TeleVue Bandmate Type 2 H-Beta 1.25" – Line Filter

TeleVue Bandmate Type 2 H-Beta 1,25″ : Lijnfilter: H-beta-lijnfilter voor de moeilijkste nevels

The 1.25-inch Bandmate Type 2 H-beta is the specialist filter for the Horsehead Nebula and the California Nebula: targets that remain virtually invisible for almost any telescope without an H-beta filter.

It is the filter you buy for a short, famous list of objects, and that you never lend out again after that.

How a line filter gains contrast

Emission nebulae emit their light in a handful of narrow spectral lines. Light pollution and the natural airglow do not; they spread out over the entire spectrum. A line filter lets only the nebula lines through and blocks the rest.

The result is not a brighter image, but a darker background from which the nebula emerges. With a Dutch or Belgian sky, that difference is significant.

Type 2: Built by Astronomik to TeleVue specifications

For the Bandmate Type 2 line, TeleVue is collaborating with filter specialist Astronomik. The transmission bands lie exactly on the emission lines, with transmission in the passband exceeding ninety percent and a sharp cutoff outside of it.

The coating is polished and parfocal with TeleVue eyepieces, so focusing is hardly necessary after screwing it on. The filter housing has standard threads, making it compatible with any eyepiece with filter threads of the corresponding size.

What an H-beta filter is used for

The H-beta filter isolates the hydrogen line at 486 nanometers. The list of objects it asks for is short but famous: the Horsehead Nebula, the California Nebula, and some faint reflection nebulae that remain invisible without this filter.

For that handful of targets, it is indispensable, beyond that it does little. An H-beta is therefore the third nebulae filter in a collection, after a UHC and an OIII, and requires a substantial telescope aperture and a dark sky.

Featured accessories

The filter screws into the filter thread of each eyepiece in the corresponding size, and therefore also into the TeleVue eyepieces from our range. For use with a 2-inch diagonal mirror, a 2-inch filter can be inserted directly into the mirror nose.

For whom yes and for whom no

• ✓ The Horsehead Nebula and the California Nebula
• ✓ Large Dobsonian telescopes under a dark sky
• ✓ Who completes their filter set
• As a first or only nebula filter, start with a UHC
• ✗ Small telescopes and a city sky

Specifications

More filters can be found on the Telescope filters page. The complete lineup of this merk is available on the TeleVue merk Page.