Astrodon Tru-Balance Generation 2 I-Series - LRGB Filter Set - 1.25" Round Mounted

  • Sale
  • Call for Pricing

More on the Way in 14 - 28 business days

Free Shipping
Already have gear? Trade it in for cash or new equipment.

Accessories Added

OPT Telescope Expert

Want Help?

Ask Our Telescope Experts


Astrodon Tru-Balance Generation 2 I-Series - LRGB Filter Set - 1.25" Round Mounted

Astrodon Tru-Balance Gen 2, I-Series, LRGB filters, size 1.25-inch Mounted Filter Set:

Astrodon Tru-Balance RGB filters have revolutionized CCD imaging. Their popularity is due to ease-of-use, high optical throughput and great resulting color for galaxies, star clusters and nebulae. There are two varieties of Tru-Balance filters - E-Series and I-Series.

I-Series filters are designed to approximately equalize the flux of Kodak's Interline CCD detectors, including compensation for the solar photon flux. This means that your RGB color combine weights will be approximately 1:1:1 within perhaps 10-percent. This can never be perfect, but it does allow you to take equal time exposures for your RGB data and also just one corresponding dark exposure time.

This is the first change in Astrodon filter design and fabrication since their inception. Astrodon listened to your requests!

Astrodon filters are parfocal on most systems. The new thickness tolerance of +/-0.025 mm (25 microns) for Gen 2 LRGB filters is a factor of 2 better than Gen 1 filters, and should be parfocal for systems down to f/3.5, if your optical system is well color corrected. The Clear filter is likely a better choice for reflectors, such as a Ritchey-Cretien, rather than refractors or camera lenses.

Halo elimination results from a pioneering design that places both the bandpass layer and the blocking layer on one side of the 1/4-wave substrate and a high performance anti-reflective coating on the other side. As a result there is virtually no internal reflection between these surfaces that can cause halos around bright stars in other filter brands. M45 is one of the most demanding of targets that often leads to halos around bright stars.


Astrodon Tru-Balance Generation 2 Filter Features:

  • RGB filters designed to produce true color for galaxies and stars based upon a G2V (sun-like star) white point.
  • Equal exposure time for each RGB filter leads to equal fluxes and equal color weights (combine ~ 1:1:1).
  • Correct blue-green color for OIII in plane-tary nebula with 1:1:1 RGB color weights for correct star color.
  • Two LRGB designs; E-Series for full-frame, and I-Series for Interline CCDs.
  • Deep red filter in E-Series brings out HII regions in galaxies and better definition of H-alpha in emission nebula.
  • All filters transmit an amazing 98-percent in their pass bands for the highest performance available.
  • All filters are UV and NIR-blocked. No extra filters are needed.
  • Breakthrough design eliminates halos around bright stars.
  • Hardest optical coatings on 1/4-wave fused silica substrates for durability.
  • Coatings extend to the edge (no uncoated rims that need to be blocked) and no edge-sealing is required.
  • Light pollution suppression included in the design.



OPT Product Number: AN-LRGB2-I27R



Filter TypeLRGB
Free ShippingYes
Warranty5 Year Warranty
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:
Italy Italy
kind and fast

Quick mail replies. a note for the dirt on the filters but because they should be individually packed as for the unmounted versions. no scratches.