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Finding The Best Light Pollution Filter Telescope Module

light pollution over city
» Telescopes » Finding The Best Light Pollution Filter Telescope Module

Are you enjoying the final season of Better Call Saul like I am? If you are, you might have noticed Mike expressing his concerns about whether there’s too much light for his granddaughter to watch the stars with her telescope. And the man knows what he’s saying. Isn’t there too much light for you? If there is, you need to buy the best light pollution filter for telescope, and not settle for less.

This filter is similar to those you can use with your pro cameras (or maybe still use), protecting lenses, filtering UV, or polarizing. With telescopes, though, you might first want to adjust for light pollution, especially tense in urban areas. This article presents a list of lenses that I recommend for use with a telescope.


The Best Light Pollution Filter Telescope Reviews: Connecting Skies to People

Light pollution is inevitable if you live in an urban area. City lights are no obstacle to seeing stars… if the star is Charlie Chaplin. In reality, light from numerous sources disperses in the atmosphere, reflecting from microscopic particles, and spoils star watching just like background noise spoils enjoying the music. A good filter, though, effectively cuts the range of the specter where the noise is found and lets you see the sky bright and clear.

Do light pollution filters work?
How do you tell a good light pollution filter from a bad one? A good city light filter fits your device and does its job, that’s it. Filters are a too specialized segment to bear too many differences. Still, not all of them are created equal. Now, let’s go through some filters considered the best.

My 5 Best Light Pollution Filter Telescope Module

  1. SVBONY 1.25” UHC Filter: the Top Pick
  2. Gosky 1.25” LPF: Runner-Up
  3. Optolong 2” L-Enhance Dual Narrowband LPF: Premium Choice
  4. SVBONY 1.25” Moon Filter: Watch the Moon

1. SVBONY 1.25” UHC Filter: the Top Pick

Key characteristics

  • Brand:‎ SVBONY
  • Photo Filter Thread Size: 31.75 Millimeters
  • Material: Optical Glass, Aluminum
  • Photo Filter Effect Type: Enhancing
  • Size: 1.25 inch
  • Targets: for viewing nebula from light polluted skies; for boosting the contrast

“Astronomer’s favorite brand”; that’s what Svbony claims to be, and it’s mostly true. This brand was founded in China in 2009. What do you know about modern Chinese literature? Me, I only know Liu Cixin, and his The Three-Body Problem (a brilliant sci-fi novel exploring outer space) was published in 2008. Did it influence the founders of Svbony? Did they envision interest in astronomy growing? Or had it already been growing, inspiring both Svbony and Liu Cixin? Anyway, the brand indeed manufactures various astronomy-related products, from telescopes and astronomy cameras to accessories like this filter.

The filter by SVBONY is a 1.25” one suitable for 1.25” eyepieces, the most commonly seen among amateur telescopes. It comes along with other filters by Svbony, the array including specialized moon filters for reducing glare, linear polarizers, and other filters. Some of these filters are even more expensive than an entry-level telescope by the same brand. However, it’s not the case with this one: the price is slightly above $20.

If you are new to this, you’ll be fascinated just by the fact that it has a filter at all. A round-shaped metal frame has a changing color, looking violet or green, depending on the angle. The effect becomes even more stunning once you put it on the eyepiece.

As for parameters, it’s designed to reduce the 400-630 nm emission, except for the range between 465-515 nm, thus filtering the ranges where most of the pollution light lies. The effect of it is seen with the naked eye. The night sky looks darker, and the stars on it appear brighter. It’s exceptionally well seen with nebulae. However, that’s not the case with planets and satellites like the Moon; light pollution will not affect their visibility.

Not only can you view the Universe with this telescope light pollution filter but also take photographs as well. This diameter is mostly used in telescopes designed to view objects in the sky, like stars, planets, nebulae, etc.
Last but not least: this one is made of durable metal and glass and is well protected. The case is filled with foam and does a great job protecting the filter, so you better not dispose of it immediately, especially if you travel a lot with your telescope.

  • Dual broad range filtering;
  • Stunning design;
  • Well protected and durable;
  • Great for astrophotography;
  • Affordable price.
  • Planets won’t look better with it;
  • Can’t be used with other filters.

2. Gosky 1.25” LPF: Runner-Up

Key characteristics

  • Brand:‎ Gosky
  • Photo Filter Thread Size: 30 Millimeters
  • Material: Plastic
  • Photo Filter Effect Type: Enhancing
  • Size: 1.25 inch
  • Targets: enhances contrast on reddish planetary detail.

Gosky is also a well-known optics brand, offering a diverse array of devices, including binoculars, microscopes, and telescopes, and accessories for them. According to its website, it’s a “company registered in the US,” which reads as “Chinese but has a certain quality control for overseas sales.” No wonder a company that manufactures telescopes also has a lot of accessories in store (quite literally). It was established in 2004 in China (the same year in Albuquerque, Mike’s granddaughter watched the sky, and her grandpa watched around for Lalo Salamanca) and has built itself quite a firm reputation.

Unlike the one by Svbony, the filter by Gosky does not cover two distinct ranges but instead filters the range from 20 to 1000+ nm with varying intensity, focusing on filtering the emission at about 300 nm, 570-620 nm, and at about 800 nm. It is an entirely different decision that results in a distinct impression.

In terms of design and usability, though, it shares a lot with our top pick. It is also made of metal (though it looks a little ruder) and comes in an easy-to-carry case. For amateurs, it’s great that it has the “Light Pollution Filter” inscription on the ring, which is more comprehensible for perfect strangers to astronomy than the brief “UHC” on the one by Svbony.

One of the best things about this filter is that it has both male and female threads on its sides. Thus it can be stacked with other filters, which can be a great thing if you know which filters to use. You may even buy those from other brands; as they are designed to fit standard 1.25” eyepieces, they should be compatible with Gosky ones as well unless defective.

The quality… Hmm, if the item you got is decent, you will see the difference. Alas, there is a chance you get a defective one. Luckily, you can file for a replacement. But you will have to prove the one you received does not perform well. But given that its price is well under $30, you can give it a try. Especially if you specifically need a stackable one to experiment with multiple filters at once.

  • Filters the pollution well;
  • Can be used for viewing planetary details;
  • Can be used with other filters;
  • Quite affordable;
  • The inscription makes it recognizable.
  • May underperform in Bortle 6 and above
  • Defective ones appear sometimes.

3. Optolong 2” L-Enhance Dual Narrowband LPF: Premium Choice

Key characteristics

  • Brand:‎ Optolong
  • Material: Plastic
  • Photo Filter Effect Type: Enhancing
  • Size: 2 inch
  • Targets: for excellent light pollution; for color images with color fidelity; for images in urban areas and under the moonlight
  • For which cameras: for DSLR (digital SLR), color CMOS and CCD Astrophotography Cameras

If you believe that sky does not tolerate half-measures and thus you are willing to purchase the absolute premium accessory for watching it clear, the one by Optolong is to look at. Optolong is a Kunming company founded in 1999 and specializing in everything scientific and in premium amateur astronomy.

This filter does not differ from the others by its price. It’s a 2” one, meant for this diameter eyepieces. What difference does it make? The 2” eyepieces are weaker at magnification but provide a better and broader field of view. Thus, 1.25” eyepieces are used for longer distances, like astronomical objects, due to their stronger magnification abilities. The 2” eyepieces are better for watching objects that are closer and take more place, so that they fit in their field of view. In addition, it can be used directly on DSLR and specialized astrophotography cameras with an adapter. Given that it’s designed with light pollution filters for astrophotography in mind, now you get the picture (pun intended).

Not only is this one more expensive because it’s bigger. As you look at its characteristics, it’s clear that it cuts the unwanted wavelengths more precisely, effectively cutting down pollution ranges to highlight those centered around 500 and 680 nm (that is, ionized oxygen and hydrogen-alpha/beta specters typical for nebulae). And it does it with greater precision than any of the filters above.

There are videos on YouTube where astrophotography enthusiasts demonstrate their results without or with L-Enhance. It’s funny how the automatic caption transforms the name. The pictures, though, look serious and demonstrate all the indisputable quality of the item. Well, this is a real one to boast about!

This filter only comes in a 2” version, which makes it more suitable for 2” eyepieces and DSLR cameras. No adapter is needed, as would be the case with 1.25” filters. And if you are into astrophotography, that’s the way to go.

It comes at a price, though. The L-Enhance filter costs about ten times the price of our top pick so that you can buy an entry-level telescope and a pack of accessories for its price. On the other hand, if you don’t settle for half-measures and want the best thing the money can buy, this is a decent option.

  • Accurate filtering;
  • Performs great on 2” eyepieces;
  • Great construction;
  • Compatible with eyepieces and cameras (with an adapter);
  • Helps create fantastic astrophotos.
  • Has no 1.25” version;
  • Expensive!

4. ICE 1.25” LiPo Filter for Telescope: the Dark Horse

Key characteristics

  • Brand:‎ ICE
  • Material: Optical Glass, Plastic
  • Photo Filter Effect Type: Enhancing
  • Size: 1.25 inch
  • Targets: reduces light pollution for clear night sky viewing; blocks sky glow without affecting the entire color spectrum

The distributor named Desmond-ICE behind this filter proudly says that it’s from Oregon. Yet if you don’t want to reveal where your goods come from, it only means one thing. And it’s not about the origin (Svbony and Gosky aren’t afraid to reveal their Chinese roots) but rather about uncertainty about the products. Luckily, this 1.25” filter is not the case.

The “LiPo” in the name stands not for lithium-ion polymer (how do you put a battery in a filter?) but for more relevant “light pollution.” As for me, I’d avoid this misleading abbreviation, especially if it’s written on the ring. You have to get used to it. However, the ring is rather solid and durable, easy to mount on eyepieces and DSLR adapters.

As for the filter itself, it’s a little… well, the manufacturer does not reveal the chart that is easy to find for our other contenders. The reason may be that it’s positioned as a versatile one, not only as a light pollution filter (as the name suggests) but also as a one that reduces the moon glow. Apparently, it does not truly excel at any of these features, providing an effect noticeable but not stunning.

And this is where another advantage works: stackability. With both a male and a female connector on the ring, you can use an extra moon or light pollution filter on it, thus amplifying its effect of it plus adding a bit of the other impact. It’s also said to work wonders with color filters, but I did not try it. With a polarizing filter by the same brand, though, it creates a great duo. Even by itself, accompanied by a decent telescope and/or camera, it does quite a good job.

As for the price, it’s usually about $20 or slightly less than that. Even more affordable than our top pick, but don’t expect wonders. Like many other affordable solutions, it may underperform if you don’t know how to make it work decently.

  • Works as both moon and light pollution filter;
  • Quite versatile;
  • Can be used with other filters;
  • More than reasonable price.
  • The wavelength chart is not included;
  • The effect is often rather small.

5. SVBONY 1.25” Moon Filter: Watch the Moon

Key characteristics

  • Brand:‎ SVBONY
  • Photo Filter Thread Size: 31.7 Millimeters
  • Material: Optical Glass, Plastic, Metal
  • Photo Filter Effect Type: Enhancing
  • Size: 1.25 inch
  • Targets: enhances contrast when observing brighter objects

Moon filters are well different from your regular light pollution filter. They are meant primarily to reduce the moon glow you can see when watching it with the naked eye. No wonder Svbony, the manufacturer of our top pick, also has a moon filter meant to reduce it and see our natural satellite in all its glory.

The glass in this filter looks blue or violet, depending on the angle. The wavelengths it filters are rather sophisticated, the chart showing multiple ups and downs in the range of 300-900 nm. It also has a generic light pollution filtering effect, though not as focused as that of our top pick. The manufacturer acknowledges that and warns that this is not a nebula filter. The inscription on the metal ring simply says “Moon.”

You can also try using it to watch other planets, though it will obviously have less effect than colored special filters. Nevertheless, if you want to see brighter objects in the darker sky and more details on the Moon’s surface, this is the one you need. As for colored filters, you can apply them too. Unlike our top pick, this one is double-threaded, with both female and male connectors, so other filters can be stacked upon it.

The price of this filter is as modest as you might expect, well under $20. And for this price, it can’t get any better.

  • Reduces moon glow;
  • Well-built;
  • Shows details on the Moon’s surface well;
  • Can be used with other filters;
  • Very affordable.
  • Not the best for light pollution.

Buyer’s guide

Given all this, how do you choose your best filter? You need to consider the factors before choosing the filter light pollution to see stars, planets, and nebulae in the best possible way.

Types of Light Pollution Filters

Traditionally, three types of light pollution filters are named:

  • Broadband. These usually pass the light in a 50+ nm band, including H-beta (486nm) and OIII (496nm and 501nm) lines. Though they also let much pollution through, they provide natural colors.
  • Narrowband. These only let through a band of about 30 nm, including the same critical wavelengths. With this light pollution filter, astrophotography becomes a pleasure due to its strength. But these only can display a green and blue light.
  • Line filters. These are the most powerful, as they only let through one or several spectral lines. Being the most powerful, they also make the sky look the least natural.

These differences are caused by the nonlinear nature of the distortion caused by light pollution. It lies within a certain range, but the parameters may differ. One light pollution filter for telescope may perform perfectly on your roof and poorly in another district because of differences in lights, weather, and any factor that impacts the visibility.

Obviously, broadband filters are the most affordable, and our top picks are exactly this type, despite the nonlinear graphs of their parameters. It takes more art and precision, and better materials and more precision to make a narrowband or a line filter; that’s why these are more expensive. But with the best light pollution filter telescope, power doubles, so choose your priorities!

How Light Pollution Filters Work

The anthropogenic light pollution caused by artificial lighting is the most prominent at certain wavelengths. These can be named mostly because most modern lights utilize mercury and sodium, emitting lights of certain wavelengths. For mercury, this range lies between 405 and 578nm, with peaks at 436 and 546nm; for sodium, it’s 570, 583, and 600nm. As you see, these parameters overlap a bit, plus they don’t have an equal impact, so the approach by filter makers can differ too.

Filtering these out, we get a more realistic picture of the sky. As you see, the filters work a similar way: highlight the useful wavelengths and reduce the obstacles emitted by artificial light sources. For example, our top pick highlights wavelengths 465-515 nm while those around it are lowered or filtered out.
As a result, we see the sky as if these artificial lights never existed. In the perfect world, there is. In the real one, you may need to sacrifice all the colors but blue and green or suddenly discover your broadband filter is so broadband that it has nearly zero advantages.

Which Size Filter Do I Need?

It depends on the eyepiece you use. The most popular eyepieces in amateur astronomy have diameters of 1.25” and 2”. The former is great for using directly with eyepieces, fitting the most popular types. To use them with DSLR cameras, though, you will need to use a special adapter because this type of filter is too small.

As for 2” filters, they are meant for 2” eyepieces. They can be used directly with DSLR cameras, connecting directly to its lens. This grants incredible richness of combinations: choose the body and the lens you like, then connect the right filter to it. After it, connect it to your telescope eyepiece and make incredible pictures of the sky. It gets even richer if you use filters with double threading so that you can stack them one on one.

a lot of light filters

FAQ on Light Pollution Filters for Telescopes

Mankind got used to asking itself questions while staring at the sky. Let’s address some of them now, at least those that can be answered. By the way: 42. If that’s not the answer you’ve been looking for, let’s proceed.

What can be used in a telescope to eliminate light pollution?

There are two ways. The first: use a filter. The second: move to a place where light pollution is minimal or absent at all. Scientists prefer the second way, but if you cannot afford to build your own Keck on Mauna Kea, filters are the way to go.

Do you need a light pollution filter for astrophotography?

Yes, photos are much better with the right filter. First, make sure your camera and telescope are compatible, and if not, think about buying an adapter.

What is Light Pollution?

It’s the light emitted by artificial sources and then transmitted by microparticles in the atmosphere, thus forming a parasite background that makes space objects vague or invisible.

Filter the Night!

As you see, a light pollution filter is probably the first thing to get after you get your telescope. With it, you can enjoy the night sky and take stunning photos. While our top pick by Svbony may be a great one to get familiar with the class, given its price, you may find it so decent that buying others will make sense of pure curiosity.

What can you tell us about your experience with light pollution filters? Got one or more? Which one would you recommend? Share your impressions in the comments! And if you have made an astrophoto you can’t keep to yourself, we’d like to see it too!

About Michael Oliver Barlow

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