How To Put A Filter On A Telescope | 4 Actionable Steps




How To Put A Filter On A Telescope

Affiliate Disclaimer

As an affiliate, we may earn a commission from qualifying purchases. We get commissions for purchases made through links on this website from Amazon and other third parties.

To attach a filter onto your telescope, first select the type of filter, prepare the eyepiece lens and remove it, thread the filter into the eyepiece barrel, and replace the lens. While preparing the eyepiece and the lens, ensure that they do not fall or get scratched

To get the most out of your viewing experience of space objects, you’ve undoubtedly heard that you should use a telescope filter to improve the quality of your images.

According to assessments, they bring out more colors and features in the planets and stars, and they are a must-have if you’re just getting started with astronomy since they will completely transform your experience.

Continue reading the article for more information on putting a filter on your telescope, types of filters, and more.

What Exactly Are Telescope Filters?

Telescope filters prevent undesired light waves from penetrating the telescope and entering your eyes, which can cause the vision to become distorted.

There are many distinct filters, each with its own set of functions. Keeping this in mind, let’s have a look at some of the steps involved in installing a filter on your telescope.

How to Put a Filter of Your Telescope in 4 Easy Steps 

Putting a filter to your telescope is a piece of cake and will take you a minute. 

Let’s have a look

Step 1

Choose the filter you want to use. There are a variety of filters that you can fit onto a telescope. So make sure you have the right one. 

Step 2

Now that you have the filter of your choice, Do not forget to check the size of the filter; they come in sizes. Now prepare the lens of the telescope.

To prepare the lens of a telescope, take off the caps carefully and ensure that you do not scratch the lens, drop or touch the lens with bare fingers. 

Bare hands or fingers have natural body oil that will affect visibility.

Step 3

After preparing the lens, it tome to screw in the filter. Every filter has threads, So identify where the filter attaches to the lens and screw it in slowly. 

Ensure that the grooves align. The male and female threads should be in the same alignment to ensure they fit in at an angle of 180 degrees. 

Ensure that you do not put the filter directly into the telescope because this will damage the filter. 

Step 4

Once the filter has fitted perfectly, now return the lens carefully as you normally do. Be careful not to scratch the lens because it is very sensitive.

Once you have placed back the lens, you are ready to use the filter. 

Is It Necessary To Use A Telescope Filter?

The simple answer to this question is yes. Assuming you’ve just acquired a telescope, you’re probably under the impression that a filter isn’t necessary.

The reason for this is that you will most likely begin your astronomy trip by staring at the brilliant Moon and stars, which are among the easiest objects in the sky to observe without any special equipment at this time.

However, as you move further into the night sky, you will discover that you will be at a distinct disadvantage in your photography if you do not utilize filters. It is possible to observe more objects and their stunning features using telescope filters.

When looking at the wonders of the sky, you must make certain that you have three essential ingredients. Contrast, sharpness and the amount of light available to you for seeing astronomical objects are the three factors to consider.

The latter will be determined by the telescope’s aperture you are using. Nonetheless, the application of filters may significantly increase the contrast and clarity of your views.

These filters all have one key thing in common: they reflect some light while blocking out the rest, making celestial objects seem sharper and more visible.

Consider the following scenario. The usage of a telescope filter is like walking outdoors on a bright day and attempting to observe an item on a fence while wearing sunglasses.

When you don’t use your hand to hide your eyes from the thing, it isn’t easy to notice it.

The fact that it’s an item and probably part of its coloring will be visible, but you will be blind to the rest of its characteristics. When you shield your eyes with your hand, you block away from the brightness of the sun, which immediately brings the item into sharper focus, allowing you to see more of its finer characteristics.

An optical telescope filter accomplishes exactly that: it reduces glare and light pollution, allowing you to see more stars and planets by blocking out part of the light and reflections.

What Are the Different Types of Telescope Filters?

For those interested in seeing the night sky, various telescope filters are available. Here are the primary categories of astronomy that every beginning astronomer should be familiar with.

Solar Filters

This type of filter allows you to stare directly at the sun, as suggested by its name. However, it is critical to use the best filters possible, full-aperture filters.

Because they’re made of a flexible film or glass that covers the telescope’s end, they’re more secure than other solar filters on the market. A large reduction in UV radiation, heat, and light from the sun that reaches the telescope is expected.

You are attempting to stare at the sun, so exercise caution when using these solar filters.  Even if you look directly at the sun for a brief second by accident, it is always harmful to look directly at it.

The H-alpha (hydrogen-alpha) filter is another useful solar filter that you should experiment with. More activity in the sun is visible as a result of this.

Solar filters that emit white light will allow you to view the sunspots on the sun’s surface and will be handy for seeing solar eclipses, as well. 

On the other hand, H-alpha filters are superior because they transmit just one wavelength of light, a deep red color emitted by hydrogen atoms while blocking all others.

An H-alpha filter will allow you to observe what is going on in the chromosphere. You’ll be able to notice hydrogen since it emits a reddish glow in this area.

Using the H-alpha filter, you may also use the H-alpha filter to see brilliant nebulae and solar eclipses more clearly.

It is great to observe the eclipse via this sort of telescope filter. Because it only enables light with a wavelength of 656 nanometers to get through, it prevents the harmful ultraviolet radiation from the sun from reaching your eyes. 

Filters for the Lunar Sky

These telescope filters aid in the observation of the Moon by reducing the quantity of light emitted over the whole visible spectrum.

Main Types of Lunar Filters

A Neutral Density Filter– darkens a large or small portion of the Moon’s surface. Neutral density filters are used to darken a large or small portion of the Moon’s surface.

Some lunar filters are available in green hues, which assist in lessening the amount of glare that you perceive when looking at the Moon in the night sky.

A Variable Moon Filter– allows you to adjust the amount of light that passes through it by adjusting one of its polarisers.

A variable moon filter is a fantastic choice to see the Moon during its many phases. Depending on your preferences, it allows you to increase the amount of light when the Moon is in its crescent phase and reduce the amount of light when the Moon is in the gibbous phase.

The usage of a moon filter is beneficial not only for improving your ability to see the Moon’s intricacies but also for making your viewing experience more comfortable — the Moon is brilliant and, as a result, can be uncomfortable to stare at times!

Color Filters 

When it comes to seeing the planets, these are excellent filters to have on hand.

These are available in a single color, such as mauve or indigo, and they work by filtering out all of the colors in the scene you’re watching, except for the color of the filter itself. 

This implies that your photographs will have more contrast, which will enhance the details you notice in the sky while shooting at night.

When viewing certain planets, the usage of different colors will allow you to see more details, but you must know which filter to use for whatever planet because they do not come standard with the game.

In the case of Mars, applying a red filter will allow you to see more detail in the marks on the planet’s surface.

Other Color Filters 

Here are some more color filters that will be handy depending on the planet you choose to view, so you won’t have to waste time figuring out which one to use when viewing the solar system.

#25 Red Filter

If you want to view Mercury clearly, you should use this filter. This will brighten the planet’s disk, and it will allow you to see Mercury at twilight. Keep in mind that it is best to attempt to see Mercury immediately after sunset if you want to see it at its best.

#47 Violet Filter

If you want to view Venus, you need to use this filter. This will help decrease the excessive brightness that can result in a picture that is either overexposed or over brightened.

#15 Deep Yellow Filter 

If you want to view Saturn, you’ll need this filter to reveal its details. As a bonus, this filter is an excellent tool for sharpening your astrophotography photographs.

If you want to utilize a color filter, you must screw the filter into the eyepiece’s barrel. It’s quite simple, just like all other filters, and it’s possible to stack them.

Filters for Light Pollution

It is possible that artificial light, such as that created by homes and lighting, will substantially obstruct your views of the night sky. A light pollution filter minimizes the amount of light pollution in the atmosphere, making the sky darker—this aids in discovering celestial bodies such as nebulae.

It is a common misperception that light pollution filters make nebulae appear brighter; they have the opposite effect. On the other hand, increasing the contrast is necessary to properly capture the details in them, particularly around their perimeter.

The narrowband filter is a light pollution filter that you may use.

What Is A Narrowband Filter, And How Does It Work?

If you wish to catch the nebulae or other deep-sky objects, this filter is great for you. It works because it only allows particular emissions to get through while blocking all other emissions. 

The sky darkens, yet the quality of the celestial object you’re interested in seeing does not suffer as a result. This technique also increases the amount of contrast required for faint celestial objects.

Even though they are fairly adaptable, narrowband filters will operate even in locations where there is a considerable quantity of air pollution and with a medium magnification.

What Effect Do Telescope Filters Have On Your Vision

The Moon Vision 

As a result of the Moon’s bright appearance, it might not be easy to see features such as craters, rilles, and mountains on Earth. If you install a neutral density filter on your telescope, it is possible to view the lunar surface in comfort. It will also aid in creating contrast, allowing the features to stand out more.

Deep-Sky Vision 

This is a wonderful all-around filter if you’re looking for wispy deep-sky objects. It detects two oxygen lines and one hydrogen line generated by emission and planetary nebulae, distinguishing them from one another. 

Planetary Vision  

The intricacy in the marks on Mars is brought out more clearly with a red filter. Depending on what you wish to see more clearly, you may apply various colored filters.

Green, for example, would darken the planet’s surface, allowing you to see more of the polar caps if you were to fly over it.

Types Of Telescope Filters That Are Worthwhile To Invest In

Light Pollution Filters 

These can significantly enhance your view of the skies if you live in an urban region since they will block out the majority of the primary sources of illumination and the resultant glare.

Luna Density 25% Filters 

A 25 percent reduction in reflected glare from the Moon will be achieved as a result. This not only makes for a more pleasant viewing experience but also boosts contrast and clarity.

Color Filters 

Color filters bring out the details in planetary characteristics – in this image of Jupiter taken with red, green, and blue filters, the planet’s atmosphere takes on a whole new dimension.

Our Top Four Recommended Telescope Filters 

Orion 05662 1.25-Inch 13% Transmission Moon Filter

Recommended Filter
Orion 05662 1.25-Inch 13% Transmission Moon Filter

The Orion 1.25 inch 13% transmission moon filter is one of the best telescope filters for reducing glare and improving contrast. A direct fit to the telescope’s 1.25-inch eyepiece increases image quality. As a result, the telescope sees a crisper, more contrasted image.

The enhanced contrast given by the 1.25 inch 13% transmission moon filter allows the astronomer to observe the Moon in detail. This Orion Moon filter is unique in that it doesn’t change color despite decreasing brightness.

This eyepiece filter helps decrease irradiation, which loses visual quality at the boundary of light and dark. It also preserves dark-adapted eyesight when viewing the Moon.

As a result of its neutral color, this Orion moon filter eliminates glare, fits directly over the 1.25-inch eyepiece of the instrument, and allows just 13% of light through to increase contrast.

8″x8″ Solar Filter Sheet for Telescopes

Recommended Filter

Telescope filters aren’t just for the Moon. A solar filter will help an astronomer see the sun. The silver-black polymer filter helps here. 

You may buy this sheet and create your filter, saving money.

This silver-black polymer filter is commonly used to see solar flares, depictions, and eclipses via telescopes and binoculars.

Thousand Oaks Optical, Arizona, has made safe sun filters for over 30 years. With this filter, the sun appears in its natural orange hue. This filter sheet is an excellent alternative to pricey, readily available solar filters.

Orion 05598 1.25-Inch 25 Percent Transmission Moon Filter

Recommended Filter
Orion 05598 1.25-Inch 25 Percent Transmission Moon Filter

Designed by Orion, this telescope filter transmits 25% of incoming light while causing minimum dimming. Since tiny aperture telescopes do not require dimming, they work wonderfully.

Since only a small quantity of light is allowed to get through, the overall brightness is less disturbing than it would be in a larger aperture telescope like the Hubble Space Telescope.

It is particularly well suited for observing the Moon during its crescent phases since it does not filter out a considerable amount of light. This is significant since the Moon does not have a conspicuous glare during the crescent phases, therefore utilizing this filter works excellently in preventing just the additional glare and providing maximum viewing quality during these phases.

This filter is designed to fit directly onto the barrel of the 1.25-inch eyepiece and rejects approximately 75% of the light that enters the eyepiece. It gives the viewer a more contrast vision and has less glare than the previous one.

Because this Moon filter boosts contrast without altering the image’s original color, it allows the viewer to enjoy the pleasure of viewing the universe in comfort. It helps to bring out more of the lunar surface details, allowing you to see the craters, valleys, and mountains on the Moon with more clarity.

When it comes to seeing the Moon during its crescent phases, the Orion 1.25-inch, 25 percent transmission filter is one of the best filters available. It does this by blocking precisely the correct amount of light from entering the telescope, resulting in a picture neither too brilliant nor too dark.

​​Neewer 1.25 inches Telescope Moon Filter

Recommended Filter
​​Neewer 1.25 inches Telescope Moon Filter

This filter combination is also considered one of the best telescope filters currently available. The package comprises a moon filter, a CPL filter, and five various colored filters, including Blue, Green, Red, Yellow, and Orange.

The moon filter is included in the price. These filters aid in minimizing eye tiredness that is commonly experienced while using a telescope by enhancing contrast, decreasing and sharpening the image, and making the view more detailed.

By decreasing glare, the moon filter contributes to enhancing the details in the vision. It operates by transmitting only light in the visible spectrum and blocking out all other wavelengths. It is a type of optical filter. 

The CPL filter is the second of the three filters in the set. As a result, this filter can cut through the reflections of light that would otherwise obscure the characteristics of celestial bodies.

Aside from these two color filters, the package contains five other color filters. It helps you see Mercury and Venus more clearly throughout the day and makes them stand out more against the blue sky while you’re outside. 

Saturn’s details are also enhanced as a result of this. The Orange filter allows light to pass through clouds and accentuates the image’s contrast between light and dark regions.

In addition, it aids in the observation of dust storms on Mars, the Great Red Spot, and the planet Jupiter, which is seen more clearly. 

The yellow filter on Mars is distinctive in that it highlights the polar ice caps and deserts on the planet’s surface. The use of a green filter allows for a more detailed picture of Mars and the observation of Saturn’s rings and Jupiter’s belts. It also works well as a moon filter.

The blue filter allows you to see the clouds covering the planet Mars’ atmosphere. The Moon and CPL filters are available in a standard size that will fit the majority of telescopes. You may attach the color filters to the eyepiece by screwing them on.


You might consider investing in some telescope filters if you want to view more detail in the night sky and see it more clearly and crisply. These are simple to install and uninstall, and they provide a plethora of possibilities for improving your views.

Color filters, light pollution filters, and other types of telescope filters have been discussed in detail on this page, allowing you to make informed decisions about which filters are most appropriate for the astronomical objects you wish to photograph or observe.

Looking to learn something new, check out what is flocking a telescope.

Please be careful and use at your own risk
None of the authors, contributors, administrators, or anyone else connected with StarryNova, in any way whatsoever, can be responsible for your use of the information contained in or linked from these web pages.

About the author