • The 4 major moons of Jupiter, visible around the planet, changing position each night.
  • Saturn and its famous ring system.
  • The Moon: A veritable treasury of craters, mountain ranges and fault lines. The best contrast for viewing the Moon is during its crescent phase. The contrast during the full Moon phase is low due to the angle of illumination.
  • Deep-Space: Nebulae, galaxies, multiple star systems, star clusters–hundreds of such objects are visible through the Model 230.
  • Terrestrial objects: Your Meade telescope may also be used for high resolution land viewing. In this case, note that the diagonal mirror results in an image which is reversed left-for-right, but which is correctly oriented up-and-down. For a fully corrected image, the #931 45° Erect Image Hybrid Roof Prism (1.25" O.D.) is required. See OPTIONAL ACCESSORIES. Terrestrial observations should almost always be made using a low power eyepiece (50x or less) for bright, sharp images. Land objects will not normally accept higher powers well because the telescope is being pointed through the thickest part of the Earth's atmosphere, unlike astronomical observations made by pointing the telescope up and through a thinner atmosphere.

CALCULATING POWER

The power, or magnification, at which a telescope is operating is determined by two factors: the optical, or focal length of the telescope's main (objective) lens and the focal length of the eyepiece being used.

The focal length of the Model 230's objective lens is 700mm. To compute power, divide the focal length of the eyepiece into the focal length of the objective lens. The resulting quotient is the magnifying power of the telescope when used with the eyepiece in question. For example, the MA25mm eyepiece yields with the Model 230, a power of:

Power = 700mm ÷ 25mm = 28

Similarly, if the MH9mm eyepiece is used, the resulting power will be 700mm ÷ 9mm = 78x. Meade eyepieces present extremely sharp, well-resolved images through the Model 230 throughout a wide range of magnifications.

A few words of wisdom about power. While the theoretical power or magnification of a telescope is virtually limitless, there are, however, practical limits imposed by the Earth's atmosphere as to what can be seen well at a given power. The most often useful higher magnification with any 60mm diameter telescope is in the range of 80 to 120 power. The general rule to follow with any telescope, regarding power: only use as much magnification as a steady, well-defined image supports. This often varies with the stability of the air being viewed through and is one reason why having various eyepieces is highly desirable. Higher powers are no guaranty of better images; in fact, the opposite is often true. Also, keep in mind, that land viewing and wide-field, deep-space observation are, generally, low power applications of your telescope.

[ toc ] MAINTENANCE

As with any quality optical instrument, lens surfaces should be cleaned as infrequently as possible. A little dust on the surface of the objective lens causes negligible degradation of image quality and should not be considered reason to "clean" the lens. When lens cleaning does become necessary, use a camel's hair brush or compressed air to gently remove dust. Wipe only with a soft, clean cloth, applying as little pressure as possible to avoid scratching glass surfaces. Note: Remove the dew shield/lens shade (21) to access the objective lens (14).

[ toc ] SPECIFICATIONS

Objective (main) lens focal length: 700mm
Objective lens diameter: 60mm (2.4")
Focal ratio: f/11.7
Mounting type: Altazimuth

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