Chroma 31mm OIII 3nm Telescope Filter

ITEM #
CF-OIII3-31
  • 31mm OIII 3nm Narrowband Filter
  • Parfocal for systems f/4.0 or slower
  • Transmitted wavefront better than 0.25 waves/inch
  • Made in America
  • Filter sizes up to 2-inch come with a complimentary TPO Filter Case (OS-CF2) to keep your filter safe.
  • Sale
  • Regular price $490.00

In Stock
Free Shipping
Add to Wishlist
Already have gear? Trade it in for cash or new equipment.

Accessories Added

OPT Telescope Expert

Want Help?

Ask Our Telescope Experts

1.800.483.6287

Chroma 31mm OIII 3nm Telescope Filter

Please Note: The interference coatings that optical filters are made with are angle-sensitive and shift to the blue with fast focal ratios. This is not a problem for filters 5nm or wider, but the 3nm filters shift enough to compromise transmission at the wavelength line of interest. Chroma has made a set of Ha, OIII and SII 3nm that are optimized for F/3 beams by moving the center wavelength slightly into the red so they will shift slightly to the blue when used in an F/3 beam, thus maximizing transmission at the nominal wavelength. For beams faster than F/3, we recommend using 5nm-wide or wider bands.

The Chroma 31mm OIII 3nm Narrowband Filter is essential for imaging objects, like nebulae, that are rich in ionized oxygen atoms. These line emission filters work extremely well in heavy light polluted areas and allow you image on nights when the moon is up.

Chroma manufactures the highest quality astronomy filters with durable, sputtered hard coating using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.

Highly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity.

SPECIFICATIONS

Bandpass3nm
Filter ShapeRound
Filter Thickness1mm
Filter TypeOIII
Free ShippingYes
Size31mm
Customer Reviews
5.0 Based on 1 Reviews
Write a Review Ask a Question
  • Reviews
  • Questions

Thank you for submitting a review!

Your input is very much appreciated. Share it with your friends so they can enjoy it too!

Filter Reviews:
DM
04/01/2020
David M.
Australia Australia
Chroma O3 filter

Firstly I live in Australia Delivery was lightning fast 7 days. Great service The Chroma filter is performing flawlessly. I only wish I could post you my first light image, it's pretty amazing, the filter is parfocal with my Astrodons which are in the wheel as well. I couldn't be happier with the goods and OPT