Meade Series 4000 Broadband Nebular Filters:
For dramatic increase in visual and
photographic detail in deep-space
emission and reflection nebulae.
Meade Series 4000 Broadband Nebular Filters incorporate the very latest in
interference coatings technology. Each Broadband Nebular filter #911B includes more than 40 coating layers to reject, with
precision, unwanted light from urban light pollution while
passing critical nebular emissions with minimal reduction.
Technical Basis of Meade Broadband
As shown in the transmission graph, Meade Broadband Nebular Filter strongly rejects the light of sodium- and mercury-vapor lights as
well as natural airglow and auroral emissions. Conversely, the strong nebular
emission spectral lines, transmitting in the visually sensitive regions
primarily at 486nm (Hydrogen Beta) and 496 to 501nm
or OIII), are passed
through the filter with
high transmission percentages.
of the filter is that nebular
light reaching the
eye is observed
visually in dramatically
increased detail, while
the effects of unwanted
city lights are greatly
The Meade Broadband Filter also passes
photographically- important Hydrogen Alpha nebular light at
656nm largely unattenuated, making the filter a valuable aid
in the photography of deep-space emission nebulae as
well. The contrast between galaxies and the night-sky
backdrop is also typically enhanced by the filter, but
because galaxies emit light in a much broader range of
wavelengths than nebulae, the effect is generally not as
dramatic in these cases.
Meade Series 4000 Broadband Nebular Telescope Filter #911B (item 07524):
Threads onto the rear
cells of Meade
LX-Series mirrorlens telescopes and onto Meade ED
Apochromatic Refractors (using the Universal Thread Adapter), as well as to the
rear cells of other Schmidt-Cassegrain brands. In this way the telescopes are
converted into a basic "nebular mode," for visual observing or for photography
with the T-Adapter or Off-Axis Guider.
Clear aperture for Meade 911B Filter is 36mm.