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Oxygen III Šmidt-Kasegreno filtras

€163.00



  • 0 Vienetų sandėlyje
  • Gamintojas: Orion (USA)

The legendary Lumicon 1.25in OIII narrow band-pass filter isolates just the two doubly ionized oxygen lines (496 and 501nm lines) emitted by diffuse, planetary and extremely faint nebulae. Thus, these faint objects become much more visible against the blackened background of space. The Lumicon Oxygen III Filter produces near-photographic views of the Veil, Ring, Dumbbell and Orion nebula, among many other objects. Performs well under both light-polluted and dark skies. Recommended for telescopes 10" or larger in aperture.
To ensure that your Lumicon filter remains the World's Best, the strictest quality control standards are employed throughout the production process. Each Lumicon Oxygen III Filter is individually inspected and proudly inscribed with the percentage of light transmittance of the two OIII emission lines.


The Deep Sky , Hydrogen-Beta , Oxygen III , and Ultra High Contrast Filters are the result of 20 years of steady design improvements, and continue to deliver the highest performance of all anti-light pollution filters obtainable today. The following information recommends which filter to use on which celestial objects, and explains how filter transmissions differ.

Objects

Examples

Best Filter for Viewing

Best Filter for Photography

Stars & Star Clusters

M13, M11

None

Deep Sky

Diffuse Nebulae

Lagoon, Swan

OIII (light polluted sky) Deep Sky, UHC (dark sky)

Deep Sky

Planetary Nebulae

Dumbbell, Ring

OIII (light polluted sky) Deep Sky, UHC (dark sky)

Deep Sky

Faint Planetary Nebulae

NGC 7293, Abell 33, Jones 1

OIII

Deep Sky

Reflection Nebulae

Pleiades, Trifid

Deep Sky

Deep Sky

Spiral Galaxies

M33, M101

None

Deep Sky

Faint Nebulae

Veil, Rosette, N. American

OIII (light polluted sky) Deep Sky, UHC (dark sky)

Deep Sky

Extremely Faint Nebulae

California, Horsehead

H-Beta

Night-Sky H-Alpha
Deep Sky

Oxygen III Filter

Narrow band pass filter (11nm) isolates just the two doubly ionized oxygen lines (496nm and 501nm) emitted by planetary and extremely faint nebulae.

Produces near-photographic views of the Veil, Ring, Dumbbell, Orion, plus many other nebula.

Exit Pupil Specifications:

The exit pupil of a telescope is a measure of specific magnification, which differs from absolute magnification, and which determines the surface brightness of an extended object image. Exit pupil diameter may be expressed as the quotient of eyepiece focal length divided by the telescope's focal ratio. For example, a 32mm eyepiece used on an f/10 telescope will have a 3.2mm exit pupil. Each Lumicon filter has an optimum eyepiece exit pupil range shown below.

Filter Type

Deep Sky

UHC

OIII

H-Beta

Bandpass

90nm

22-26nm

10-12nm

8-10nm

Optimum Exit Pupil (Light-polluted sky)

0.5-2mm

1-4mm

2-5mm

3-7mm

Optimum Exit Pupil (Dark sky)

1-4mm

2-6mm

3-7mm

4-7mm

Notice:

As filter bandpass decreases, optimum exit pupil size tends to increase. To determine the best eyepiece focal length to use with a given filter, simply multiply the Exit Pupil value shown above by your telescope's focal ratio. For example, if you are using the Lumicon H-Beta filter at a dark site and your telescope has an f/6 focal ratio, the best range of eyepiece focal lengths to use with this filter is [(4 to 7) x 6] = 24mm to 42mm.

Filter Construction:

Lumicon nebula filters are made using thin-film dielectric coatings on optically flat glass. These exclusively designed dielectric coatings consist of over 30 alternating layers of several different materials. Each layer is about a wavelength of light thick and has a thickness accurate to 2 - 3 angstroms. Lumicon nebula filters include anti-reflection coatings on both sides to prevent ghosting and increase light transmittance. They also have a hard, electron-beam deposited coating for mechanical protection. While still delicate, Lumicon filters may be carefully cleaned with isopropyl alcohol, or Lumicon’s Advanced Cleaning Kit.

Mechanical Design:

These filters thread directly into most eyepieces and telescope accessories. Threads are standard for 1.25" filters. 48mm filters are standard for 2" O.D. eyepieces.

Bandpass:

These Lumicon filters reject man-made and natural light pollution. Mercury light pollution occurs at 365, 405, 436, 546, 577, and 617nm. High-pressure sodium streetlights emit at 570, 583, 600, and 617nm. Natural airglow occurs at 558 and more weakly at 630nm. There is a window of greatly reduced light pollution from 440nm (blue) to 540nm (green). The Lumicon Deep Sky Filter has a wide 90-100nm bandpass for most of this range (441-535nm) to yield maximum transmission of light from stars and galaxies. The UHC Filter has a narrow 22nm bandpass through 484-506nm. The OIII Filter has a very narrow 11nm bandpass for 495-501nm, and the H-beta Filter has the narrowest bandpass of all - only 8nm centered at 486nm. The narrower the bandpass, the higher the rejection of light pollution and the blacker the skies. However, a narrower bandpass also means fainter star images. Nevertheless, the Deep Sky Filter has high transmission for the photographic red nebula emission lines.

Nebula Emission Lines:

The main visible radiation from emission nebulae consists of doubly ionized oxygen near the wavelength of 500nm. There is also weaker emission due to hydrogen-beta at 486nm. The invisible but photographically important emission of red hydrogen-alpha and ionized nitrogen occur near 657nm.




Ši prekė į katalogą buvo įtraukta Penktadienis 04 rugsėjo, 2009.