Top Rated Gear

Baader Planetarium 120mm AstroSolar Telescope Filter

SKU: AA2459312 MFR: ASTF-120
$109.00
Earn VIP Reward Points

Key Features

  • Enjoy safe solar viewing with this 120mm AstroSolar telescope filter, perfect for telescopes.
  • Achieve high contrast views of sunspots & solar details using this telescope filter.
  • This Baader Planetarium filter offers exceptional blocking performance for safe solar observation.
  • Threaded compatibility ensures a secure fit; outer diameter is 210mm for stability.
  • Durable construction guarantees long-lasting use for all your solar viewing adventures.
  • Observe the sun in white light with integral light filtration, enhancing your solar viewing.
See More Product Details
Special Order?Estimated to Ship: 08/16/2025
Free Shipping

See Options

1

Protect your gear with Adorama Protect.* Learn more

1 Year

$11.99

2 Year

$21.99

3 Year

$29.99

Available to U.S. customers only.

Need help? Ask our experts.

Overview
Compare
Specs
Protection
Q&A

Questions & Answers

Reviews about this item

Review Summary

2021-05-24T13:13:40

Rated 5 out of 5

Great item for both visual and photography of the sun through your telescope.

Very well made product that fits my Celestron 7" Maksutov perfectly.

ROBERT F.

2018-09-28T16:37:58

Rated 5 out of 5

Good quality filter

it fit my celestron 127slt like a glove. the sun is white in this filter and it is neet to look at the sun spots and solar flares. I wanted something quality so I didn’t hurt my eyes and this did the trick .

brady s.

2018-09-20T13:50:36

Rated 5 out of 5

Easy, inexpensive solar filer

Easy to use and very inexpensive, works fine.

GARY S.

2017-09-01T07:25:06

Rated 5 out of 5

Bought for the 2017 Total Eclipse!!!!!!!

I purchased this filter after reading many reviews. I used it for the Total Solar Eclipse a couple weeks ago. It was awesome. The filter provided great visual images. I didn't try any photography with it this time fort I'm still trying to figure that part out. I used the filter with my Celestron EVO 9.25 and am totally pleased with the performance of the filter. I would definitely recommend this filter to everyone interested in doing some solar viewing.

Wesley P.

2017-09-01T06:29:48

Rated 4 out of 5

Works great, but beware the size and Velcro

I got this filter to attach to my telescope for the 2017 solar eclipse. Optically it performed great and everyone had a good time looking at the sun slowly disappear, at the sunspots, and at the chromosphere for a few short seconds. In addition to being good optically, the filter itself seems to be well made. Where things falls flat though is the mount. Other reviewers have stated that correct sizing is critical so before getting this I measured the tube diameter of my scope under the assumption that this was the necessary measurement. Apparently it is not. A 150mm filter is grossly oversized for a 149mm tube. The 150mm appears to refer to the size of the aperture though which the filter transmits light, while the mounting system is several centimeters larger in diameter. Baader Planetarium does have sizing guide, but it is hard to find. Additionally, the mounting system uses glue-backed Velcro pads that you stick onto your telescope for safety. The idea is nice but the execution here also falls flat. The glue is not particularly well adhered to the Velcro pad and tends to pull off before the Velcro separates. Also, some might not like the idea of having Velcro pads glued onto their scopes, binoculars, or (especially!) telephoto lenses.

JASON G.

2017-08-11T17:32:33

Rated 5 out of 5

Works great on Sigma 120-300mm zoom lens

This was a last minute purchase and I was not sure if it would even fit. Thankfully it fit onto the lens hood of the lens.

DON C.

2017-05-30T10:13:00

Rated 5 out of 5

Solar Filter for Nikkor 200-500 mm Zoom lens

The filter assembly is well made and high quality. It fits the lens perfectly, but just. The only way to attach this particular filter is to install it on the lens hood. It has three rubberized posts that are slightly adjustable to accommodate different dimensions, but the range of adjustment is quite small (approximately 3mm per post). I set my posts set as far inward as possible and in this position it is possible to insert them carefully into the lens hood and force them down until the rim of the filter frame is against the lens hood. There are also three Velcro straps to secure the filter from accidentally coming off. I have taken several sets of trial images and have not noticed any light leakage or occlusion of the sun's disc. I would recommend that anyone considering this filter check the specs carefully to get the correct size for proper fitment. This particular filter would not attach properly to a tulip style lens hood.

Michael E.

Select a plan in the Add Protection section above and purchase with this product by clicking “Add to Cart”.

image-protection

TRUSTED PROTECTION PLANS, EXCEPTIONAL SERVICE.

Invest In Your Gear and Peace Of Mind!

Accidents happen. Protect your favorite Adorama products and purchase a protection plan to stay covered from accidental damage, mechanical or electrical failures, and more.

Repair or Replacement

Repair or Replacement

If we can’t fix it, we’ll replace it at no additional cost.

Accidental Damage

Accidental Damage

Protect your product from drops, spills, and more.

Peace of Mind

Peace of Mind

Enjoy your gear without fear. We have you covered!

Failure Protection

Failure Protection

When regular use of your product over time results in mechanical or electrical failure.

Zero Deductible

Zero Deductible

We will never charge you a deductible after the purchase of a plan.

Customer-Focused Support

Customer-Focused Support

Our claims process is simple & easy and our customer service team is happy to help.

Adorama Protect powered by Extend is available for purchase to customers in the United States. Not available for international or U.S. territories purchases. Plans on open box items do not cover pre-existing damage.
Adorama Protect plans are available for ABS clients. If you have any questions or require assistanse, please call 800-223-2500

Baader Planetarium ilter Specifications

  • Usage

    Visual solar observation and imaging at high magnification

  • Astrosolar Film

    AstroSolar Safety Film

  • Optical Density

    5

  • Inner Diameter / Clear Aperture

    120mm

  • Outer Diameter

    210mm

  • Filter Mounted

    Yes

  • Outer Clampingrange (10mm Bolts)

    150 - 180

  • Inner Clampingrange (10mm Bolts)

    170 - 200

  • Outer Clampingrange (20mm Bolts)

    140 - 170

  • Inner Clampingrange (20mm Bolts)

    180 - 210

  • Solar Wavelength

    Whitelight (integral light)

  • Weight

    0.68kg (1.5lbs)

  • UPC Code

    4047825033017

About Baader Planetarium ilter

FEATURED REVIEWS

Solar Filter for Nikkor 200-500 mm Zoom lens

By Michael E.

The filter assembly is well made and high quality. It fits the lens perfectly, but just. The only way to attach this particular filter is to install it on the lens hood. It has three rubberized posts that are slightly adjustable to accommodate different dimensions, but the range of adjustment is quite small (approximately 3mm per post). I set my posts set as far inward as possible and in this position it is possible to insert them carefully into the lens hood and force them down until the rim...

View full Review

Great item for both visual and photography of the sun through your telescope.

By ROBERT F.

Very well made product that fits my Celestron 7" Maksutov perfectly.

Where precision and safety in solar observation are paramount, the Baader 120mm AstroSolar Telescope Filter emerges as the pinnacle of solar filtration technology. This high-quality filter is meticulously crafted with Baader's AstroSolar Safety Film OD 5.0, ensuring that the true optical quality of the diffraction-limited film is preserved for the most discerning astronomers and astrophotographers.

The innovative design of the Baader Solar Filters offers a professional and secure method to observe and image the Sun, free from the common pitfalls of ready-made filters that often compromise image quality by stretching the material. Unlike these inferior products, the AstroSolar film in this filter is mounted entirely stress-free, maintaining its high precision plane optical window characteristics. This results in an efficient and advanced viewing experience, where slight ripples in the film are not a defect but a feature indicating optimal performance.

The filter boasts a clear white IR-rejecting front ring with reinforcing raised edges, designed to protect the delicate solar filter material from any contact with sharp metal edges. The durable construction includes non-rotating sliding fasteners made from aluminum, which are equipped with machined indicators for easy adjustment. The centering bolts, designed to fit a wide variety of mechanical tube diameters, can be adjusted without tools and secured firmly with integrated Phillips screws if desired.

An index scale beside each adjustment slot ensures fast and repeatable mounting of the filter cell onto different telescope tubes. Black sliding washers are included to cover the full length of the adjustment slots in the aluminum frame, blocking any stray sunlight from passing through the filter cell beside the filter area.

For added security, the filter comes with three safety straps that secure the position of the filter cell with Velcro-adhesive pads, ensuring a secure fit in front of the telescope under all circumstances, including gusts of wind. The front side of each filter cell features a printed warning text, urging users to read the instructions before use.

The ASTF (AstroSolar Telescope Filter) Baader Solar Filter is designed to withstand temperature changes without putting stress on the film, thanks to its temperature compensated cell. The film is cemented onto an injection molded ring that matches the thermal expansion of the AstroSolar filter material, ensuring consistent optical quality from -30°C to +50°C.

Safe for solar observation and photography with all high-end telescopes and extreme tele-lenses, this filter is suitable for the highest magnifications and detailed observation of individual sunspots. Each ASTF Filter includes two sets of centering bolts (38mm length, 10mm and 20mm diameter), three safety straps with glue-pads, three rubber plugs to cover unused holes, and mounting instructions, all packaged in a protective cardboard gift box fit for safe shipping. With the Baader 120mm AstroSolar Telescope Filter, you can confidently capture the sun's grandeur with impeccable clarity and safety.

Baader Planetarium ilter Features

  • High-quality Baader AstroSolar Safety Film OD 5.0 for premium solar observation
  • Innovative stress-free mounting ensures consistent, high-precision optical quality
  • Durable IR-rejecting front ring with reinforced edges to protect filter material
  • Advanced temperature compensated cell design for use in extreme climates
  • Efficient no-tool adjustment with secure fastening for a variety of telescope tubes
  • Includes three safety straps and adjustment index scale for reliable, repeatable setup

Warranty Information

This product has a limited warranty of 24 months for parts and 24 months for labor.

Key Features

  • Enjoy safe solar viewing with this 120mm AstroSolar telescope filter, perfect for telescopes.
  • Achieve high contrast views of sunspots & solar details using this telescope filter.
  • This Baader Planetarium filter offers exceptional blocking performance for safe solar observation.
  • Threaded compatibility ensures a secure fit; outer diameter is 210mm for stability.
  • Durable construction guarantees long-lasting use for all your solar viewing adventures.
  • Observe the sun in white light with integral light filtration, enhancing your solar viewing.

What's in the box:

  • aader Planetarium 120mm AstroSolar Telescope Filter
  • 3x 10x38mm Centering Bolts
  • 3x 20x38mm Centering Bolts
  • 3x Safety Straps with Glue-pads
  • 3x Rubber Plugs
  • Instruction Manual
  • Baader Planetarium Warranty F