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IDAS OIII 6.0nm Narrowband Filter - 50.8mm for CFW

IDAS OIII 6.0nm Narrowband Filter - 50.8mm for CFW

Astro Hutech
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$410.00 You save 8%
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Estimated Arrival: Between Dec 11 and Dec 17. *ETA to USA Only

Shipping & Returns: Satisfaction guaranteed 30 day return policy.


The IDAS Oxygen III filter is designed to isolate the OIII emission bands for best signal-to-noise performance for a wide range of telescope designs.


  • 6.0nm bandpass
  • 6.0 +/- 0.2nm (Measured value)
  • 3.0mm thickness
  • Optimized from F1.65 to any
  • Fully blocks up to 1200nm as illustrated in the plot
  • Comes with the actual measured plot with the unique product code
  • 98% transmission rate (Measured value)
  • Flat top, which maximizes the transmission even for fast optics
  • Out-of-band blocking: 300-1300nm
  • Configurations:
    • 2.5mm or 3.0mm thickness options
    • 3 mount sizes - 48mm, 52mm & 50.8 (for filter wheels)
  • Each filter is individually inspected for quality. The filter response is plotted and provided with each unit.
  • Made in Japan

Filter Plots:


The plots below show the different filter performance with various astrograph designs - refractors vs. telescopes with central obstructions. Note that the nominal response of the filter shifts when considering all angles of incidence to the filter surface caused by the objective's f-ratio, but the filter response is designed to compensate in fast, obstructed optics by picking up more of the shorter wavelength component of the OIII emission line pair. The OIII emissions consist of lines at 495.9 and 500.7 nm, with the shorter wavelength intensity at 40% of the longer wavelength as noted on the plots.


Sample Shots:


Click on the image to see an enlarged view. This shot of the Orion belt region demonstrates the lack of internal reflections around bright stars.


We know that once you've placed your order, you are anxious to receive it! We make every effort to get your order shipped out to you as quickly as possible.

As soon as you place your order, you will receive an order confirmation e-mail. This means that we have received your order in our system and pre-authorized your credit card for the purchase. We will process the charges to your credit card and your order will ship within five business days from the date of your order. We will send you tracking information within 24 hours of your order leaving the warehouse to the e-mail address you provided when checking out.  If you do not receive tracking information from us within six business days of your order, feel free to follow up with us at

Standard shipping time in the US is between 3-5 business days, though it can vary slightly depending on the destination. We typically For updates on your shipment you can enter your tracking number here.

We distribute nationwide via UPS and Fedex. Unfortunately, at this time we are not able to provide expedited or international shipping.

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