Pellucid Selene lunar filter 2 in

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 standard grade uses the same coating design as the higher grades, with wider tolerances on flatness. Standard grade glass suits visual observing at low and medium magnification. The hard-sputtered coating resists scratches and humidity, so the filter tolerates cleaning better over the years.

An aluminum case with a foam insert keeps the filter safe during travel to a dark site. This is the 2024 edition, which revised the cell knurling and the case insert of the Selene line. Check the size in the specifications against your eyepiece barrels, star diagonal, or filter wheel before you choose.

What's in the box

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

Compatibility notes

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