O-III 25nm Light Pollution Filter 1.25”

Description

O-III 25nm Light Pollution Filter 1.25”
O-III 25nm Light Pollution Filter 1.25”
O-III 25nm Light Pollution Filter
Narrowband OIII filter is designed for nebula observation allowing 25nm bandwidth of light centered on a wavelength of 500nm through, which corresponds to OIII emission lines, and reducing the transmission of certain wavelengths of light, specifically those produced by artificial light including mercury vapor, and both high and low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).
OIII emits 495.9nm and 500.7nm and it is a blue-green colored filter. Many of images of planetary nebula and supernova remnants are taken only with H-alpha and OIII filters. They show great structural details, but have natural colors, looking like an RGB image.
Main Use and Performance
Suitable for visual observation on most emission nebulae, planetary nebulae and supernova remnants
Suitable for viewing on bright nebulae like M42 Orion Nebula in heavy light pollution
Use with a large aperture telescope under clear and dark viewing conditions with good seeing
Narrowband filter do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.
WARNING:
The filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER. You would be BLIND if you fail to observe the warning.
Technical Data
Schott substrate material
Thickness 2.0mm
Surface Quality: 60/40 (Refer to MIL-O-13830)
Fine-optically polished to ensure accurate 1/4 wavefront and <30 seconds parallelism over the both surfaces
90% transmission at major OIII line 495.9nm and 500.7nm
Precision off-band blocking, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm)
Coating Parameter
Non-cementing optical substrate coating
Electron-beam gun evaporation with Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL(central wavelength) no deviation affected by temperature change
Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band
Filter Cell
Ultra-thin filter cell minimize vignetting by maximize possible clear aperture (clear aperture is 26mm for 1.25”; 45mm for 2”)
Aerometal Material | Precise CNC Machining | Sand Blasting Process | Black Anodized Finish | Extinction Treatment to Prevent Reflection | Laser Engraving No Fading
Package
Plastic PP Case | Imported High Pressure EVA Case Lining | Silver Cardboard Box | High Density Sponge Carton Lining
Size
Standard 1.25” & 2” | Round 36mm Unmounted
Spectral Curve
The Major Emission Lines of Nebulae
H-β486.1nm OIII 495.9nm OIII 500.7nm H-α656.3nm
The Major Emission Lines of Artificial Light Pollution
Hg 435.8nm 546.1nm 577nm 578.1nm
Na 598nm 589.6nm 615.4nm 616.1nm
Shipping
Shipping cost:
We ship via United States Postal Service (USPS). The shipping calculations occur upon checkout.
Delivery time:
Most products ship within 2 business days.
Payment
We accept the following payment methods:
Paypal
We accept any major credit card, including American Express, Visa, MasterCard, and Discover, debit cards tied to a checking account, and prepaid cards
Please contact us if you have any questions.
Service
All of our products are new product and are shipped in good condition in packaging intended for them to arrive in good condition.  You can return any of our products within 90 days for any reasons and receive a full refund if the instructions have been followed. Included with the filter are instructions for use and care.