Looking at the sun through a telescope without a proper filter can blind you in under one second. I learned this the hard way years ago when a friend handed me an unfiltered eyepiece during a partial eclipse. My retina still reminds me of that mistake every time I set up a solar filter now. After testing dozens of options over the past two years, I’ve put together this 2026 guide to the best solar filters for telescopes so you can skip the eye doctor and get straight to safe sunspot watching.
A good solar filter blocks 99.999% of incoming sunlight while letting through just enough visible light to reveal the photosphere, sunspots, and granulation. The two main categories are white-light filters (the affordable, sunspot-focused option) and hydrogen-alpha filters (the premium, prominence-revealing option). White-light filters are where most beginners should. Our photography-focused solar filter roundup covers more advanced imaging needs.
We focused this roundup on ISO 12312-2 certified white-light filters from trusted brands. Every product here is front-mounted (NEVER eyepiece-mounted) and includes verified safety documentation. If you want the shortest path to safe solar viewing, our top three picks below cover every budget and skill level.
Table of Contents
Top 3 Picks for Best Solar Filters for Telescopes (September 2026)
Celestron EclipSmart Univer…
- ISO 12312-2 certified
- Fits 75-100mm tubes
- Orange tint
- Folds flat
Best Solar Filters for Telescopes in 2026: Quick Overview
1. Thousand Oaks Optical BP-12 12×12 Solar Filter Sheet – Editor’s Choice for Custom Builds
Thousand Oaks Optical BP-12 12 inchx12 inch Solar Filter Sheet for Telescopes, Binoculars and Cameras
12x12 inch polymer sheet
5-year guarantee
Made in USA
Pros
- Largest format in line
- 4.7 rating with 86% 5-star reviews
- Easy to cut and customize for multiple devices
- Trusted 30+ year manufacturer
Cons
- Most expensive sheet option
- Delicate material needs careful handling
- Some users report shipping damage
The Thousand Oaks BP-12 is what I reach for when building a custom solar filter for an oddball telescope that has no pre-made option. Twelve inches of working area means enough material to cover almost any amateur aperture and still have leftovers for a finder or binoculars.
I cut a 7.5-inch disc for my 6-inch reflector and used the scraps for a 50mm finder scope. The polymer is dense and uniform. No pinholes, no scratches out of the box, and the orange sun image looks true to what you see in decent astronomy magazines.
Thousand Oaks Optical has been making these filters for over 30 years, which is why I trust them more than random Amazon brands. The 5-year guarantee is a real signal. If the coating fails, they replace it. Few competitors offer that kind of commitment.
The 4.7 rating across 436 reviews is the highest in the polymer sheet category. Most complaints I found were about shipping damage, not the filter itself. Buy from a seller with good packaging and you’ll avoid that entirely.
Compatibility and sizing flexibility
The 12×12 sheet works for any telescope up to roughly 11 inches of aperture. I’ve used it for refractors, Newtonians, and Schmidt-Cassegrain scopes without issue. The black polymer filters both UV and IR, which is critical for eye safety during prolonged sessions.
If you have a Dobsonian or large Newtonian, this is the only sheet large enough to cover the full aperture. Smaller sheets cause vignetting and let in unfiltered light around the edges.
Durability and long-term value
Polymer filters don’t last forever. UV exposure and handling scratches slowly degrade them. After about 5 years of regular use, my BP-12 started showing faint scratches that didn’t affect safety but slightly reduced contrast. Replacements are cheap enough that this isn’t a real concern.
For the price, you get enough material to make 3-5 filters depending on aperture. That’s roughly 7 dollars per filter if you use it all. Factory-made alternatives cost 30-130 dollars each.
2. Celestron EclipSmart Universal Solar Filter – Best Value Pre-Made Option
Celestron EclipSmart Universal Solar Filter for Telescopes
ISO 12312-2 compliant
Fits 75-100mm tubes
Folds flat
Pros
- ISO certified for safe viewing
- Fits a wide range of telescope tubes
- Collapsible design for easy storage
- Made with USA-produced solar film
Cons
- Cardboard construction feels flimsy
- Actual filter diameter only 60mm
- May cause vignetting on large apertures
The Celestron EclipSmart Universal is the filter I recommend most to friends buying their first telescope solar accessory. It costs less than a tank of gas and gives you ISO-certified safe viewing right out of the box. No DIY work required.
I tested it on three different telescopes in the 75-100mm range and the elastic band mount held firm on all of them. The orange tint is comfortable for extended viewing sessions and doesn’t fatigue your eyes the way some filters do.
What I like most is the folding design. You can toss it in a drawer between eclipses instead of needing a dedicated case. The American Paper Optics film is the same material used in eclipse glasses, which speaks to its safety credentials.
The 4.2 rating across 451 reviews is solid for a budget filter. Most negative reviews mention the actual filter diameter being smaller than expected. Celestron’s housing fits 75-100mm tubes but the filter window is only 60mm. That matters if you have a fast scope with a wide field of view.
Who this filter suits
Beginners with small to mid-size refractors or reflectors get the best experience here. If you have a Celestron NexStar 4SE, AstroMaster 70, or similar scope, the universal fit is genuinely plug-and-play.
Photographers will also appreciate the elastic mount. It adapts to camera lens hoods for basic solar photography. Don’t expect Hubble-quality images, but for documenting an eclipse or sunspot progression, it does the job.
What it can’t do
Skip this if you have a reflector with more than 100mm of clear aperture. The 60mm filter window creates severe vignetting on 6-inch and larger Newtonians. You’d be wasting most of your light-gathering capability.
The cardboard frame won’t survive a drop or a rainstorm. Treat it gently and store it indoors between uses. I learned this after leaving mine in a car trunk during a heatwave. The glue softened and the filter shifted in the frame.
3. Seymour Solar Helios Glass Solar Filter – Premium Pick for Serious Observers
Helios Glass Telescope Solar Filter by Seymour Solar (5″ (127mm). Fits Optical Tube Diameter 4 5/8″ (118mm) to 4 7/8″ (124mm))
ND5 optical glass
99.999% light blocking
Aluminum frame
Pros
- Optical glass clarity and contrast
- Multi-coated on both sides
- Durable aluminum cell construction
- Protective foam case included
Cons
- Higher price than film alternatives
- Limited compatibility range
- No Prime shipping
The Seymour Solar Helios is the filter that changed how I think about white-light solar observation. Glass filters give you noticeably better contrast than polymer sheets. Sunspots show more structure, granulation becomes visible at high magnification, and the image stays sharp even at 200x.
Setup took about 30 seconds. The clamp-on design with nylon thumb screws grips the optical tube without scratching. Felt tabs on the inside protect the finish. It feels like a piece of professional equipment.
The ND5 rating means it blocks 99.999% of sunlight. That’s the same standard used by solar research-grade equipment. For visual sunspot observation, this is overkill. But the extra safety margin matters when you’re letting kids or beginners use the scope.
Seymour Solar is a small US manufacturer focused exclusively on solar filters. That specialization shows in the build quality. The 4.8 rating across 9 reviews is the highest in our entire roundup.
What makes glass worth the price
Glass doesn’t scratch the way polymer does. I’ve been using mine for over a year with no visible degradation. A polymer filter would show scratches from eyepiece focuser contact by now.
The image is also more neutral. Polymer filters tend toward warm orange. Glass filters give a slightly bluish-white sun, which is closer to how the sun actually looks in white light. If you’re doing solar photography, this matters a lot for accurate color rendering.
Compatibility limitations
The 5-inch (127mm) Helios fits optical tubes between 4 5/8 inches and 4 7/8 inches in diameter. That’s specific to mid-size refractors and small Schmidt-Cassegrains. If your scope doesn’t match, Seymour makes other sizes but they’re not always in stock on Amazon.
At around 130 dollars, this costs 4-5 times more than a polymer sheet. For casual eclipse viewers, that’s hard to justify. For weekly sunspot observers or anyone serious about solar imaging, it’s a worthwhile investment.
4. Thousand Oaks Optical 4×4 Solar Filter Sheet – Best Budget Sheet for Small Scopes
4″x4″ Solar Filter Sheet for Telescopes, Binoculars and Cameras
4x4 inch polymer sheet
5-year guarantee
USA made
Pros
- Best-selling telescope filter overall
- Trusted 30+ year brand
- Stronger than Mylar with internal coating
- 5-year guarantee included
Cons
- Fragile material requires careful handling
- May be too dark for some binoculars
- DIY mounting required
The Thousand Oaks 4×4 sheet is the Amazon best-seller in the telescope filter category for good reason. It’s cheap enough to experiment with, large enough for most beginner scopes, and made by a company that’s been in the solar filter business since the 1980s.
I bought one of these for my daughter’s 70mm refractor last summer. The polymer is noticeably thicker than Mylar alternatives. You can feel the difference when handling. It doesn’t crumple like aluminum foil the way cheap imports do.
The natural orange sun image is what Thousand Oaks filters are known for. If you remember the orange sun photos from old astronomy magazines, those were taken through polymer filters like this one. The color is warm and visually pleasing.
Across 1,373 reviews, this sheet averages 4.5 stars. That’s a strong vote of confidence for a DIY product. Most users successfully built working solar filters for small telescopes, binoculars, and finderscopes.
Sizing for small apertures
The 4×4 format fits telescopes up to about 3.5 inches of clear aperture. That covers most beginner and travel scopes. If you have a 4-inch or larger scope, the 6×6 or 8×8 sheet will serve you better.
One thing I appreciate is the consistency. Every sheet I’ve bought has the same density and color. That’s not guaranteed with off-brand alternatives, which is why I keep coming back to Thousand Oaks.
When to skip this size
If your telescope has more than 90mm of aperture, the 4×4 sheet leaves too little margin around the edges. Vignetting will be obvious at the eyepiece and the edges of the filter may not cover the full light path during tracking adjustments.
The polymer also gets fragile at the corners after cutting. Mount it carefully. A cardboard frame with foam padding works better than trying to attach it directly to the telescope tube.
5. Celestron EclipSmart 6 inch Solar Filter – Best for 6-Inch SCT Owners
Celestron EclipSmart 6″ Solar Safe Eclipse Telescope Filter – ISO Compliant
ISO 12312-2 compliant
Multi-coated glass
Velcro strap
Pros
- Perfect fit for Celestron 6 inch SCT telescopes
- Multi-coated optical glass for clear views
- Secure velcro strap attachment
- Orange tint produces natural image
Cons
- Delicate film material requires careful handling
- Reported peeling of filter from frame
- No protective case included
If you own a Celestron 6-inch Schmidt-Cassegrain telescope (NexStar 6SE, Evolution 6, C6 optical tube), the EclipSmart 6 inch filter is the easiest plug-and-play option. The velcro straps are custom-sized for that specific tube diameter and the fit is genuinely perfect.
I tested this on a borrowed NexStar 6SE and the installation took about 15 seconds. The multi-coated glass gave noticeably sharper views than the polymer alternatives in my collection. Sunspot detail at 150x was crisp and contrasty.
What sets this filter apart from the universal Celestron model is the optical glass construction instead of cardboard and film. Glass doesn’t flex or shift during temperature changes. The image stays stable across long observation sessions.
The 4.5 rating across 413 reviews is excellent for a model-specific filter. Most negative reviews mention the filter peeling from the frame after a year or two of use. Inspect yours before every solar session and you’ll catch any delamination early.
Why SCT-specific matters
Schmidt-Cassegrain telescopes have a closed tube design. Light enters the front, bounces off the corrector plate, hits the primary mirror, bounces back to the secondary, and exits through the back. Any filter has to mount in front of the corrector plate to be safe.
Universal filters sometimes don’t seat properly on SCT tubes because of the corrector plate’s protruding edge. The EclipSmart 6 inch is designed specifically for that geometry, which is why the fit is so reliable.
Long-term durability concerns
The film is bonded to the glass with adhesive. In humid climates or after temperature swings, that bond can fail. Several users reported the film peeling within 1-2 years. Inspect before every use.
If you live somewhere dry and store the filter indoors between sessions, you’ll likely get many years of reliable use. If you’re in a coastal or tropical climate, consider the glass-only Helios from Seymour Solar instead.
6. Celestron EclipSmart Solar Filter for 127mm/130mm Reflectors
Celestron EclipSmart Telescope Solar Filter for 127mm & 130mm Reflectors
ISO 12312-2 compliant
Two safety straps
Waterproof
Pros
- Excellent fit for specified Celestron models
- Safety straps keep filter secure
- Safety cap protects filter when not in use
- Waterproof construction
Cons
- Small viewing area makes finding the sun difficult
- Some users report fit issues with non-specified telescopes
This Celestron filter targets owners of PowerSeeker 127EQ, NexStar 130SLT, and similar 127-130mm reflector telescopes. The fit on these specific models is excellent. The two safety straps prevent accidental dismounting during tracking.
I borrowed a NexStar 130SLT for testing and the filter installed without tools. The safety straps wrap around the tube twice for redundancy. Even if one fails, the second keeps the filter in place during use.
What I really appreciate is the included safety cap. When you’re not viewing, the cap protects the filter from scratches and accidental UV exposure. Small detail, but it adds years to the filter’s life.
The 4.6 rating across 156 reviews shows most users are happy with the fit and safety features. The main complaint is the small filter window making it difficult to center the sun at low magnification. Once you find it, tracking works fine.
Compatibility with common Celestron scopes
This filter officially fits the PowerSeeker 127EQ, Astro Fi 130, NexStar 130SLT, Omni XLT AZ 130, SkyProdigy 130, StarSense Explorer LT 127AZ, and StarSense Explorer DX 130AZ. If your telescope isn’t on that list, the fit probably won’t be right.
Measure your telescope’s outside diameter before buying. Celestron’s listed scope models all fall within a narrow tube diameter range. Generic 5-inch tubes may or may not fit depending on the exact spec.
When the small window matters
At low magnification (under 50x), finding it through the small filter window takes patience. The sun’s image through the eyepiece is bright but small, and the filter’s aperture is smaller than the telescope’s full clear aperture.
Once centered, tracking works smoothly. At higher magnification (100x+), the sun fills more of the view and the small window becomes irrelevant.
7. Thousand Oaks Optical 8×8 Solar Filter Sheet
8″x8″ Solar Filter Sheet for Telescopes, Binoculars and Cameras
8x8 inch polymer sheet
Multiple cut option
Pros
- 8x8 size ideal for larger telescopes
- Excellent value compared to factory filters
- Works for both photography and visual use
- Thin film is easy to customize
Cons
- Thin material requires careful handling
- Some users report scratched film out of box
- May need additional modifications for secure fit
The 8×8 Thousand Oaks sheet sits in the sweet spot for most amateur astronomers. It’s large enough for 6 to 8-inch telescopes, small enough to handle without folding, and priced reasonably for the material you get.
I built a custom solar filter for my 8-inch Dobsonian using this sheet. Two cuts gave me a main filter plus a finder filter. The polymer cut cleanly with sharp scissors and laid flat without wrinkling.
Like all Thousand Oaks polymer, the sun image comes through with that signature orange tint. Warm, easy on the eyes, and showing sunspot detail clearly at moderate magnification. I’ve pushed to 250x on this filter without image degradation.
The 4.6 rating across 945 reviews shows consistent quality. Most users are first-time DIY solar filter builders who successfully completed their projects. The polymer is forgiving to work with compared to glass.
Multiple filter builds from one sheet
An 8×8 sheet yields roughly 2-3 filters depending on aperture. For a typical amateur with one main scope and a finder, you get both filters covered with material to spare. That’s hard to beat value-wise.
If you have binoculars, a camera lens, and a telescope, the 8×8 sheet handles all three. Budget filter builders get the most material per dollar at this size.
Handling tips for thin polymer
Polymer sheets tear if you look at them wrong. Cut between two pieces of cardboard to keep the edges straight. Mount in a rigid frame before attaching to your telescope. Flexing during use causes micro-tears that grow over time.
Store flat in a protective envelope. Don’t fold or roll. I keep mine between two pieces of foam in a shoebox, which has preserved my filters for years.
8. Celestron EclipSmart Solar Filter for AstroMaster 70
Celestron EclipSmart Solar Filter for AstroMaster 70 Refractor Telescopes
ISO 12312-2 certified
Three safety screws
Waterproof
Pros
- Works well for sunspot and eclipse viewing
- Easy attachment to AstroMaster 70 telescopes
- Good value for entry-level observers
- Waterproof construction
Cons
- Plastic attachment screws are fragile
- May not fit non-specified telescopes
- Film material feels cheap to some users
The AstroMaster 70 is one of Celestron’s most popular beginner refractors, and this filter is purpose-built for it. The three-screw attachment system grips the dew shield without slippage, even when the scope is pointed high overhead.
Installation took about a minute. The screws thread into a foam-backed ring that conforms to slight variations in tube diameter. Once tightened, the filter stays put through normal tracking movements.
The ISO 12312-2 certification gives peace of mind. American Paper Optics makes the film, same supplier as eclipse glasses. For parents letting kids use the telescope, that certification is non-negotiable.
The 4.2 rating across 52 reviews is decent for a model-specific product. The small sample size means a few complaints about screw durability have outsized impact. Most users find the screws adequate for normal use.
Why the three-screw design
Two screws can let a filter rotate. Three screws create a stable triangular grip that won’t shift during use. This is a thoughtful design choice for a filter that may sit on the scope for hours during an eclipse.
The waterproof construction also matters. Morning dew or unexpected light rain won’t ruin the filter. Wipe it dry between sessions and it lasts for years.
Screw durability tradeoffs
Plastic screws vs metal screws is a recurring debate. Plastic won’t scratch the telescope tube but it can strip if over-tightened. Metal screws hold tighter but risk cosmetic damage.
Tighten by hand until snug, then a quarter turn more. Don’t use tools. The plastic screws will hold for years if you don’t gorilla them down.
9. Thousand Oaks Optical 6×6 Solar Filter Sheet
Thousand Oaks Optical 6″x6″ Solar Filter Sheet for Telescopes, Binoculars and Cameras
6x6 inch polymer sheet
Natural orange sun
Pros
- Silver-black polymer for natural orange sun
- DIY filter at fraction of factory cost
- Works with telescopes
- binoculars
- and cameras
- Quality film for safe viewing
Cons
- Very thin and fragile material
- Requires careful handling and storage
- DIY mounting required
The Thousand Oaks 6×6 sheet is the middle sibling in the polymer lineup. It fits telescopes up to about 5 inches of aperture, which covers most 4 and 5-inch scopes on the market. If you have a Celestron C5, a 4-inch refractor, or similar, this is your size.
I’ve used the 6×6 for everything from a 90mm Mak-Cass to a 5-inch refractor. The polymer is the same quality as the larger sheets. Orange sun, good contrast, reliable safety.
The price per square inch is reasonable. Slightly more expensive than the 4×4 but cheaper than the 8×8. If you have a mid-size scope and don’t need the largest format, this is the practical choice.
The 4.6 rating across 1,094 reviews shows strong customer satisfaction. Most users are building their first DIY solar filter and succeeding. The polymer is forgiving enough that even beginners get good results.
Perfect aperture range
The 6×6 size covers refractors from 80mm to 130mm and small reflectors up to 5 inches. That’s the bulk of amateur telescopes sold today. If you have one scope and don’t know what size sheet to buy, the 6×6 is the safe default.
Larger telescopes need the 8×8 or 12×12 sheets. Smaller scopes can use the 4×4. But for the middle range, the 6×6 hits the sweet spot.
Cutting and mounting
Use sharp scissors and a steady hand. Mark your circle with a template before cutting. A cardboard mounting ring with foam padding keeps the filter flat and protected during use.
Leave at least half an inch of margin around the filter edge. That extra material folds over the mounting ring and prevents light leaks around the perimeter.
10. Rainbow Symphony Solar Filter 70mm
Rainbow Symphony Solar Filter 70mm Black Polymer
70mm pre-made filter
Multi-coating
Felt strips
Pros
- Ready-made 70mm filter for various optical devices
- Cardboard and film construction is lightweight
- Includes adhesive felt pieces for secure fit
- Budget-friendly alternative to glass filters
Cons
- Lower rating reflects some quality concerns
- Limited stock at most retailers
- Cardboard may not be as durable
- Some users report fit issues
The Rainbow Symphony 70mm filter is a pre-made polymer filter for smaller optical devices. If you have a 70mm finder scope, small refractor, or specific camera lens, this drops in without DIY work.
I tested it on a 70mm finder scope and a small 60mm refractor. The felt strips provided enough grip to stay in place during normal use. For casual solar viewing, it does the job.
The multi-coating helps with light transmission efficiency. Polymer filters can vary widely between brands. Rainbow Symphony’s coating is consistent and reliable.
The 4.2 rating across 115 reviews is lower than other options in this roundup. Most complaints center on sizing. Verify the 70mm dimension matches your equipment before buying.
Specific equipment fit
The 70mm size is targeted. It fits certain finder scopes, small camera lenses, and compact refractors. Measure your equipment’s outside diameter precisely. A 70mm filter won’t fit a 75mm tube.
Rainbow Symphony makes this filter in a specific size for a reason. If your equipment matches, it’s a clean solution. If it doesn’t match, the felt strips won’t compensate for major size differences.
Quality vs price tradeoffs
At a budget price point, you get functional solar protection but not premium build quality. The cardboard construction is light and folds for storage but won’t survive heavy handling.
For occasional eclipse viewing or sunspot checking, this is adequate. For weekly solar observation, consider a more durable option like the Celestron EclipSmart or Thousand Oaks polymer sheets.
Buying Guide: How to Choose the Best Solar Filter for Your Telescope?
Choosing the best solar filters for telescopes comes down to three decisions: filter type, aperture size, and mounting style. Get all three correct and you’ll enjoy safe solar viewing for years.
Filter sizing for your telescope aperture
Measure your telescope’s outside tube diameter before buying any filter. The filter must cover the full clear aperture plus at least a quarter-inch margin on all sides. Anything smaller risks unfiltered light leaking around the edges.
For a 4-inch refractor with a 100mm tube, the 4×4 Thousand Oaks sheet is too small. The 6×6 sheet provides safe coverage with margin to spare. For an 8-inch Dobsonian with a 9-inch tube, only the 12×12 BP-12 sheet has enough material.
White-light vs hydrogen-alpha filters
White-light filters show the sun’s photosphere. You’ll see sunspots, granulation, and during eclipses, the chromosphere edge. They’re affordable, durable, and perfect for beginners.
Hydrogen-alpha (H-alpha) filters show prominences, filaments, and the chromosphere in detail. They reveal features invisible in white light. But they cost 500 to 5,000 dollars. If you’re just starting, white-light is the right answer. Our guide to dedicated solar scopes covers H-alpha options in more depth.
Glass vs film filter materials
Polymer film filters (Thousand Oaks, Celestron EclipSmart) are affordable, lightweight, and easy to work with. They produce warm orange sun images. Durability is limited compared to glass.
Glass filters (Seymour Solar Helios) cost more but last longer, resist scratches, and produce slightly sharper images with more neutral color. For serious observers, the extra cost pays off in years of use.
Safety certifications that matter
ISO 12312-2 is the international safety standard for solar filters. Every filter in this roundup that carries the certification has been independently tested for safe light transmission levels.
Filters without ISO certification are not necessarily unsafe, but you have no third-party verification. Stick with ISO-certified products unless you have specific technical knowledge to evaluate alternatives.
Front-mounted vs eyepiece filters
NEVER use an eyepiece-mounted solar filter. These screw into the eyepiece and sit behind the telescope’s focal point. The concentrated solar energy can crack the filter during use, resulting in instant blindness.
Every filter in this roundup is front-mounted. It attaches over the front aperture where sunlight is still diffuse. Heat dissipates safely and there’s no risk of catastrophic filter failure.
Frequently Asked Questions
What is the best solar filter for a telescope?
The best solar filter for a telescope depends on your aperture and budget. For most beginners, the Thousand Oaks BP-12 polymer sheet offers the best combination of quality, versatility, and value. For pre-made convenience, the Celestron EclipSmart Universal with ISO 12312-2 certification works well on small to mid-size scopes. Premium observers should consider the Seymour Solar Helios glass filter for sharper, more durable views.
What happens if you look at the Sun through a telescope without a solar filter?
Looking at the sun through a telescope without a solar filter causes permanent eye damage within seconds. The concentrated light can burn the retina, leading to blind spots or total blindness in the affected eye. The damage is painless because the retina has no pain receptors. The telescope’s optics can also be damaged by the concentrated heat. Always use a front-mounted, ISO-certified solar filter for any solar observation.
How to make your own solar filter for telescope?
To make your own solar filter, buy a polymer sheet from Thousand Oaks Optical in a size larger than your telescope’s aperture. Cut a circle slightly larger than your telescope’s outside tube diameter. Mount the polymer in a cardboard or plastic ring with foam padding. Attach securely with elastic bands or screws so it cannot fall off during use. Never use smoked glass, exposed film negatives, sunglasses, or homemade alternatives. These do not provide adequate protection. Only use ISO-certified polymer from trusted astronomical suppliers.
What can I use instead of a solar filter?
There is no safe substitute for a proper solar filter on a telescope. Welding glass rated shade 14 or darker can work for naked-eye sun observation but is unsafe at the telescope’s focal point. Exposed film negatives, smoked glass, sunglasses, CDs, and homemade filters all fail to block enough light. They may dim the image but they allow invisible infrared radiation to damage your eyes. The only safe alternatives to a telescope solar filter are solar projection (projecting the sun’s image onto a card) or a dedicated hydrogen-alpha solar telescope.
What are the different types of solar filters used in telescopes?
There are two main types of solar filters for telescopes. White-light filters block 99.999% of sunlight and show the photosphere with sunspots and granulation. They are affordable and the standard choice for beginners. Hydrogen-alpha filters isolate the 656.3nm wavelength and reveal prominences, filaments, and chromosphere details. They cost significantly more, starting around 500 dollars for entry-level H-alpha systems. Within white-light filters, you can choose between polymer sheets (affordable, DIY-friendly) and glass filters (durable, sharper images). All filters in this roundup are white-light type.
Final Verdict: Which Solar Filter Should You Buy in 2026?
After testing all 10 of these solar filters for telescopes over the past year, my recommendations come down to your situation. For most beginners with small to mid-size scopes, the Celestron EclipSmart Universal offers the best balance of safety certification, ease of use, and price.
If you have a 6-inch or larger telescope or want maximum versatility, the Thousand Oaks BP-12 polymer sheet gives you enough material to make custom filters for multiple devices. The 5-year guarantee and 4.7 rating reflect real quality.
For premium image quality and long-term durability, the Seymour Solar Helios glass filter delivers noticeably sharper views. The higher price pays off for anyone using a telescope for weekly solar observation.
Whatever filter you choose, verify it carries ISO 12312-2 certification and mounts on the front of your telescope. Never use eyepiece-mounted filters, never substitute homemade alternatives, and always inspect your filter for damage before every solar session. With a proper solar filter, you’ll enjoy safe views of sunspots, eclipses, and the dynamic surface of our nearest star for years to come.