telescope finderscope auxiliary monocular
Telescope Nerd » Finderscope For Telescope: Alignment and Types

Finderscope For Telescope: Alignment and Types

The finderscope is a part of a telescope that helps locate and center celestial objects in the primary telescope. Knowing the design and function of a finderscope allows astronomers to accurately and efficiently locate celestial objects. 

The finderscope is a secondary telescope mounted atop the Optical Tube Assembly (OTA), designed specifically to help astronomers locate objects more easily. The finderscope locates objects by offering a wider field of view and lower magnification than the primary telescope. Most finderscopes also have crosshairs or a reticle, which centers the target object for the primary telescope. The field of view, magnification, and reticle make it easier to pinpoint specific celestial objects before viewing them through the main telescope.

Finderscopes are typically made from materials like plastic or metal, with lenses made of glass or acrylic. The choice of material will affect the finderscope’s weight, durability, and clarity of the image. The finderscope needs precise alignment and proper attachment to the primary telescope to pinpoint objects accurately.

How to Align a Finderscope With a Telescope?

To align a finderscope with a telescope, astronomers must point the telescope toward a distant object during the day, position it until it’s centered in the eyepiece, make necessary adjustments using the finderscope’s screws, recheck the primary eyepiece and refine the alignment at night using a bright star. 

Begin the alignment process during the daytime to ensure accurate setup using clear landmarks. Point the telescope towards a fixed distant object, like a tree’s tip or a building’s edge. The objective is to make discrepancies evident against a clear, unmoving backdrop.

With the telescope’s eyepiece at its lowest magnification, adjust its positioning until the chosen object sits squarely in the center of the eyepiece’s view. This central alignment ensures that the primary scope is accurately targeted.

Upon viewing through the finderscope, if the targeted object isn’t centered, one must make adjustments. Every finderscope has adjustment screws, which are typically small, round or hexagonal in shape, and are found on the side or base of the finderscope. While maintaining the view through the finderscope, gently tweak these screws. The goal is to bring the distant object to sit at the crosshairs’ intersection or under the red dot, depending on the finderscope type.

Toggle back to the telescope’s primary eyepiece and recheck its image. If the previously centered object has drifted off-center, repeat the process until both scopes precisely coincide. Once nighttime falls, pick a bright star to refine the alignment. The star’s singular brightness amidst the vast dark provides a pinpoint location for refining the finderscope’s aim.

Though the core alignment methodology remains consistent across finderscopes, the fine-tuning and adjustment details will differ in different types. Always consult the finderscope’s specific manual to ensure correct alignment procedures.

How to Attach a Finderscope to the Optical Tube?

To attach the finderscope to the optical tube, position the bracket on the tube’s designated spot, secure it with the provided screws, slide the finderscope into the bracket and make adjustments to ensure precise alignment. The optical tube is the main body of the telescope where the primary optics reside, such as mirrors or lenses. It’s pivotal for gathering and focusing light to produce the images we see.

Most optical tubes come with predetermined spots for finderscope attachment, often denoted by small screws or brackets. If the brand or model of the finderscope and the optical tube don’t match, one needs a specific bracket or holder to ensure a secure fit.

Position the bracket onto the predetermined spot on the optical tube. Using the screws provided, securely fasten the bracket to the tube, ensuring it’s snug but not overtightened, which damages the tube. 

Once the bracket is in place, slide the finderscope into it. There will be thumb screws or another mechanism to securely hold the finderscope in its bracket. Initially, the finderscope generally will not perfectly align with the main telescope optics. 

To achieve precise alignment, one must make adjustments, ensuring that what is seen in the finderscope matches the view in the telescope’s eyepiece. Adjusting typically involves turning small screws or knobs on the finderscope mount until both views are synchronized.

Different brands or types of telescopes have unique mechanisms or steps. Always refer to the user manual of the specific telescope and finderscope for any specialized instructions.

Is Finderscope an Important Part of the Telescope?

Yes, the finderscope is a crucial component of a telescope. Its primary function is to help users locate and center celestial objects before observing them through the main telescope, which often has a much narrower field of view. Without the aid of a finderscope, pinpointing distant stars, planets, or other celestial phenomena would be much more time-consuming.

One of the key advantages of a finderscope is its wide field of view. This part of a telescope allows for a broader perspective of the night sky, making it easier to identify and align targets. Once an object is centered in the finderscope, it ensures that the same object will be within the viewing range of the main telescope, even if the main optics have a highly magnified and limited view.

While the main optics of a telescope produce detailed and magnified images, the finderscope serves as an essential navigational tool, guiding users to their desired celestial destinations with ease and accuracy.