Baader AstroSolar ASTF ClearWhite OD 5.1 140mm Solar Filter for Telescopes
When will I receive it?
Products marked In stock are dispatched promptly — the exact delivery estimate for your address is shown at checkout, before you confirm the order.
For international shipments, delivery times depend on the destination and are always displayed at checkout before payment.
Products marked Available on order require 5–15 business days for processing. Our team will keep you updated promptly if anything changes.
What are the warranty terms?
Shop with confidence: all our products include a 24-month legal warranty for conformity defects, managed directly by our team.
Many brands also offer extended warranty coverage beyond 24 months — contact us to find out the specific terms for the product you're interested in.
Click here for more information.
Can I return a product?
Yes: you have 14 days from delivery to return any product and receive a full refund — see our Refund Policy for full details.
Items must be returned in their original condition and packaging. Return shipping costs are the customer's responsibility.
Not sure which product is right for you? Contact us before buying — we'll help you find the perfect instrument so you won't need to return anything.
Sei un'azienda? Compila il modulo per la fatturazione
Clicca sul pulsante qui sotto per inserire i tuoi dati aziendali:
Vai al moduloThe Baader ASTF ClearWhite OD 5.1 Solar Filter for telescopes, aperture 140mm, belongs to the ASTF series (AstroSolar Telescope Filter), designed for medium to large high-end telescopes: a very good telescope deserves a very good filter!
AstroSolar ClearWhite OD 5.1 Film
The filter uses the Baader AstroSolar® ClearWhite Safety Film OD 5.1, metallized on both sides, designed for direct observation of the Sun and for building front-mounted filters for telescopes, binoculars, spotting scopes and telephoto lenses.
With an optical density of OD 5.1, the film reduces the intensity of sunlight by approximately 99.9992% (attenuation factor of approximately 125,000), compliant with the transmittance requirements of the EN ISO 12312-2:2015 standard for filters intended for direct observation of the Sun. Compared to the previous OD 5.0 version, the ClearWhite offers an even whiter, more neutral image of the Sun with a slightly higher optical density: sunspots, granulation and fine details of the photosphere appear sharp and high-contrast.
The film, free of streaks and bubbles, achieves at a thickness of just 0.012mm an optical quality comparable to that of the best plane-parallel glass filters. The double-sided coating ensures a particularly uniform filtering action.
Temperature-compensated cell
The film is mounted stress-free in a temperature-compensated cell, which maintains optical quality unchanged across different usage temperatures, without generating astigmatism during winter observations or with summer temperature changes. The aluminum mount has a white front ring that reflects heat, with raised edges that protect the film from contact with sharp metal surfaces.
Included: two sets of centering bolts (10mm and 20mm diameter, 38mm length) to fit the diameter of your optical tube or dew shield, three safety straps with adhesive pads and three rubber plugs to cover unused holes, plus mounting instructions.
Technical specifications
| Parameter | Value |
|---|---|
| Series | ASTF (AstroSolar Telescope Filter) |
| Film | AstroSolar® ClearWhite Safety Film OD 5.1 |
| Usable aperture | 140 mm |
| Attenuation | ~99.9992% (factor ~125,000) |
| Standard | EN ISO 12312-2:2015 |
| Mount | Aluminum, temperature-compensated cell |
| Brand | Baader Planetarium |
Who it's for
Ideal for amateur astronomers and astrophotographers who own a high-end telescope and are looking for the highest optical quality for visual observation and photography of the Sun in white light, both for daily monitoring of sunspots and for the partial phases of solar eclipses.