Safely observe the sun with your own telescope
The sun is the most dynamic object in the sky: sunspots appear and disappear, and during a solar eclipse, you naturally want to be in the front row. However, looking at the sun without a proper filter is life-threatening for your eyes and your telescope. The Omegon Helievo solar filter solves that. The built-in ND 5.0 solar film weakens sunlight 100,000 times, leaving only a safe, high-contrast white-light image.
You can attach the filter in seconds: slide it onto the front of your telescope and tighten the three aluminum set screws with plastic tips. They clamp firmly without scratching your tube. The film is housed in an anodized aluminum mount and can be unscrewed and replaced later.
What size should I choose? (explained very simply)
Important to know: the size of the filter does not refer to the aperture of your telescope, but to the outer diameter of the pipe (or the dew shield of a lens telescope, which is the projecting rim at the front). So, take a measuring tape or ruler and measure the outside of the tube at the front. If your measurement falls within the range of a variant, then that variant will fit.
As a rule of thumb, the tube is always a bit wider than the lens opening. This table will help you get started:
| Your telescope (aperture) | Examples | Choose this variant |
|---|---|---|
| Finderscope or mini-refractor (40–50 mm) | 8x50 Binoculars, Travel Binoculars | 44–68 mm |
| Small refractor telescope (60–70 mm) | 70/700 refractor | 64–88 mm |
| 80–90 mm or 90 mm Maksutov telescope | 80/400, 90/900, Mak 90 | 84–108 mm |
| Refracting telescope 100-102 mm or Newtonian 114 mm | 102/660, 114/900 | 104–128 mm |
| Newton 130 mm refractor 120 mm | 130/650, 120/600 | 124–148 mm |
| Maksutov 127mm and comparable | Mak 127 | 138-153 mm |
| Newtonian refractor around 150 mm (narrow tube) | 150/750 with pipe up to 168 mm | 144–168 mm |
| Newton 150 mm with wider tube | 150/750 with pipe up to 188 mm | 164–188 mm |
| Large refractors and Newtonians | Tubes from 173–193 mm | 173-193 mm |
| Large instruments up to 208 mm tube | 180 mm Maksutov ed. | 184–208 mm |
Are you hesitating between two sizes? Be sure to measure it afterward! The table is just a guideline, since pipe diameters vary by merk. If your measured size falls in the middle of a range, the filter will fit most securely.
What can you see with it?
With the Helievo filter, you can see the sun in white light: dark sunspots with their gray edges (penumbra), the granular structure of the sun's surface (granulation), and of course, every phase of a partial or total solar eclipse. Photographing through the filter is also safe, using your smartphone on the eyepiece or with a camera.
Kenmerken at a Glance
- 100% Safe Solar Viewing: ND 5.0 film, transmission 1/100,000
- High-quality solar film for a sharp, high-contrast image
- Clamped with 3 set screws, plastic tips protect your tube from scratches
- Sturdy, anodized aluminum housing
- Foil later replaceable (housing unscrewable)
- Available in 10 sizes: for pipes from 44 to 208 mm outside diameter
Warning: Never look at the sun without a mounted solar filter, not even briefly. Check the film for damage before each use and always cover or remove the viewfinder.
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