Alpine Astronomical Baader Dark Blue Colored Bandpass Eyepiece Filter (1.25")

BH #ALFCFDB1 • MFR #FCFDB-1
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Alpine Astronomical Baader Dark Blue Colored Bandpass Eyepiece Filter (1.25")
Key Features
  • Planetary Viewing/Imaging Filter
  • 435nm Wavelength Bandpass
  • 1.25" Eyepiece Threads
  • 7-Layer Anti-Reflection Multi-Coated
Centered on the 435nm wavelength, the Alpine Astronomical Baader Dark Blue Colored Bandpass Eyepiece Filter can be used by itself or stacked with other filters to enhance your observations when viewing or imaging planets such as Venus, Mars, Jupiter, and Saturn. The optical glass filter is planeoptically polished and treated with seven-layer Phantom Group anti-reflection multi-coatings to improve contrast and clarity while eliminating reflections, scattering, or image dimming. Holding the filter is an black anodized aluminum frame made to fit standard 1.25" eyepieces and other accessories such as diagonals and Barlows.
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Alpine Astronomical FCFDB-1 Overview

Centered on the 435nm wavelength, the Alpine Astronomical Baader Dark Blue Colored Bandpass Eyepiece Filter can be used by itself or stacked with other filters to enhance your observations when viewing or imaging planets such as Venus, Mars, Jupiter, and Saturn. The optical glass filter is planeoptically polished and treated with seven-layer Phantom Group anti-reflection multi-coatings to improve contrast and clarity while eliminating reflections, scattering, or image dimming. Holding the filter is an black anodized aluminum frame made to fit standard 1.25" eyepieces and other accessories such as diagonals and Barlows.

Use
  • For visual and photographic planetary use
  • Aids in better detection of Venus phase
  • Improves view of the Violet Clearing on Mars
  • Enhances the Great Red Spot on Jupiter and contrast between the belts
  • Enhances the contrast between zones on Saturn
  • 70% average transmission bandpass throughput
EAN: 4047825009807

Alpine Astronomical FCFDB-1 Specs

Item Type
1x Dark Blue Filter
Filter Eyepiece Size
1.25"
Transmission Wavelength
435 nm
Coating
Multi-Coated
Filter Material
Glass
Ring Material
Aluminum
Weight
2.1 oz / 59 g
Packaging Info
Package Weight
0.15 lb
Box Dimensions (LxWxH)
3.75 x 3 x 1"

Alpine Astronomical FCFDB-1 Reviews

A Good Visual Lunar and Planetary Filter

By Gary
Rated 5 out of 5
Date: 2026-07-27

The Baader 495nm Yellow filter is good filter to use for visual observations of the Moon and Planets through a telescope. On the Moon it can sharpen the lunar detail a bit, slightly darkens the lunar shadows, and reduces glare and brightness. On Saturn it will help to enhance the visibility of the ring system and ball slightly. When the Planet Mars is in a favorable Perihelion position, it can help enhance the ability see the desert features of Mars. On Venus it can help sharpen the view of Venus phases especially in the Crescent Stage. In rare, very favorable Seeing conditions, the 495nm filter may allow you to see some of the "dark" markings such as terminator clouds on Venus bright cloud layer.

Nice

By John
Rated 5 out of 5
Date: 2020-09-18

Nice to have a filter that works great with my Baader eyepiece.

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