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Moon&Skyglow Filter 2”

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Moon&Skyglow Filter 2”

Moon&Skyglow Filter

Moon & Skyglow filter is designed to darken the background sky by blocking light transmission from skyglow 589nm and many street light emissions from artificial light. Its high efficiency preserves image brightness, reveals more details and increases contrast of moon, galaxies, nebulae and globular star clusters.

Main Use and Performance

  • Ideally it is quite versatile filter for visual observation and astrophotography on planetary 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
  • Infrared wavelength 700-1100nm cut-off

Coating Parameter

  • Multi-layers anti-reflection coating
  • 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


  • Plastic PP Case | Imported High Pressure EVA Case Lining | Silver Cardboard Box | High Density Sponge Carton Lining


  • Standard 1.25” & 2”

Spectral Curve

Moon sky



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.


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.



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. 

Filed under: Eyepieces & Accessories