Optolong Variable Transmission Polarizing Filter - 2"
- This item is currently on backorder from the manufacturer.
- Orders are fulfilled in the order they are received once inventory arrives.
Stock count is accurate & shown in real time.
- This item is out of stock.
- Sign up for back-in-stock alerts to be notified when this item becomes available.
- This item is out of stock.
- We have no ETA from the manufacturer at this time.
- Sign up for back-in-stock alerts to be notified when this item becomes available.
Lower 48 States:
Orders over $50 ship free within the Lower 48 using a carrier and service we select based on your items and delivery location. Faster shipping options may be available at checkout.
U.S. Outside the Lower 48 (AK, HI, PR):
Free shipping on orders over $50 applies to many—but not all—items. Add items to your cart and enter your ZIP code to see available shipping options and any costs.
International Orders:
Free shipping does not apply to international orders. You’ll see available shipping options and costs during checkout. Some items can’t be shipped internationally due to size or manufacturer restrictions. Duties, taxes, brokerage fees, and tariffs are not included and are the customer’s responsibility.
A. About Optolong's Variable Polarizer Filter
A variable polarizing Moon filter consists of two single polarizing filters coupled together. One of these has threads to attach to the bottom of eyepieces or other threaded adapter barrels, and the second filter can freely rotate over 360-degrees, thus allowing you to control the brightness of the image over a wide range. You simply rotate the lower filter until the image brightness is pleasing and comfortable for you, given your telescope aperture and the phase of the Moon. While primarily meant for use while observing the Moon, this filter can also help with observations of other bright objects like Venus and Jupiter. Please note, however, that unlike some other similar filters on the market, the two Optolong filter components of this item cannot be separated.
B. Technical Specifications
- All surfaces are fine optically polished, accurate to 1/4 wavelength or better, and parallel to within 30 seconds or arc.
- 2mm thick Schott B260 optical glass substrate material.
- Very high surface quality of 60/40 or better (US Military Spec MIL-O-13830).
C. Optical Coating Specifications
- Multi layer anti-reflection coated.
- 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) so that there is no deviation due to temperature changes during use.
- Precise and homogeneous coatings ensure high values of desired passband and blocking of unwanted offband.
- Every single filter is tested and passed by Optolong before shipping to dealers.
D. Other
- 2" astronomy filter with standard M48x0.75 male filter thread.
- Ultra-thin filter cell to minimize vignetting; clear optical aperture of 45mm.
- Precision CNC-machined metal filter cell with sand blasted black anodized finish, anti-reflection treatment, and laser engraving.
- High quality protective plastic storage case.
WARNING: Optolong filters are not designed for direct solar observation. NEVER use these filters for observing the Sun, or permanent eye and equipment damage will result.
Useful Resources
Filter Cell Specifications
D = Filter Cell Diameter = 50.7 mm / 2.0 in
T = Total Filter Height = 7.1 mm / 0.28 in
C = Filter Cell Height (Excluding Male Thread) = 4.5 mm / 0.18 in
M = Male Thread Length = 2.6 mm / 0.1 in
F = USABLE Female Filter Thread Length = Not threaded, so you cannot stack additional filters
S = Glass Substrate Thickness = 1 mm / 0.04 in
CA = Clear Aperture = 45 mm / 1.77 in
Other Information
- Country of Manufacture: China
A. About Optolong's Variable Polarizer Filter
A variable polarizing Moon filter consists of two single polarizing filters coupled together. One of these has threads to attach to the bottom of eyepieces or other threaded adapter barrels, and the second filter can freely rotate over 360-degrees, thus allowing you to control the brightness of the image over a wide range. You simply rotate the lower filter until the image brightness is pleasing and comfortable for you, given your telescope aperture and the phase of the Moon. While primarily meant for use while observing the Moon, this filter can also help with observations of other bright objects like Venus and Jupiter. Please note, however, that unlike some other similar filters on the market, the two Optolong filter components of this item cannot be separated.
B. Technical Specifications
- All surfaces are fine optically polished, accurate to 1/4 wavelength or better, and parallel to within 30 seconds or arc.
- 2mm thick Schott B260 optical glass substrate material.
- Very high surface quality of 60/40 or better (US Military Spec MIL-O-13830).
C. Optical Coating Specifications
- Multi layer anti-reflection coated.
- 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) so that there is no deviation due to temperature changes during use.
- Precise and homogeneous coatings ensure high values of desired passband and blocking of unwanted offband.
- Every single filter is tested and passed by Optolong before shipping to dealers.
D. Other
- 2" astronomy filter with standard M48x0.75 male filter thread.
- Ultra-thin filter cell to minimize vignetting; clear optical aperture of 45mm.
- Precision CNC-machined metal filter cell with sand blasted black anodized finish, anti-reflection treatment, and laser engraving.
- High quality protective plastic storage case.
WARNING: Optolong filters are not designed for direct solar observation. NEVER use these filters for observing the Sun, or permanent eye and equipment damage will result.
A. About Optolong's Variable Polarizer Filter
A variable polarizing Moon filter consists of two single polarizing filters coupled together. One of these has threads to attach to the bottom of eyepieces or other threaded adapter barrels, and the second filter can freely rotate over 360-degrees, thus allowing you to control the brightness of the image over a wide range. You simply rotate the lower filter until the image brightness is pleasing and comfortable for you, given your telescope aperture and the phase of the Moon. While primarily meant for use while observing the Moon, this filter can also help with observations of other bright objects like Venus and Jupiter. Please note, however, that unlike some other similar filters on the market, the two Optolong filter components of this item cannot be separated.
B. Technical Specifications
- All surfaces are fine optically polished, accurate to 1/4 wavelength or better, and parallel to within 30 seconds or arc.
- 2mm thick Schott B260 optical glass substrate material.
- Very high surface quality of 60/40 or better (US Military Spec MIL-O-13830).
C. Optical Coating Specifications
- Multi layer anti-reflection coated.
- 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) so that there is no deviation due to temperature changes during use.
- Precise and homogeneous coatings ensure high values of desired passband and blocking of unwanted offband.
- Every single filter is tested and passed by Optolong before shipping to dealers.
D. Other
- 2" astronomy filter with standard M48x0.75 male filter thread.
- Ultra-thin filter cell to minimize vignetting; clear optical aperture of 45mm.
- Precision CNC-machined metal filter cell with sand blasted black anodized finish, anti-reflection treatment, and laser engraving.
- High quality protective plastic storage case.
WARNING: Optolong filters are not designed for direct solar observation. NEVER use these filters for observing the Sun, or permanent eye and equipment damage will result.
Useful Resources
Filter Cell Specifications
D = Filter Cell Diameter = 50.7 mm / 2.0 in
T = Total Filter Height = 7.1 mm / 0.28 in
C = Filter Cell Height (Excluding Male Thread) = 4.5 mm / 0.18 in
M = Male Thread Length = 2.6 mm / 0.1 in
F = USABLE Female Filter Thread Length = Not threaded, so you cannot stack additional filters
S = Glass Substrate Thickness = 1 mm / 0.04 in
CA = Clear Aperture = 45 mm / 1.77 in
Other Information
- Country of Manufacture: China
| Free Shipping Graphic | Free US Shipping |
|---|---|
| Hide Found a better Shipped Price on Frontend? | No |
Optolong Variable Transmission Polarizing Filter - 2"