What does ND 0.9 mean for the Explore Scientific Neutral Density Filter?

An optical density of 0.9 means the filter transmits only 12.5% of the light that passes through it. This is equivalent to a 3-stop reduction in brightness, making it ideal for viewing extremely bright objects like the Moon.

When should I use the Explore Scientific ND 0.9 filter instead of a variable polarizing filter?

Choose the fixed ND 0.9 filter when true color neutrality is critical. While a variable polarizer offers adjustable brightness, it can introduce a slight color cast and polarization artifacts. The Explore Scientific ND 0.9 provides uniform light reduction across the entire visual spectrum for the most natural view possible.

Is the Explore Scientific ND 0.9 filter too dim for observing Jupiter with an 8" SCT?

Yes, for most observers, this filter is too strong for planetary viewing. Reducing the light to 12.5% is excellent for the Moon's intense glare but will likely make details in Jupiter's cloud bands too dim to see clearly. A lighter filter, such as an ND 0.3 (50% transmission), is a better choice for planets.

Why use a 2-inch ND 0.9 filter?

The 2-inch barrel format allows the filter to be threaded directly onto 2-inch eyepieces and accessories. This is essential for observers using larger telescopes and wide-field 2-inch eyepieces, as it allows them to reduce brightness without causing vignetting or restricting the field of view.

How does the Explore Scientific ND 0.9 filter help split a double star like Sirius (Alpha Canis Majoris)?

The primary star, Sirius A, is so bright that its glare completely overwhelms its faint companion, Sirius B (the 'Pup'). The ND 0.9 filter dims the entire system by 87.5%, which reduces the overpowering glare from Sirius A enough for the faint pinpoint of Sirius B to become visible right beside it.

Will this Explore Scientific ND 0.9 filter change the color of the Moon?

No. This is a 'neutral' density filter, meaning it is engineered to reduce brightness uniformly across the entire visible spectrum. The Moon will appear significantly dimmer but will retain its natural grey, white, and tan colors without any added color cast.

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Explore Scientific Filtre à Densité Neutre ND 0.9 - 2"

par Explore Scientific

UGC ES-310240

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$59.99 USD - $59.99 USD

$59.99 USD

$59.99 USD - $59.99 USD

$59.99 USD

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Explore Scientific Filtre à densité neutre ND 0,9 - 2"

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Explore Scientific Filtre à Densité Neutre ND 0.9 - 2"