iOptron 70mm Adjustable Solar Filter
- 70mm Clear Aperture
- Fits Telescope Tubes with 86mm to 106mm Outside Diameters
- SolarLite Film with Optical Density 5 Rating
- Blocks All but 1/1,000th of 1% of Incoming Sunlight
- Durable Machined Aluminum Frame
This 70mm Adjustable Solar Filter turns your daytime telescope into a safe solar observatory, using SolarLite film that transmits only 1/1,000th of 1% of the Sun's light. Its machined aluminum cell provides a secure, adjustable fit for telescope tubes with an outside diameter from 86mm to 106mm. The filter's Optical Density 5 rating ensures protection for both your eyes and equipment, allowing you to observe sunspots, granulation, and transits with sharp, natural-color views.
The core of this filter is its SolarLite solar film, a specialized polymer engineered for direct solar observation. With an Optical Density (OD) rating of 5, it blocks 99.999% of the Sun's intense light, including harmful ultraviolet and infrared radiation, allowing only a safe 1/1,000th of 1% to pass through. Unlike some glass filters that can produce a colored tint, this film renders the Sun in a neutral, whitish-yellow hue, delivering high-contrast views of sunspots and surface granulation.
A solar filter is only safe if it stays securely attached to your telescope. This model features a durable, machined aluminum frame with an adjustable inner diameter to accommodate a range of instruments. It provides a firm, reliable grip on any optical tube with an outside diameter between 86mm and 106mm, making it a versatile choice for many popular 70mm to 90mm refractors. The lightweight yet rigid construction ensures it won't strain your focuser or affect your telescope's balance.
This filter is designed to fit any telescope, finder scope, or binocular with an outer tube diameter between 86mm and 106mm. Always measure the outside diameter of the front of your telescope tube, not the lens aperture, to ensure a correct and safe fit.
Yes, absolutely. The filter uses SolarLite film with an Optical Density 5 rating, which is the international safety standard for direct solar observation. It blocks 99.999% of sunlight, including all harmful IR and UV radiation. Always ensure the filter is securely mounted and has no scratches or pinholes before every use.
On an 80mm refractor, this 70mm solar filter will provide excellent views of sunspot groups. You will clearly see the darker central umbra and the lighter, surrounding penumbra of larger spots. The SolarLite film provides a high-contrast, neutral-colored image, making it easy to track the daily changes and movements of sunspots across the solar disk.
SolarLite film and glass filters are both safe when rated to OD 5, but they offer different viewing experiences and have practical trade-offs.
No. This is a white-light filter, designed for viewing the Sun's surface (photosphere), which includes sunspots and granulation. Solar flares and prominences are features of the Sun's chromosphere and are only visible with specialized, narrow-band hydrogen-alpha (H-alpha) filters and telescopes, which isolate a specific wavelength of red light.
The film is very delicate and should only be cleaned if absolutely necessary. Never use harsh chemicals or abrasive cloths. If you must clean it, use a gentle puff of air from a bulb blower to remove loose dust. For fingerprints or stubborn spots, you can lightly dab the area with a soft, lint-free tissue or cotton ball moistened with a gentle cleaning solution like diluted isopropyl alcohol. Do not rub or apply pressure.
| Clear Aperture | 70mm |
| Filter Material | SolarLite solar film |
| Film Transmission | 1/1,000th of 1% |
| Optical Density | 5 |
| Frame Material | Machined aluminum |
| Fit Range (OTA Outer Diameter) | 86mm to 106mm |
| Filter Outer Diameter | 112mm |
70mm Adjustable Solar Filter
× 1