Introducing the Meade Model 285 This Manual Standard Equipment Unpacking and Assembly Balancing the Telescope Alignment of the Viewfinder Understanding Celestial Movements and Coordinates Using the Telescope Using Setting Circles Calculating Power Maintenance Cleaning Mount Adjustments Specifications: Model 285

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 ] A. Introducing the Meade Model 285

The Model 285 is an easy-to-operate, high performance 60mm refracting telescope, intended for astronomical and terrestrial (land) observing. Equipped with a deluxe equatorial mount and aluminum tripod, the telescope's motion is continuously adjustable for tracking celestial or land objects. Your telescope comes to you ready for adventure; it will be your companion in a universe of breathtaking landscapes, planets, galaxies, and stars.

1. Tripod legs
2. Equatorial mount
3. R.A. flexible cable control
4. Dec. flexible cable control
5. Counterweight
6. Counterweight shaft
7. Counterweight lock
8. Safety washer/knob
9. Latitude lock
10. Polar axis
11. Latitude adjustment knob
12. Telescope optical tube assembly
13. Saddle plate for mounting optical tube
14. Optical tube mounting wing-nuts
15. Optical tube mounting bolts
16. Diagonal mirror
17. Focuser
18. Focuser thumbscrew
19. Eyepiece
20. Diagonal thumbscrew
21. Declination axis
22. R.A. lock
23. Dec. lock
24. 5 x 24 viewfinder
25. Viewfinder bracket
26. Viewfinder bracket thumbscrews
27. R.A. setting circle
28. Dec. setting circle
29. Latitude dial
30. Azimuth lock
31. Focus knobs
32. Polar shaft acorn cap nut
33. Azimuth base
34. Azimuth shaft bolt
35. R.A. worm block assembly
36. Dec. worm block assembly
37. Dew shield
38. Objective lens cell
39. Accessory shelf with attachment knob
40. Leg braces
41. Front lens dust cover
42. Adjustable sliding leg extension
43. Sliding inner leg extension thumbscrew lock
44. Tripod-to-mount attachment bolts

[ toc ] 1. This Manual

These instructions detail the set-up, operation, specifications, and optional accessories of your Meade Model 285. In order that you may achieve maximum enjoyment 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 this manual, the technical terms associated with telescopes will be made clear.

[ toc ] 2. 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 = 900mm; f/15.

–Equatorial mount with pre-attached, continuously adjustable, aluminum tripod and leg braces.

–Accessories:

MA 25mm (36x) and MH 9mm (100x) eyepieces (1.25" O.D. )
Hybrid diagonal mirror (fits into the telescope's .965" focuser, and accepts 1.25"-barrel diameter eyepieces)

Counterweight with counterweight shaft

Flexible cable controls for both telescope axes

Accessory shelf

[ toc ] B. Unpacking and Assembly (Numbers in brackets below refer to Fig. 1)

Your Meade Model 285 comes to you packaged almost entirely pre-assembled. You will find upon opening the giftbox that there are two compartments within that contain the optical tube assembly and the tripod with equatorial mount. The accessories described above will be located within compartments custom-cut into the styrofoam block inserts. (References herein–e.g.,(6)–are to Fig.1 unless otherwise specified.)

(1) Remove and identify the telescope's Standard Equipment listed in Section A.2., above.

(2) Spread the tripod legs (1) to full extension so that the leg braces are taut (should one of the tripod leg braces slip out of the center triangle fastener, merely reposition the brace and slide it back into position). Adjust the tripod with the attached equatorial mount (2) to the desired height by loosening the tripod lock knobs and extend the sliding inner section of each tripod leg; then tighten each knob. Note that these knobs need only be tightened to a "firm feel." Overtightening the tripod lock knobs can result in damage to the knob or the tripod leg itself.

(3) Remove the mounting knob from the round accessory shelf. Place the accessory shelf on top of the center triangle leg brace fastener of the tripod so that the threaded stud protruding from the bottom of the shelf passes through the hole in the center. Then replace and tighten the accessory shelf mounting knob.

(4) Attach the flexible cable controls (3) and (4). These cable controls are secured in place with a firm tightening of the thumbscrew located at the end of each cable.

(5) Holding the counterweight (5) firmly in one hand, slip the counterweight onto the counterweight shaft (6). Attach the counterweight (5) and counterweight shaft (6), by supporting the unlocked (7) counterweight firmly in one hand, while threading the counterweight shaft into the base of the Declination axis of the telescope's equatorial mount with the other (see Fig. 1). Once firmly attached, slide the counterweight to about 3" from the bottom of the counterweight shaft (approximate balance point) and secure it in place with the thumbscrew lock (7) of the counterweight. Note: If the counterweight ever slips, the secured threaded safety washer/knob (8) will not let the weight slide entirely off the counterweight shaft. Be certain that this safety washer/knob is always in place.

(6) Attach the viewfinder bracket (25) 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. Orient the placement of the bracket as seen in Fig. 1. Place the viewfinder (24) into the viewfinder bracket rings by backing off the thumbscrews (26). Then center the viewfinder in both bracket rings using the thumbscrews on each bracket ring. Orient the viewfinder so its front objective lens is pointing in the same direction as the telescope's objective lens (38).

(7) Release the latitude lock (9) of the equatorial mount, and tilt the polar axis (10) of the telescope to roughly a 45° angle by turning the latitude adjustment knob (11). With the polar axis thus tilted, firmly re-tighten the latitude lock.

(8) Remove the wing-nuts (14) from the optical tube mounting bolts (15) that are on the underside of the optical tube (12) of the telescope. Then lay the telescope optical tube assembly onto the saddle plate (13), passing the mounting bolts (14) through the holes in the saddle of the mount. Re-attach the wing-nuts to the mounting bolts, and tighten to a firm feel. Be sure the objective lens (38) of the tube is on the same side of the saddle plate (13) as Declination slow-motion control (4).

(9) Insert the diagonal mirror (16) into the focuser (17), and tighten the focuser thumbscrew (18), to secure the diagonal mirror.

(10) Insert the MA25mm eyepiece (19) into the diagonal mirror, and tighten the diagonal thumbscrew (20) to secure the eyepiece.

The telescope is now fully assembled. Before it can be properly used, however, the telescope must be balanced and the viewfinder aligned.

[ toc ] 1. Balancing the Telescope

In order for the telescope to move smoothly on its mechanical axes, it must first be balanced about the 2 telescope axes: the polar axis (10) and the Declination axis (21). All motions of the polar aligned telescope (more on this later) take place by moving about these two axes, separately or simultaneously. To obtain a fine balance of the telescope, follow the method below:

(Note: if the counterweight is positioned as recommended on the previous page–the telescope is already approximately balanced.)

–Loosen the R.A. lock (22) and rotate the telescope so that the counterweight shaft (6) is parallel to the ground (horizontal).

–Slide the counterweight (5) along the counterweight shaft (6) until the telescope remains in one position without tending to drift down in either direction. Then tighten the counterweight lock knob (7), locking the counterweight in position.

The telescope is now properly balanced.

[ toc ] 2. Alignment of 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. The 5 x 24 viewfinder (24) and viewfinder bracket (25) must be attached to the main telescope tube as in Fig. 1.

In order for the viewfinder to be functional, however, it must be aligned to the main telescope, so that both the viewfinder and main telescope point at the same position in the sky. With this simple alignment performed, finding objects is greatly facilitated, since you will first locate an object in the wide-field viewfinder, then you will look in the eyepiece of the main telescope for a detailed view. To align the viewfinder follow these steps:

(1) Remove the telescope front dust cover (41).

(2) Place the low-power (MA25mm) eyepiece into the focuser of the main telescope.

(3) Loosen the R.A. lock (22) and the Dec. lock (23) just enough so that the telescope turns freely on both axes. Next, point the main telescope at some well-defined land object (e.g. the top of a telephone pole) at least 200 yards distant. Then re-tighten the R.A and Dec. axes locks. Turn the flexible cable controls, (3) and (4), to center the object in the telescopic field.

(4) With the front of the viewfinder (see Fig. 1) already centered in the front bracket ring, look through the viewfinder and loosen or tighten, as appropriate, one or more of the rear viewfinder bracket ring thumbscrews (26) until the viewfinder's crosshairs are likewise centered on the object previously centered in the main telescope.

(5) Check this alignment on a celestial object, such as a bright star or the Moon, and make any refinements necessary, using the method outlined above.

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

[ toc ] C. Understanding Celestial Movements and Coordinates

To line up the Model 285 with the pole, follow this procedure:

1) Release the Azimuth lock (30) of the Azimuth base (33), so that the entire telescope-with-mounting may be rotated in a horizontal direction. Rotate the telescope until the polar axis (10) points due North. Use a compass or locate Polaris, the North Star (see Fig. 3), as an accurate reference for due North.

2) Level the mount, if necessary, by adjusting the heights of the three tripod legs.

3) Determine the latitude of your observing location by checking a road map or atlas. Release the latitude lock (9) and tilt the telescope mount by turning the latitude adjustment knob (11) so that the pointer indicates the correct latitude of your viewing location on the latitude dial (29). Re-tighten the latitude lock (9).

4) If steps (1) - (3) above were performed with reasonable accuracy, your telescope is now sufficiently well-aligned to the North Celestial Pole for visual observations.

Once the mount has been polar-aligned as described above, the latitude angle need not be adjusted again, unless you move to a different geographical location (i.e. a different latitude). The only polar alignment procedure that needs to be done each time you use the telescope is to point the polar axis due North, as described in step (1) above.

[ toc ] D. Using the Telescope

With the telescope assembled, balanced and polar aligned as described above, you are ready to begin observations. Decide on an easy-to-find object such as the Moon, if it is visible, or a bright star to become accustomed to the functions and operations of the telescope. For the best results during observations, follow the suggestions below:

–To center an object in the main telescope, slightly loosen the telescope's R.A. lock (22) and Dec. lock (23). The telescope can now turn freely on its axes. Use the aligned viewfinder to first sight-in on the object you wish to observe; with the object centered on the viewfinder's crosshairs, re-tighten the R.A. and Dec. locks.

–Always start an observation with the lower power MA 25mm eyepiece; get the object well-centered in the field of view and sharply focused. Then try the next step up in magnification. If the image starts to become fuzzy as you work into higher magnifications, then back down to a lower power; the atmospheric steadiness is not sufficient to support high powers at the time you are observing. Keep in mind that a bright, clearly resolved but smaller image will show far more detail than a dimmer, poorly resolved larger image. The MA 25mm eyepiece included with the Model 285 presents a wide field of view, ideal for general astronomical observing of star fields, clusters of stars, nebulae, and galaxies; it is also probably the best eyepiece to use in the initial finding and centering of any object.

–Once centered, the object can be focused by turning one of the knobs of the focusing mechanism (31). You will notice that the astronomical object in the field of view will begin to slowly move across the eyepiece field. This motion is caused by the rotation of the Earth on its axis, as described in Section C, although the planets and stars, are, for practical purposes, fixed in their positions in the sky. The platform on which the telescope is sitting ( the Earth) rotates once every 24 hours under these objects. To keep astronomical objects centered in the field of the polar aligned telescope, simply turn the R.A. flexible cable control (3). These objects will appear to move through the field more rapidly at higher powers. Note: the Declination flexible cable control is used only for centering purposes, and not for tracking.

–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.

–You should allow a few minutes to allow your eyes to become "dark adapted" before attempting any serious astronomical observations. Use a red filtered flashlight to protect your night vision when reading star maps or inspecting the components of the telescope.

–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.

–Avoid viewing objects low on the horizon. Objects will appear better resolved with far greater contrast when viewed higher in the sky. Also, if images appear to "shimmer" in the eyepiece, reduce power until the image steadies. This condition is caused by air turbulence in the upper atmosphere.

The number of fascinating objects visible through your Meade refractor is limited only by your own motivation. Astronomical software such as Meade's Epoch 2000, or a good star atlas such as the Meade Star Charts will assist you in locating many interesting celestial objects. These objects include:

• Cloud belts across the surface of the planet Jupiter.

• The 4 major satellites of Jupiter, visible in rotation about the planet, with the satellite positions changing each night.

• Saturn and its famous ring system, as well as several satellites of Saturn, much fainter than the major satellites of Jupiter.

• 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 285.

• Terrestrial objects: Your Meade Model 285 may 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 optional Meade #931 Hybrid 45° Erect-Image Roof Prism (.965" / 1.25") is required. Terrestrial observations should almost always be made using a low-power eyepiece (50X or less), for bright sharp images. Beyond the 50X limit images may appear very poor due to the fact that the images are being viewed through the thickest and most turbulent part of the atmosphere, unlike astronomical observations made by pointing the telescope up and through a thinner atmosphere.

[ toc ] E. Using Setting Circles

Setting circles of the polar aligned equatorial mount can facilitate the location of faint celestial objects not easily found by direct visual observation. To use the setting circles, follow this procedure:

–Use a star chart or star atlas, and look up the celestial coordinates, Right Ascension and Declination (R.A. and Dec.), of an easy-to-find bright star that is within the general vicinity of the faint object you wish to locate.

–Center the determined bright star in the telescope's field of view.

–Manually turn the R.A. setting circle (27) to read the R.A. of the object now in the telescope's eyepiece.

–The setting circles are now calibrated (the Dec. setting circle (28) is factory calibrated). To locate a nearby faint object using the setting circles determine the faint object's celestial coordinates from a star chart, and move the telescope in R.A. and Declination until the setting circles read the R.A. and Dec. of the object you are attempting to locate. If the above procedure has been carefully performed, the faint object will now be in the vicinity of the telescope's field of view with a low power eyepiece

–The R.A. Setting Circle must be manually re-calibrated on the current Right Ascension of a star manually every time the telescope is set up, and reset to the centered object's R.A. coordinate before moving to a new R.A. coordinate setting. The R.A. Setting Circle has two sets of numbers, the inner set is for southern hemisphere, while the outer set of numbers (the set closest to the R.A. gear), is for use by observers located North of the Earth's equator (e.g. in North America).

[ toc ] F. Calculating Power

The power, or magnification of the telescope depends on two optical characteristics: the focal length of the main telescope and the focal length of the eyepiece used during a particular observation. For example, the focal length of the Model 285 telescope is fixed at 900mm. To calculate the power in use with a particular eyepiece, divide the focal length of the eyepiece into the focal length of the main telescope. For example, using the MA 25mm eyepiece supplied with the Model 285, the power is calculated as follows:

  Meade Instruments manufactures several types of eyepiece designs that are available for your telescope. The type of eyepiece has no bearing on magnifying power but does affect such optical characteristics as field of view, flatness of field, eye-relief, and color correction.

The maximum practical magnification is determined by the nature of the object being observed and, most importantly, by the prevailing atmospheric conditions. Under very steady atmospheric "seeing," the Model 285 may be used at powers up to about 225x on astronomical objects. Generally, however, lower powers of perhaps 75x to 180x will be the maximum permissible, consistent with high image resolution. When unsteady air conditions prevail (as witnessed by rapid "twinkling" of the stars), extreme high-power results in "empty magnification," where the object detail observed is actually diminished by the excessive power.

Optional accessory eyepieces are available both to increase and decrease the operating power of the telescope. If the Model 285 is used on a regular basis, a selection of four to five eyepieces is a worthwhile investment to get the most performance from your telescope. For example, an eyepiece assortment of focal lengths 32mm** or 40mm, 25mm*, 12mm, 9mm*, and 5mm yields a magnifying range of 28x or 22.5x, 36x, 72x, 100x, and 180x respectively.

* Included as standard equipment with the Model 285.
** A 32mm or 40mm eyepiece is an excellent low-power, wide field eyepiece, highly recommended for observing large star fields and nebulae, or for land viewing.

[ toc ] G. Maintenance

[ toc ] 1. Cleaning

As with any quality instrument, lens or mirror surfaces should be cleaned as infrequently as possible. Coated lens surfaces, in particular, should be cleaned only when absolutely necessary. In all cases avoid touching any optical surface. A little dust on the surface of a lens or mirror causes negligible loss of performance and should not be considered reason to clean the surface.

When lens cleaning does become necessary, use a camel's hair brush or compressed air gently to remove dust. If the telescope's dust cover is replaced after each observing session, cleaning of the optics will rarely be required. Note: remove the dew shield (37) to access the objective lens (38) for cleaning.

[ toc ] 2. Mount Adjustments

Every Meade Model 285 equatorial mount and tripod is factory inspected for proper fit and function prior to shipment. It is unlikely that you will need to adjust, or tighten these parts after receipt of the telescope. However, if the instrument received unusually rough handling in shipment, it is possible that some of these assemblies can be loose. To make adjustments you will need a 1/2" or 11/16" socket or adjustable end wrench, a 5/64" hex wrench, and a Phillips-head screwdriver.

The equatorial mount has four main areas that can be adjusted: A loose polar shaft can be tightened by releasing a 5/64" hex set-screw that is on the side of the 11/16" polar shaft acorn cap nut (32), and then turning the 11/16" acorn cap nut clockwise to a firm feel, and then tightening the 5/64" hex set-screw. A loose Azimuth base (33), can be tightened by turning the 11/16" Azimuth shaft bolt (34), that is located underneath the mount and in between the three tripod legs, clockwise to a firm feel. The R.A. (35), and Dec. (36) worm block assemblies can have backlash removed by releasing the 2 Phillips-head screws on each assembly, applying pressure to the worm block against the worm gear, and then tightening the Phillips-head screws. Note that overtightening of any of the nuts, bolts, or screws can inhibit the smooth rotating action of the axes and gears, and may result in stripping the threads.

The tripod legs have 1/2" nuts that may have backed off; these should also be tightened to a firm feel.

[ toc ] H. Specifications: Model 285

Objective (main) lens focal length: 900mm
Objective lens diameter: 60mm (2.4")
Focal ratio: f/15
Mounting : Equatorial, German-type

Related Topics:

• Authorized Dealers
• Index of Instruction Manuals
• General Catalog Index
• Meade Product Repair and Warranty Information