Pellucid Selene lunar filter 2 in, premium grade

Specifications

Description

The Selene lunar filter is a neutral density filter in a 2 in threaded cell, designed to reduce the brightness of the Moon at the eyepiece. It transmits about 12 percent of incident light across the visible spectrum, so surface detail stays visible while glare falls substantially. Because the filter has no passband, it does not isolate any emission line, and it does not shift the color of the image in a noticeable way.

Near full phase, the lunar surface is bright enough to cause discomfort and loss of contrast at high magnification, and the bright limb can overwhelm the eye. Lowering the light level lets you see terminator shadows and crater floors with less dazzle, and it helps you keep your dark adaptation when you switch to fainter targets afterward. The filter also helps with bright planets such as Venus and Jupiter, whose images can wash out at high power.

The filter threads into the front of any 2 in eyepiece or the nosepiece of a 2 in diagonal, and it can be mounted on a 2 in filter adapter for other accessories. Use it for lunar and planetary observation only. A neutral density filter does not reduce sunlight to a safe level, so never use this filter to view the Sun through a telescope or binoculars, because the risk of permanent eye injury remains. Store the filter in its case when not in use to protect the glass from dust and scratches.

The glass is ground to a uniform thickness and coated on both surfaces with an anti-reflection layer, which limits internal reflections and ghosting. The transmission is consistent across the field, so the view remains even at the edges of the eyepiece. Clean the glass with a soft brush and a lens cloth, and avoid touching the optical surfaces with bare fingers.

About this configuration

All configurations of the Pellucid Selene lunar filter 2 in share the same filter glass design; the options change the grade, the coating, and the case. The premium grade uses polished glass with tighter flatness tolerances, which helps at high magnification. Premium grade filters are checked for the position of the passband before they leave the factory. Hard-sputtered layers keep their passband stable over time, which matters if you compare images taken years apart.

A padded pouch is easy to open with cold fingers, which helps when you swap filters during a session. The 2023 edition uses the same coating design as later years, with small differences in the cell markings. A filter does not make objects brighter; it darkens the sky background more than the target, which raises contrast.

What's in the box

• Lunar neutral density filter in 2 in threaded cell
• Padded storage case
• Padded pouch

Compatibility notes

• Threads into 2 in eyepieces, diagonals, and filter adapters (M48 x 0.75).
• Usable with any telescope that accepts 2 in accessories.