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Telescope Filters

What are Telescope Filters?

Telescope filters are used by professional and budding astronomers alike to improve the clarity of objects in the sky when viewed through a telescope eyepiece or camera. Filters can reduce the appearance of specific colors and wavelengths of light. By doing this, the filter enhances visual or photographic contrast and brings out the details of stars, planets and other astronomical objects. There is a telescope filter for just about every application. A light pollution filter is one of the most popular — no filter can block all forms of light pollution, but they can reduce its effects to provide a better viewing experience.

How to Choose & Use Telescope Filters

If you are new to the world of telescope filters, the huge variety of filter types and sizes can be overwhelming. However, if you filter your results by the "filter size" and either the "filter type" or "primary purpose" in our left-hand navigation, it will go a long way towards narrowing down the field.

Filter Size: Let's say you are looking for a moon filter. Before you start shopping, you'll need to know what size moon filter you need. The most popular moon filter comes in a threaded 1.25" cell, like this Celestron moon filter, and if you plan to use a standard 1.25" eyepiece to look at the Moon, then this is the filter size you need. The same is true if you are using any other type of filter that is designed with a 1.25" or 2" threaded cell, just remember you need to match the filter size to the eyepiece barrel size and you'll be good.

Since we look through an eyepiece when doing visual astronomy, it makes sense that any filters meant to be used in conjunction with an eyepiece would have compatible threads so the two can be safely connected. However, when doing astrophotography, threaded filters are not always necessary. There are exceptions, such as when using a standard entry-level filter wheel or filter carousel that accepts 1.25" filters, but most other filter wheels use filters that are not threaded. Different filter wheels use different sized filters, which is why you see so many sizes in the same filter type. If you have a filter wheel or camera with an integrated filter wheel, then you know what size filter you need, so again, filtering in our left-hand navigation by Filter Size will narrow down your choices.

Telescope Filter Types

There are many different telescope filter types available to suit a wide range of stargazing and astrophotography needs. Some of the most common types of telescope filters are:

To learn more about the different telescope filter types, make sure to check out the High Point Scientific Filter Guide.

A Note About Broadband, Midband & Narrowband Filters

While these aren't necessarily telescope filter types in and of themselves, "broadband", "midband" and "narrowband" are terms used to describe the wavelength of light transmission that each filter will allow, with narrowband allowing the smallest portion of the light spectrum through and broadband allowing the widest.

Buy the Best Telescope Filters Online at High Point Scientific

As always, we would be more than happy to help you pick the best filter for your telescope and applications. If you have any questions, please contact us — our non-commissioned experts are ready to help you get the best stargazing experience possible.

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