Enjoy the most dazzling views of nebulae with your Celestron
Origin when you add this H-alpha H-beta OIII (Hα-Hβ-OIII) imaging filter. This
specialized filter allows high throughput of light wavelengths in emission
nebulae while blocking other wavelengths that could diminish image quality and
detail. The result is bright, colorful nebulae images that "pop” with detail against
the black sky background.
How does the Nebula Filter for Origin work? Emission nebulae
primarily emit at discrete wavelengths of light—Hα at 656nm, Hβ at 486nm, and
OIII at 496/501nm. By strategically transmitting only these wavelengths of
light and blocking the rest of the spectrum, the filter dramatically reduces
the effect of light pollution. The "bad” light is blocked while the "good”
light associated with emission nebulae passes through to Origin’s sensor.
You’ll immediately notice much higher contrast in your images, especially
from your light-polluted backyard! And since the transmission at the critical
wavelengths is so high, the nebula will not be dimmed—only the background will
be blacker. You’ll also notice some contrast improvement in images of nebulae
from darker skies, as the filter serves well in blocking natural skyglow.
Nebula Hunting
The Nebula Filter is perfect for imaging emission nebulae like the
North America Nebula (NGC 7000), Lagoon Nebula (M8), Orion Nebula (M42), the
Carina Nebula (NGC 3372), and dozens more. The imaging filter offers maximum
light transmission in the key Hα-Hβ-OIII wavelengths, producing high contrast
for emission nebulae like these.
The transmission spectrum for the Nebula Filter is 85% or greater at key wavelengths (486nm, 496nm/501nm, 656nm) and less than 0.5% transmission elsewhere. As a narrowband filter, it blocks much of the visible spectrum and only lets these specific wavelengths through. Because of this, you should not use this filter while observing or imaging broadband emission objects, such as galaxies and star clusters. For those objects, you’ll achieve the best results by removing the nebula filter and reinstalling Origin’s clear optical window.
Other similar imaging filters on the market have much narrower
bandpasses at the critical Hα-Hβ-OIII wavelengths. Unfortunately, these filters
block much of the incoming Hα-Hβ-OIII light for an f/2.2 optical system like Origin’s
6” RASA. This is because a RASA brings light into the filter at a steeper
angle, which causes a spectral shift. If you use filters not explicitly
designed for use at f/2.2, some of the light from the nebula will be blocked,
resulting in a dimmer image. The Nebula Filter for Origin was custom-engineered
to work at f/2.2, so none of the "good” light from the nebula is inadvertently
blocked by the filter.
Body and Storage
The filter features a machined aluminum black anodized cell with a
knurled rim for easy grip during installation. We’ve added anti-reflection
coatings to help suppress reflections on the glass. The filter fits directly
into the filter drawer in the Celestron Origin’s front lens cell, where the optical
window sits. Simply remove the clear window and replace it with the filter.
Origin maintains its optical performance across the entire system with the
filter installed. No other adapter is needed.
Each filter comes with a foam-lined plastic storage case to safely
store the filter or the optical window glass that came with your Celestron
Origin when not in use.
Celestron tests every Nebula Filter for Origin individually to
verify its performance. Along with your filter, you will receive a spectral
transmission graph (like the one pictured above) showing the results of your filter’s
test and verifying it performs as expected throughout the spectrum.
Glass type
|
Schott B270
|
Glass thickness
|
2mm (0.078”)
|
Clear aperture
|
24mm (0.94”)
|
Coatings
|
Dichroic multi-bandpass and multi-layer
anti-reflection coatings
|
Filter cell
|
Aluminum, black anodized
|
Filter threads
|
M28.5 x 0.6, fits standard 1.25” filter
threads
|
Height of cell
|
6mm total (4mm shoulder height, 2mm thread
height)
|