Meade Essential Guide to Spider Vanes and Collimation in Newtonian Telescopes
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Fig. 4: Newtonian Reflecting Telescope. (1) Spider Vanes; (2) Secondary Mirror; (3) Parabolic Primary Mirror; (4) Primary Mirror Hex Screws;

(5) Focuser Drawtube; (6) Focused Image.

Face-on view

Edge-on view

1

3

2

Fig. 5: Secondary Mirror Assembly. (1) Spider Vanes; (2) Tilt Screws; (3)Secondary Mirror Holder.

Correct Collimation

A properly collimated (aligned) mirror system in your Starfinder Dobsonian telescope assures the sharpest images possible. Your Starfinder is properly aligned when the primary mirror

(3, Fig. 4) and secondary mirror (2, Fig. 4) are tilted so that the focused image (6, Fig. 4) falls directly through the center of the focuser drawtube (5, Fig. 4).

To inspect the view of the mirror collimation, remove the eyepiece and look down the focuser drawtube. The round edge of the focuser drawtube (1, Fig. 6) will frame the reflections of the primary mirror with the secondary mirror (2, Fig. 6) the spider vanes (3, Fig. 6) and your eye (4, Fig. 6). Properly aligned, all of these reflections will appear concentric (i.e. centered) as illustrated in Fig. 6. Any deviation from the concentric reflections will require adjustments to the secondary mirror assembly (Fig. 5), and/or the primary mirror cell.

Spider Vane Adjustments

Looking down the open end of the telescope tube, check to see if the secondary mirror system is centered in the optical tube. If the assembly is off-center, loosen one of the spider vane adjustment/lock knobs while unscrewing the opposite knob. Only make adjustments to 2 knobs at a time until the secondary mirror is centered in the drawtube. When the spider vane is correctly positioned, the view through the drawtube will look like

Fig. 6: Correct Collimation. (1) Round Edge of Focuser Drawtube;

Fig. 8: Secondary Mirror Misalignment. (1) Secondary Mirror;

2) Secondary Mirror; (3) Spider Vanes; (4) Eye.

(2) Round Edge of Focuser Drawtube; (3) Reflection of Primary Mirror.

Fig. 7: Spider Vane Misalignment. (1) Secondary Mirror; (2) Round

Fig. 9: Primary Mirror Misalignment. (1) Secondary Mirror; (2) Round

Edge of Focuser Drawtube.

Edge of Focuser Drawtube; (3) Eye.

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Contents Meade Instruments Corporation Meade Starfinder Dobsonian Telescope Contents Parts Listing and Assembly IntroductionAssembling the Mount Balancing the Telescope ViewfinderCollimation of the Optical System Spider Vane Adjustments Correct CollimationStar Testing the Collimation Secondary Mirror AdjustmentsPrimary Mirror Adjustments Tips on Using a Dobsonian TelescopeObserving Guidelines Optional AccessoriesSeeing Conditions Care of Optics and Main TubeMeade Customer Service Telescope Meade Limited Warranty Ver

12.5 specifications

The Meade 12.5-inch telescope is a testament to cutting-edge optical technology, designed for both amateur astronomers and serious astrophotographers. Its robust build and impressive specifications make it a popular choice among stargazers looking to explore the finer details of celestial objects.

One of the main features of the Meade 12.5 is its large aperture of 12.5 inches, or 318 millimeters. This sizable opening allows for a significant amount of light to enter the telescope, resulting in bright and clear images of distant galaxies, nebulae, and clusters. The vast light-gathering capability is particularly advantageous when observing faint objects, providing enhanced detail not achievable with smaller apertures.

The Meade 12.5 utilizes advanced optics, often incorporating premium-grade glass elements. This ensures minimal optical aberrations, resulting in sharp, high-contrast images. Many models also feature a parabolic primary mirror, which optimizes focus across the entire field of view, making it ideal for high-resolution observations.

In terms of technology, many Meade 12.5 telescopes come equipped with computerized mount systems. These mounts utilize GoTo technology, enabling users to easily locate and track celestial objects. With a database containing thousands of celestial bodies, users can simply input the desired object, and the telescope will automatically reposition itself for optimal viewing. This automation makes it easier for beginner and intermediate users to navigate the night sky.

Another notable characteristic of the Meade 12.5 is its sturdy construction. The telescope's design typically includes an aluminum or steel optical tube, providing stability and durability during observations. This is crucial for maintaining alignment and ensuring that the optical components remain secure, reducing vibrations that could hinder image quality.

Additionally, many models feature cooling fans that help to regulate the temperature of the primary mirror. This is particularly important for astrophotography, as temperature fluctuations can lead to distortions in the images captured. The cooling system ensures that the telescope reaches thermal equilibrium more quickly, allowing for clearer, more stable observations.

Overall, the Meade 12.5-inch telescope stands out due to its excellent optics, advanced technology, and robust design. Whether for deep-sky viewing or astrophotography, it offers a highly capable platform that caters to the diverse needs of astronomers. Its combination of features makes it a worthy investment for anyone serious about exploring the wonders of the universe.
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