Meade Series 4000 Filters

Meade Series 4000 Filters

Meade Broadband Nebular Filter.

For dramatic increase in visual and photographic detail in deep-space emission and reflection nebulae.
 

Meade Series 4000 Nebular Filters incorporate the very latest in interference coatings technology. Each filter 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 the Meade Broadband Nebular Filter: The 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, or Hß) and 496 to 501nm (Oxygen-III, or OIII), are passed through the filter with high transmission percentages. The effect 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 reduced. 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.

Two models of Broadband Nebular Filters are available:

#908B: Threads into the barrels of all Meade 1.25" eyepieces, and into the barrels of most other 1.25" brands. Clear aperture: 26mm
#911B: Threads onto the rear cells of Meade LX-series mirror-lens 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 is 36mm.

Meade Narrowband Nebula Filter

Unlike the wide transmission band characteristics of the Broadband Nebular Filters, Meade Narrowband Filters zero in on the three most important visible wavelengths emitted by deep-space emission nebulae: the two spectral lines of Oxygen III at 496 and 501nm and the Hydrogen Beta line at 486nm. Virtually all unwanted city light emissions are rejected by factors of 99.9+%.

Because of its narrow bandpass characteristics, the Narrowband Nebular Filter achieves striking levels of contrast between the nebula itself and the surrounding dark-sky environment: objects such as the Orion Nebula (M42), the Lagoon Nebula (M8), and the Omega Nebula (M17) are observed as they would normally appear through telescopes of several inches larger aperture. Tenuous, faint outer extensions of these objects now become readily observable—often to the point where the visible mass of the nebula is more than doubled in diameter. Planetary nebulae such as the Ring Nebula (M57), the Dumbbell Nebula (M27), and the Saturn Nebula (NGC7009) similarly display dramatically-heightened levels of contrast and observable detail. Faint, insignificant patches of nebulosity that heretofore were near the limit of observability are now viewed with ease.

The Meade Narrowband Nebular Filter should be viewed as a complement to, not as a substitute for, the Broadband Filter. The Broadband Filter enhances the performance of a much wider range of nebular objects; the Narrowband Filter improves contrast and visible detail on fewer objects, but in these more limited cases it does so to a most dramatic level. Because of the very narrow range of total light energy transmitted, the Narrowband Filter is not intended as a photographic filter. Visual effects of the Narrowband Filter are most pronounced when the filter is used with eyepieces of 25mm focal length and longer.

#911N: Threads onto the rear cells of Meade LX-series mirror-lens telescopes and onto Meade ED Apochromatic Refractors, using the Universal Thread Adapter. Also threads to other brands of SCT's as well. Clear aperture: 36mm.

You are buying from an authorized Meade UK dealer.