SVBONY SV132 2″ H-Beta 25nm Visual Nebula Filter

Product Overview

The SVBONY SV132 is a 2″ H-Beta narrowband filter for visual observing. It passes a 25 nm ± 2 nm band centred on 486 nm ± 2 nm — the hydrogen-beta emission line — at a published 90% peak transmission, and blocks to OD3 across 300–1100 nm. The filter is coated on a 1.85 mm B270 substrate with a 44 mm clear aperture, 60/40 surface quality and 1/4λ surface parallelism, mounted in a metal cell with standard 2″ threads.

Who It's For

This is a good match if you observe faint emission nebulae visually through a larger-aperture telescope under dark skies, and want the handful of objects that shine mainly in H-beta — the Horsehead, California and Cocoon nebulae among them — to stand out from the background.

Key Features & Design

• 486 nm H-beta passband: 25 nm FWHM isolates the blue hydrogen-beta line and suppresses the rest of the visible spectrum.
• 90% peak transmission: keeps as much of the target's light as possible at the eyepiece.
• OD3 blocking, 300–1100 nm: broad out-of-band suppression.
• B270 substrate, 1.85 mm: 60/40 surface quality, 1/4λ surface parallelism, 30″ parallelism.
• 44 mm clear aperture: sized for 2″ eyepieces and diagonals.
• Metal cell with 2″ threads: precise threading that seals against light leaks.

Recommended Uses

• The Horsehead Nebula (B33) against the IC 434 glow — the classic H-beta target.
• The California Nebula (NGC 1499), whose large, faint outline benefits from a low-power 2″ eyepiece.
• The Cocoon Nebula (IC 5146) and other H-beta-bright emission regions.

Compatibility and Accessory Notes

• Threads: standard 2″ filter thread; screws into 2″ eyepiece barrels and threaded 2″ diagonal nosepieces.
• Aperture: SVBONY recommends a large-aperture telescope; small apertures do not gather enough light for these faint targets through a narrow passband.
• Sky: the target nebulae are best seen from dark sites.
• Need the 1.25″ size? SVBONY also makes the SV132 H-Beta in 1.25″.

Good to Know Before You Order

• Specialist filter: H-beta enhances a short list of objects. For broader nebula work, an OIII or UHC-type filter covers more targets.
• Aperture matters: SVBONY does not recommend it for small-aperture telescopes.
• Visual filter: it is designed for eyepiece use.

Frequently Asked Questions

Is it difficult to set up?

No. It threads onto the barrel of a 2″ eyepiece or into the nosepiece of a threaded 2″ diagonal.

What can I see with an H-Beta filter?

Mainly emission nebulae that are bright in hydrogen-beta, such as the Horsehead, California and Cocoon nebulae.

What size telescope do I need?

SVBONY recommends a large-aperture telescope; small apertures are not recommended with this filter.

Will it help in light-polluted skies?

Its targets are best observed from dark sites; the filter boosts contrast on them but does not replace a dark sky.

Bottom Line

In short: a 2″, 25 nm H-Beta filter at 486 nm with 90% peak transmission, made for bringing out the Horsehead, California and Cocoon nebulae in a larger telescope under dark skies.

Performance Data

SVBONY's published transmission data for the SV132: