Looking straight at the Sun through a telescope without a certified filter in front of the objective can cause permanent eye damage in a fraction of a second, because the instrument concentrates sunlight far beyond what the eye was designed to handle. That single fact shapes every recommendation in this roundup of the best solar filters for telescopes available now in 2026.
What I set out to do here is narrow and practical. I compared ten filters that cover the three ways people actually buy them: a sheet of film they cut and tape into their own holder, a fold-over universal filter for small tubes, and a rigid pre-mounted cell made for a specific telescope. Each entry below states the material, what it fits, how the Sun looks through it, and where owners report problems.
Two things are constant across the whole list. Every filter here sits at the front aperture, never at the eyepiece, and the ones sold as ready-made claim compliance with ISO 12312-2, the international standard for filters used to view the Sun directly. If you are still choosing an observing setup rather than a filter, the same measurement logic we use for the fitment section applies to the other hardware on our site, including our picks for the best solar lights for walkways if you want a night-sky-safe path to your observing spot.
What follows is a list, not a ranking by review count alone. Several of these are near-identical sheets of black polymer film, so I have given each one a distinct job: the sheet that fits the most gear, the sheet that is easiest to trim, the sheet that yields the most finished filters, and the sheet that looks flattest through the eyepiece.
Table of Contents
Top 3 Best Solar Filters for Telescopes (October 2026)
These three cover the most common situations, and they deliberately use different approaches so you are comparing ownership styles rather than three variations of the same object.
Thousand Oaks BP-4 Sheet
- Genuine Thousand Oaks black polymer film
- Cut to size for any aperture
- Works on telescopes
- binoculars and cameras
Celestron EclipSmart 8 inch
- ISO 12312-2:2015(E) compliant
- American Paper Optics film
- Two hook and loop straps hold it to the objective
Thousand Oaks BP-6X6 Sheet
- 6 inch by 6 inch black polymer sheet
- Covers mid aperture tubes
- No cutting tools needed for most scopes
All 10 Best Solar Filters for Telescopein in 2026
The table below lists every filter in this roundup with the one specification that decided its place. Full discussion of each one follows.
| Product | Specifications | Action |
|---|---|---|
| Thousand Oaks BP-4 4×4 Filter Sheet |
|
Check Latest Price |
| Thousand Oaks BP-6X6 6×6 Filter Sheet |
|
Check Latest Price |
 Thousand Oaks BP-8 8×8 Filter Sheet |
|
Check Latest Price |
| Celestron EclipSmart 8 inch SCT Filter |
|
Check Latest Price |
 Celestron EclipSmart Universal Filter |
|
Check Latest Price |
 Thousand Oaks BP-12 12×12 Filter Sheet |
|
Check Latest Price |
 Celestron EclipSmart 127mm and 130mm |
|
Check Latest Price |
 Astromania 100mm Metal Cap Filter |
|
Check Latest Price |
 Rainbow Symphony 101mm Black Polymer |
|
Check Latest Price |
 Celestron EclipSmart AstroMaster 70 |
|
Check Latest Price |
Solar Filter Safety: The Rule That Overrides Everything Else
The filter must go on the front of the telescope, over the objective, before any sunlight enters the optical path. This is not a preference; it is the mechanism that keeps the Sun from being focused onto the eyepiece or onto your retina.
Filters that screw into or slide behind the eyepiece are dangerous. If the filter is not in place first, concentrated sunlight reaches the eye directly through the optics. Owners on r/telescopes describe this risk as the single most repeated warning in solar threads, and it is why every product in this roundup is described by where it attaches rather than by magnification.
Look for the ISO 12312-2 designation. That standard, referenced in its 2015 edition, covers filters intended for direct solar viewing. The four Celestron filters in this list and the Astromania metal cell all state compliance, and the Celestron models specify film made in the USA by American Paper Optics, a supplier recommended by NASA and the American Astronomical Society and independently tested by a third-party laboratory.
Two more habits keep you safe. Cover the front of the filter with your hand or a cap whenever the telescope is not pointed at the Sun, and remember that a finder scope is a telescope: a finder left unfiltered will show you an unsafe, undiminished solar image, which is how people accidentally aim an unfiltered instrument at the Sun.
Inspect the film before every single session, not just once a year. Owners on r/AskAstrophotography repeatedly report finding new pinholes and creases that were not there last time they looked. If you cannot see the surface clearly, replace the sheet rather than continuing.
1. Thousand Oaks BP-4 Filter Sheet – Most Reviewed, Most Flexible
4″x4″ Solar Filter Sheet for Telescopes, Binoculars and Cameras
Model BP-4, 4 inch by 4 inch black polymer sheet for telescopes, binoculars and cameras
Pros
- Largest review base in the group at more than 1300 ratings
- Filtering properties sit inside the substrate rather than on the surface
- One sheet covers finders
- binoculars
- scopes and telephoto cameras
- Five year guarantee from a maker of solar filters for over 30 years
Cons
- Thin film scratches easily
- Some owners find it passes more light than expected at high binocular power
- You have to build and tape your own holder
With 1,370 ratings averaging 4.5 stars and 74 percent of those ratings at the full five stars, this is the most heavily reviewed filter in the set, and the review volume is the reason I put it first. It is not the highest rated entry, and it is not the most refined, but nobody in this group has as much long-term owner feedback behind it.
I find this sheet most useful on the equipment that never gets its own filter. A finder scope, a pair of 50mm binoculars and a 300mm telephoto lens all need roughly the same treatment, and a 4 inch square produces usable pieces for all three. Larger objectives need more area, which is the reason the same manufacturer also sells this film in bigger sheets further down.
Manufacturer part number BP-4, listed dimensions 4 inch by 4 inch, polymer enclosure material, no coating. The physical item is thin and light, so it does not strain a small focuser or tip a lightweight mount.
The film is genuine Thousand Oaks Optical material, described by the maker as stronger than Mylar with the filtering properties held inside the substrate rather than coated on the surface. That construction is the reason a scratch across the face is less serious on this product than on a surface-coated film, though it is still not something to be casual with.
The one drawback buyers raise most is brightness at high power on binoculars. A handful of reviewers compare the view to eclipse glasses and find the sheet reads slightly lighter than expected, which matters more when two eyes and two objective lenses are in the path.
What to check before you cut into it
Measure the outside diameter of the tube, not the stated aperture, and leave a few millimeters of overlap for the tape that will hold the film on. Owners who skip this step end up with a filter that lets light in around the rim.
Cut on a clean, hard surface with a sharp blade, and support the film rather than letting it flex, because a crease in the middle of the aperture is the most common permanent flaw owners report.
Who should skip it
If you want a filter that arrives finished and needs no tools, or if you have a large aperture and no patience for making a proper cell, one of the ready-made options below fits better. The same applies if you are the sort of owner who will drop a case in the car; this sheet rewards a little care.
The manufacturer’s own warning applies: make sure the filter is well attached to the telescope or binoculars with tape so it cannot fall while observing.
2. Thousand Oaks BP-6X6 Filter Sheet – Budget Pick for Mid-Aperture Tubes
Thousand Oaks Optical 6″x6″ Solar Filter Sheet for Telescopes, Binoculars and Cameras
Model BP-6X6, 6 inch by 6 inch black polymer sheet listed for telescopes, binoculars and cameras
Pros
- Strongest sales rank in the group at number 11 in telescope filters
- Good value per usable area of any sheet reviewed
- One piece works for binocular pairs
- Large enough for most mid aperture refractors
Cons
- Bare film must be trimmed and secured before use
- Thinness makes creasing and scratching easy
This is the best solar filter for telescopes in this group if your aperture falls between about 90mm and 150mm and you do not want to build anything complicated. It holds 4.6 stars across 1,097 ratings, with 78 percent at five stars, and it sits at number 11 in the Telescope Filters category, the highest demand signal of any product here.
The 6 inch square is the most useful single size for a mixed equipment pile. It covers a 6 inch reflector front to front with a margin, gives you a binocular filter with room to spare, and still trims down for a 90mm refractor without wasting material.
Specifications list model BP-6X6, manufacturer part number BP-6X6, dimensions 6 inch by 6 inch, polymer material and a neutral density special effect. The product is supplied as one sheet.
Colour rendering is described in the listing as a natural orange, and that matches what owners describe for sunspots and granulation. Orange is the normal look for black polymer and aluminized film, and most visual observers come to prefer it once they know it is not a fault.
If you have never made a filter before, this is the size to practise on. Trim a square generously larger than the tube, tape it on with multiple strips across the rim, and check the view before you add magnification. The 4 inch sheet in the previous section serves the same purpose on smaller gear.
Sizing and mounting checks
Confirm the outer diameter of your tube and add roughly 10mm on each side for the tape border. A filter that ends exactly at the metal edge is the one most likely to shift during a session.
Check the film against a bright lamp before mounting. Wrinkles scatter light and reduce contrast; small pinholes do not reduce brightness enough for the eye to notice, which is exactly why they matter.
Where it falls short
It offers no protection for the effort of a bad trim. If you want a filter that clamps on, skip to the Astromania metal cap, which is the only rigid cell in this group. And if your tube is larger than 6 inches, the 8 inch and 12 inch sheets further down cover more aperture per cut.
Reviewers are consistent on one point: attach it firmly. The manufacturer warning in the listing says the same thing.
3. Thousand Oaks BP-8 Filter Sheet – Lightest Sheet, Multiple Filters Per Cut
8″x8″ Solar Filter Sheet for Telescopes, Binoculars and Cameras
Model BP-8, 8 inch by 8 inch black polymer sheet weighing 1.6 ounces
Pros
- Weighs only 1.6 ounces so it will not unbalance a light mount
- Large enough to cover an 8 inch tube in one piece
- Cuts down into several smaller filters for other gear
- Holds 4.6 stars across 947 ratings
Cons
- Requires fabrication and taping into a holder
- Thin polymer can crease and shows no wear indicator
The headline detail on this sheet is weight. At 1.6 ounces it is the lightest item in the entire roundup, which matters if you are hanging an 8 inch tube on an alt-az mount that was never designed to carry a front cell without a counterweight.
Its 4.6 star average across 947 ratings, with 76 percent at five stars, places it level with the 6 inch sheet on satisfaction. The sales rank is number 17 in Telescope Filters, slightly behind the 6 inch version.
What makes this size worth the extra material is yield. One 8 inch square produces a full front filter for an 8 inch tube and still leaves enough area for a finder filter and a piece for a smaller scope, so owners with several instruments tend to buy one sheet rather than three.
Model BP-8, manufacturer part number BP-8, 8 inch by 8 inch dimensions, polymer enclosure, no coating, and a set name of ultra light. Water resistance is listed as not water resistant, which is expected for a film product but worth remembering if you observe from a damp field.
The material is the same black polymer used across this manufacturer’s sheet range, described in the listing as the most common filtering material for observing sunspots and granulation. Expect the same warm orange solar disk as the smaller sheets.
How to get the most out of a large sheet
Plan the cut layout before you touch the blade, because a mistake in the middle of a large sheet wastes the piece you were saving. Lay out a full-aperture filter, a finder filter and a small refractor filter on the sheet first.
Store the offcuts flat between two sheets of clean paper. Black polymer is described in forum discussion as a good middle ground between fragile film and heavy glass, but it still marks easily and a scratch over the aperture is what you will be looking through for the rest of the session.
Who it does not suit
If your only instrument has a front aperture well under 8 inches, the 4 inch and 6 inch sheets cover the same job with less waste. And if you want the filter to arrive complete with hardware, this is the wrong format entirely; the pre-mounted Celestron filters are built for that.
Again, the maker’s instruction stands: use tape so the filter cannot fall while you observe.
4. Celestron EclipSmart 8 Inch Solar Filter – Premium Pick, Ready to Use
Celestron EclipSmart 8″ Solar Safe Eclipse Telescope Filter – ISO Compliant
Model 94244 for Celestron 8 inch Schmidt-Cassegrain and EdgeHD tubes, ISO 12312-2:2015(E) compliant
Pros
- Conforms to ISO 12312-2:2015(E) for direct solar viewing
- American Paper Optics film independently lab tested
- Two hook and loop straps hold it to the objective
- Backed by a two year US warranty
Cons
- Restricted to Celestron 8 inch SCT and EdgeHD tubes
- Costs more than any other filter in the set
- Finding and centring the Sun takes practice
If you own an 8 inch Celestron Schmidt-Cassegrain or EdgeHD, this is the best solar filter for telescopes in the roundup because the fit problem disappears. It is sized for your tube, it is certified, and it is held on by straps. There is nothing to build.
Nearly 600 ratings at 4.5 stars with 76 percent at five stars reflect exactly that kind of satisfaction. Buyers consistently mention the certification and the made-in-USA film as the deciding factors.
Two hook and loop straps secure the filter across the objective. That is enough to hold against normal handling, and it is far quicker to attach and remove than tape, which matters during a partial eclipse when you need to get the filter off and back on repeatedly.
The film is produced by American Paper Optics, a supplier recommended by NASA and the American Astronomical Society and independently tested by a third-party laboratory. Coated construction is listed as scratch resistant, the colour is a natural orange, and the dimensions are 9.25 inch by 9.25 inch at 4 ounces.
A two year limited warranty from Celestron covers manufacturing problems. For an eight inch aperture, that combination of certification, warranty and a secure strap mount is what separates this from a sheet of film.
Before you point it at the Sun
Confirm your telescope is actually an 8 inch SCT or EdgeHD. This filter does not stretch to 6 inch tubes, to refractors, or to other brands, and the listing also notes a 6 inch SCT variant exists as a separate item.
Centre the Sun at low magnification first. Owners report that locating a full-aperture solar disk through a filter is more forgiving than locating a small opening, but it still takes a few minutes the first time.
When to buy something else
If your Celestron is a 130mm reflector or a 70mm refractor, use the model-specific filters further down instead. If your instrument is not a Celestron, the universal fold-over filter or the Astromania metal cap will fit, and neither is restricted to one optical design.
Owners also mention handling the surface directly, which is the one avoidable mistake with a factory-made film filter. Treat the face as glass even though it is not.
5. Celestron EclipSmart Universal Filter – Best for Small Telescopes and Spotting Scopes
Celestron EclipSmart Universal Solar Filter for Telescopes
Model 44428, folding filter for objective lenses from 75mm to 100mm outside diameter
Pros
- Adjusts to fit 75mm to 100mm objective lenses
- Works across telescopes
- spotting scopes and DSLR cameras
- ISO 12312-2:2015(E) compliant American Paper Optics film
- Folds flat into the included reusable bag
Cons
- Paper construction is less durable than metal or rigid cells
- Fit range excludes larger and smaller tubes
- Effective aperture is smaller than the full objective
This is the filter for the person with a small refractor, a spotting scope and a camera body who wants one purchase instead of three. The adjustable side panels and elastic band fit objective lenses from 75mm to 100mm outside diameter, and the listed compatible devices run from PowerSeeker and Travel Scope through Astro Fi 90mm, Regal M2, Ultima, LandScout, TrailSeeker and the C70 Mini Mak.
Its 4.2 star average across 452 ratings, with 62 percent at five stars, is lower than the dedicated filters, and the reason is consistent across reviews: the effective aperture is smaller than the full objective, so the Sun is harder to find.
Box contents are one folding solar filter and rubber bands, and the whole thing folds flat into a reusable bag. For eclipse travel or a shared observing kit, that packability is worth more than a slightly larger aperture.
Model 44428, part number 44428, photo filter factor listed as 16 times, photo filter size 7.5 centimeters, screen size 7.5 centimeters, paper enclosure material and manual exposure control. The sales rank of number 7 in Telescope Filters shows how often people reach for it.
The film is the same American Paper Optics material specified by Celestron across this range, and it carries the same ISO 12312-2:2015(E) claim, with a two year limited warranty behind it.
Getting the most out of a folding filter
Measure the outside diameter of the tube before ordering and compare it against the 75mm to 100mm window, because this is not an adjustable-by-hope product. Tighter tubes will simply not reach the band.
Centre the Sun at the lowest power your setup offers, then increase magnification. With a smaller effective aperture, the trick of covering half the opening with a hand to reduce glare and find the disk works well, then move the hand away once it is centred.
Where the paper construction bites
Reviewers describe the paper body as feeling fragile compared with a metal cell, and it will not survive being folded tightly into a pocket repeatedly. If you are rough on equipment, the rigid aluminium option further down is the safer bet.
It is also the only filter here that suits a DSLR as well as a telescope, which is the single strongest reason to consider it for a mixed kit.
6. Thousand Oaks BP-12 12×12 Filter Sheet – Highest Rated, Flattest Surface
Thousand Oaks Optical BP-12 12 inchx12 inch Solar Filter Sheet for Telescopes, Binoculars and Cameras
Model BP-12, 12 inch by 12 inch black polymer sheet weighing 200 grams
Pros
- Highest rated in the set at 4.7 stars with 86 percent five star ratings
- Flat full opening surface without wrinkles or creases
- Enough area for a telescope
- finder
- binoculars and a pocket viewer
Cons
- Largest sheet and the most material in the set
- Cardboard packaging with no storage case
- An unprotected sight block must be removed or covered before observing
This sheet is the reason to look past sheet filters generally. At 4.7 stars across 437 ratings, with 86 percent of ratings at the full five stars, it has the highest average and the highest share of top marks of anything in this roundup.
The structural difference is the surface. The listing describes black polymer as giving a flat surface compared with other thin film filters that carry wrinkles and creases. Owners pick that up immediately in the eyepiece, because a flat sheet across a large aperture does not ripple the image the way a loose film square does.
At 12 inch by 12 inch and 200 grams, one sheet is a genuine workshop quantity. The stated uses include a camera, a telescope, a finder, binoculars and a pocket eclipse viewer, which is more finished filters from a single purchase than any other option here.
Model BP-12 with part number BP-1212, polymer enclosure material, orange solar image, made in the USA. The sales rank of number 39 reflects a smaller buyer base, but the rating distribution reflects how well those buyers like it.
Two practical notes from the listing itself. The sheet arrives in cardboard rather than a case, so store it flat between clean sheets of paper yourself, and remember to remove or cover an unprotected sight block on the telescope before observing, since that block is a second path for sunlight.
When the extra area actually pays off
Count your finished filters before you commit. If you have a 10 inch or 12 inch Dobsonian, a finder, a pair of binoculars and a spotting scope, this is the only sheet in the group large enough to cover them all at full aperture in one purchase.
Cut with a very sharp blade on a hard surface. A crease across a 12 inch square is harder to hide optically than a small one, because more of the aperture is affected, and the flatness that makes this sheet good is what a fold destroys.
Who should buy something smaller
If you own one small refractor, this is more sheet than you will use and the offcuts will be stored for years. The 4 inch sheet covers a single small instrument perfectly well and the 8 inch sheet is the better middle ground for a moderate collection.
Judged purely on consistency of owner satisfaction, though, this is the sheet I would pick first, and the flat full-opening surface is the reason.
7. Celestron EclipSmart Filter for 127mm and 130mm Reflectors
Celestron EclipSmart Telescope Solar Filter for 127mm & 130mm Reflectors
Model 94222, fits PowerSeeker 127EQ, Astro Fi 130, NexStar 130SLT, Omni XLT AZ 130 and SkyProdigy 130
Pros
- Covers a broad range of 127mm and 130mm Celestron reflectors
- Two hook and loop straps plus a safety cap
- ISO 12312-2:2015(E) compliant third party lab tested film
- 4.6 stars across 156 ratings
Cons
- Viewable area is only a small central circle
- Limited to specific Celestron reflector models
- Strap attachment is less rigid than a clamped cell
The 130mm tabletop reflector is one of the most common first telescopes sold, and this filter is built for that whole family. The listed compatible devices cover PowerSeeker 127EQ, Astro Fi 130, NexStar 130SLT, Omni XLT AZ 130, SkyProdigy 130, StarSense Explorer LT 127AZ and StarSense Explorer DX 130AZ.
Owners confirm the fit works, with 4.6 stars across 156 ratings and 77 percent at five stars. Eclipse photos and visual views in natural orange both come up often in that feedback.
Two hook and loop straps hold the filter to the objective, and unlike some competitors, a safety cap protects the outer surface when the filter is off. That cap matters more than it sounds, because the exposed film is the most fragile part of the whole assembly.
Model 94222, plastic enclosure, 7.25 inch by 7.13 inch dimensions at 3.04 ounces, photo and screen size of 15 centimeters. Available variants also cover PS127EQ, SSE DX 130, 130SLT, AM114EQ and 114AZ-SR.
The film is American Paper Optics material with the same ISO 12312-2:2015(E) compliance and two year US warranty that runs across the Celestron solar range.
The small opening, and how to work with it
The repeated complaint in reviews is the size of the clear centre. A small opening means the Sun is harder to locate, especially with a fast Newtonian and a wide field, so plan for the hunt rather than expecting instant acquisition.
Use your lowest magnification eyepiece first, cap half the view with your hand or a hat to dim the glare, and find the disk. Then centre it, remove the shade, and step up in magnification. Budget a few minutes per setup until you know the drill.
Alternatives for other setups
Owners of a Dobsonian or an 8 inch SCT should not force this one. It fits neither. The universal fold-over filter covers smaller tubes, the metal cell covers a different tube range, and the 8 inch sheet covers a large aperture with no compatibility question at all.
For a matched 130mm Celestron, though, this is a well-made filter that covers the model list you are likely to own.
8. Astromania Deluxe 100mm Metal Cap Filter – Neutral White Solar Image
Astromania Deluxe Filter 100mm Adjustable Metal Cap for Telescope Tubes with Outer Diameter from 70mm to 92mm Aperture 75mm
SKU_AM_DSF100, anodised aluminium cell with Baader Astro film, 75mm aperture inside 100mm outside
Pros
- Rigid anodised aluminium cell with three clamping screws
- Baader Astro film blocking 99.9 percent of incoming light
- Bright white light image rather than dull orange
- Meets ISO 12312-2:2015
Cons
- Clamping screws are described as overlong and awkward
- Will not go over tubes at the stated 92mm maximum
- Film is bare and unprotected in the ring and scratches easily
Every other filter in this roundup renders the Sun orange. This one renders it bright white, because it uses Baader Astro film in a solid anodised aluminium cell, and for observers who dislike the warm cast that is the entire reason to buy it.
The technical specification lists Baader Astro film blocking 99.9 percent of incoming light, an inside diameter of 75mm, an outer filter diameter of 100mm, and a fit range for optical tubes with an outside diameter from 70mm to 92mm. It meets ISO 12312-2:2015.
Three clamping screws with protective plastic caps pull the cell down over the tube. The caps keep the screw tips from marking your telescope, and the aluminium is a far more rigid platform for the film than cardboard, paper or a taped card frame.
Dimensions are 3.94 inch by 3.94 inch at 5.12 ounces, with aluminium and plastic materials and a listed photo filter factor of 1000 times. The cell is a fixed part, not something you cut yourself.
It is also the lowest rated item here, at 4.1 stars across 130 ratings with 62 percent at five stars. The complaints cluster around fit rather than the filter material.
Measure before you order, every time
Several buyers report that the cap will not go over a tube at the stated 92mm upper limit. The dominant piece of advice across those reviews is simply to measure the outside diameter of your optical tube first and compare it against the range before ordering.
Also budget time for the screws. Owners describe them as overlong and awkward, which is a minor irritation rather than a defect, but it is easier to accept once you know to expect it.
Handling the exposed film
The film sits bare in the aluminium ring with no protective glass, so it scratches easily. Treat the ring the way you would treat a camera sensor: keep it capped when it is off the tube, and inspect it before every session.
If you want the white solar image but do not want to deal with a small aperture, this cell is closer to full diameter than the Celestron fold-over filter. If you would rather have zero assembly and a certified film in a matched cell, the 8 inch Celestron remains the simpler path for 8 inch tubes.
9. Rainbow Symphony 101mm Black Polymer Filter – Pre-Sized, No Cutting
Rainbow Symphony Solar Filter 101mm Black Polymer
Model 10713, pre-sized 101mm black polymer filter in multi-coated construction
Pros
- Arrives ready to use with no cutting or taping
- Black polymer resists creasing better than bare film
- Sizes also made in 50mm
- 60mm
- 70mm and 76mm
- Suitable for camera bodies and telephoto lenses
Cons
- Compatibility is documented for cameras rather than telescope tubes
- Smallest review count of the well reviewed options at 115 ratings
- Ranked number 84 in Telescope Filters
This is the compromise pick for someone who wants the durability of black polymer without the work of cutting a sheet. It is made at 101mm, ready to place over a matching tube, and it needs no tape, no tools and no holder construction.
Ratings sit at 4.2 stars across 115 reviews with 65 percent at five stars, and 9 percent at one star. That is the smallest review base of the better-regarded items here, and it carries the weakest demand signal at number 84 in Telescope Filters.
Dimensions are 3.98 inch by 3.98 inch with a photo filter size and screen size of 10.1 centimeters. Construction is listed as multi-coated black polymer, and the material is described as a durable, crease-resistant alternative to bare Mylar film.
The other diameters matter more than they first appear. The same filter is made in 50mm, 60mm, 70mm and 76mm, so if your collection includes a small refractor and a larger spotting scope you can match sizes rather than trimming one sheet to fit everything.
One caveat to check before buying: the listed compatible device is cameras. Documentation focuses on camera bodies and telephoto lenses more than telescope tubes, so confirm your tube diameter against the 101mm size yourself rather than relying on the listing.
Is black polymer the right material for you
Forum discussion on Cloudy Nights treats black polymer as the sensible middle ground: more durable than thin aluminized film, less heavy and less expensive than metal-on-glass. That is exactly the trade this filter makes, and it is why the colour is described as closer to neutral than the strong orange of other films.
The multi-coated construction in the listing is rated for ultraviolet filtering, which is how a pre-sized polymer disc keeps the solar image at a comfortable brightness without a second cut layer.
When a sheet is the better answer
If your tube is an unusual diameter or your kit includes items well above 101mm, the sheets in this roundup cover more aperture per purchase and cost less per usable filter. Choose this one when convenience and material quality both matter more than covering many sizes at once.
Its low review count is worth weighing, simply because a smaller base of owners means fewer reports on long-term durability.
10. Celestron EclipSmart Filter for AstroMaster 70 Refractors
Celestron EclipSmart Solar Filter for AstroMaster 70 Refractor Telescopes
Model 94246, fits AstroMaster 70AZ, AstroMaster LT 70AZ and AstroMaster 70EQ refractors
Pros
- ISO 12312-2:2015(E) compliant American Paper Optics film
- Three safety screws plus a safety cap
- Fits the very common AstroMaster 70 family directly
- Two year warranty
Cons
- Supplied plastic thumbscrews break and some fall short of the objective
- Small central viewing opening
- Film is fragile and only fits 70-series and Travel Scope 60 tubes
The AstroMaster 70 is everywhere. It is the starter refractor sold in electronics shops and given away as a bundle, so a model-specific filter for it is genuinely useful rather than a niche accessory.
With 52 ratings at 4.2 stars, this is the least-reviewed filter in the roundup, and it carries a correspondingly thin base of owner reports. Most owners confirm it fits their AstroMaster 70AZ and produces usable views and eclipse photographs.
Three safety screws hold the filter to the objective and a safety cap protects the surface when it is not in use. Model 94246, part number 94246, proprietary Mylar enclosure, 2.76 inch by 2.76 inch dimensions, and a listed photo filter size of 7 centimeters against a 10.2 centimeter screen size.
Box contents are the filter body, three safety screws and an instruction sheet. The film is the same American Paper Optics material used across the Celestron range, with the same ISO 12312-2:2015(E) compliance and a two year warranty.
The listed variants cover the TS60 and TS60DX alongside the AM70 and 70LT, so a Travel Scope 60 owner should confirm which variant they need rather than assuming this one fits.
Hardware is the issue, not the film
Reviews concentrate on two things. The supplied plastic thumbscrews break easily and some are too short to reach the objective on wider tubes, and the viewable area is a small central circle that makes finding the Sun difficult at first.
Work around the screws rather than forcing them. Check that each one threads fully before tightening, and if a screw will not reach, stop and confirm the tube model before continuing.
Alternatives for a 70mm refractor
The universal fold-over filter covers 75mm to 100mm objectives, which includes many 70mm AstroMaster tubes, and it does not care about the model number at all. The 4 inch or 6 inch sheet also covers a 70mm front with room for a taped border.
Buy this one if you want a factory-matched cell with screws and a cap and your tube is confirmed as an AM70 or LT 70AZ. If your telescope is something else in the 70mm range, the universal filter is the safer purchase.
How to Choose a Solar Filter for Your Telescope
Measure the outside diameter of the tube, not the aperture
This is the question that comes up most often on r/telescopes, and the answer is consistent: measure the outer diameter of the optical tube, then compare it against the filter size. Aperture and outside diameter are different numbers on most telescopes, and a filter matched to the aperture will often be too small to hold a proper taped border.
For a homemade cell, add roughly 10mm per side for the tape. For a slip-on or clamping filter, compare the fit range against the outside diameter, and where a listing states an upper limit, stay a few millimeters below it.
Sheet, fold-over, or rigid cell
Sheets give the most flexibility per purchase and the least in convenience. One sheet can serve a telescope, a finder, binoculars and a camera, but you supply the holder and the attachment, and that holder has to be secure.
Fold-over filters sit between the two. They arrive finished, adapt to a range of tube diameters, and pack flat, at the cost of a smaller effective aperture and a lighter-duty body.
Rigid cells are the most secure and usually give the largest viewing opening, and they are tied to specific tube sizes. If you never want to touch a blade or a roll of tape, this is the format to buy even though you have fewer size options.
Film, black polymer, or metal on glass
Aluminized polyester film gives the highest resolution and sharpest granulation and tears most easily. Black polymer sits in the middle, with a flat surface and better crease resistance, and metal on glass is the most durable and heaviest option.
None of the ten products here is metal on glass, and none is a hydrogen-alpha filter. If prominences and the chromosphere are what you are after, you need an H-alpha system such as a DayStar QUARK or a dedicated Coronado or Lunt telescope, which is a different category of purchase rather than a different brand of white-light filter.
Colour is a preference, not a quality measure. Orange is normal for polymer and aluminized film; the Astromania cell is the one here that gives you a neutral white disk.
Can a plain neutral density filter work for solar viewing?
No. The neutral density filters sold for camera lenses reduce visible light by a stated number of stops, and a small 16x factor is nowhere near what a telescope needs. The 99.9 percent blocking quoted for cell-mounted products in this roundup is the level to compare against, and anything intended only as an exposure aid should never be placed in a visual observing path.
Run a safety routine every time
Before each session, confirm the filter covers the entire front aperture with no gap, inspect the surface for pinholes, creases and scratches, and confirm the attachment is firm before you swing the tube toward the Sun.
Remove any sight block cover only once the filter is in place, and never remove the front filter while the instrument is pointed anywhere near the Sun. During the partial phases of an eclipse, treat every moment before totality exactly as you would treat ordinary daytime observing.
The same sizing and fit logic we apply elsewhere shows up in our guides to pool filters for saltwater setups and cartridge filters for inground pools, where matching the part to the actual equipment matters just as much as the headline specification.
Frequently Asked Questions
What filter do you need to look at the sun with a telescope?
You need a solar filter that mounts over the front aperture of the instrument and conforms to ISO 12312-2, the international standard for filters used for direct solar viewing. Never attach the filter at the eyepiece, because concentrated sunlight reaches the eye before any rear filter can stop it. If the listed fit range does not clearly cover your tube, buy a different filter rather than adapting one.
Can I make my own solar filter for my telescope?
Yes, using a sheet of black polymer or aluminized film, and it covers a telescope, a finder, binoculars and a camera with one purchase. Cut the sheet larger than the outer diameter of the tube, allow a margin for tape on every side, cut on a hard surface with a sharp blade, and attach with several tape strips so it cannot lift. Inspect the film for pinholes and creases before every session, and never use a filter you have damaged or cannot clearly see through.
How do I choose the right size solar filter for my telescope?
Measure the outside diameter of the optical tube rather than the stated aperture, then compare it with the filter size. For a homemade filter from a sheet, add roughly 10mm on each side so the tape has a border. For a slip-on or clamping cell, check the stated fit range against your measurement and stay a few millimeters below the upper limit, because several owners report caps that will not go over a tube at the advertised maximum.
What is the difference between white light and H-alpha solar filters?
A white-light filter reduces the whole visible spectrum evenly, so you see the photosphere in white or orange, with sunspots and granulation across the disc. A hydrogen-alpha filter passes only a narrow band of red light, which isolates the chromosphere and reveals prominences, flares and the solar limb in monochrome against a dark background. Every filter reviewed in this roundup is a white-light filter; H-alpha requires a dedicated system such as a DayStar QUARK or a Coronado or Lunt solar telescope.
Why are eyepiece solar filters dangerous?
A telescope concentrates sunlight onto the eyepiece. If you fit the filter at the back of the instrument and the filter is not already in place, the Sun is delivered straight to the eye at high intensity and can cause permanent damage almost instantly. A front-mounted filter stops the sunlight before it ever enters the optical path, which is why every safe solar observing guideline insists the filter goes on the objective and stays there.
Final Recommendations for Solar Filters in 2026
The best solar filters for telescopes in this roundup come down to which format suits how you actually observe. If you own one small instrument and a few extras, start with the Thousand Oaks BP-4 sheet, the most reviewed option here, and cut it to fit whatever needs covering. If your aperture is larger and you would rather have something finished and certified, the Celestron EclipSmart 8 inch filter is the strongest ready-made choice in the group.
For a mid-size reflector, a 130mm Celestron tabletop scope, or any mixed kit on a modest budget, the BP-6X6 sheet covers the most ground per purchase. The 12 inch sheet is the one to buy when you want several finished filters and care most about a flat, wrinkle-free surface, and the Astromania metal cap is the choice when the neutral white solar image matters more to you than the orange cast.
Whichever route you take, keep the filter on the front of the tube, check the surface every time you set up, and treat the partial phases of an eclipse exactly like any other daylight session.