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IDAS H-alpha 6.8nm High Speed Filter - 3.0mm Thickness
IDAS H-alpha 6.8nm High Speed Filter - 3.0mm Thickness
IDAS H-alpha 6.8nm High Speed Filter - 3.0mm Thickness
IDAS H-alpha 6.8nm High Speed Filter - 3.0mm Thickness

IDAS H-alpha 6.8nm High Speed Filter - 3.0mm Thickness

Astro Hutech
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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 Hydrogen-Alpha family of filters allows astrophotographers to select an Hα filter optimally tailored to their equipment.
The High-Speed Version is more optimized for optics between F2.5 and F3.5 such as Epsilon Series and regular camera lenses. 

The IDAS Ha-6.8 family includes 3 options - STD (Standard), HS (High Speed) and UHS (Ultra High Speed) with bandpasses adjusted to accommodate the f-ratio of different speed astrophotographs. In additon each class comes in two different glass thicknesses - 2.5 mm & 3.0 mm.

  • STD - recommended for most regular scopes
  • HS - ideal for the optics between F2.0 and F3.5 such as Takahashi Epsilon Series, RASA11, and standard camera lenses
  • UHS - highly optimized for the optics for F2.2 or faster such as RASA8 and HyperStar Series
Prices are the same across the filter family regardless of the option selected. Filters are designed to fit in 50.8mm QHY, ZWO and ATIK filter carousels.
  • Ha 6.5 +/- 0.1nm (measured value)
  • 98% transmission rate (measured value)
  • Class HS
  • 3.0mm thickness
  • Optimized for F2.5 to F3.5 such as Epsilon Series and regular camera lenses
  • Fully blocks up to 1200nm as illustrated in the plot
  • Made in Japan

Detailed Filter Plots:

The plots below show the different filter performance with various astrograph designs - refractors vs. telescopes with central obstructions.


STD- refractor STD- telescope with central obstruction (CO) HS- refractor HS- telescope with central obstruction (CO) UHS- refractor UHS- telescope with central obstruction (CO)



Reflection Test Sample:

This test (200 second exposure) shows clean images of bright stars in the field, indicating good anti-reflection (AR) design.





Examples from Bortle 8 skies (5-minute exposures):




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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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