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.
Astrodon Tru-Balance Gen 2 - E-Series - LRGB 1.25" Mounted Filter Set
E-Series filters are designed to approximately equalize the flux of Kodak's full-frame (E-Series) 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%. 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.
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%. 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 +/-0.025mm (25 microns) for Generation 2 LRGB fitlers is a factor of 2 better than Gerneration 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 Ritchey-Cretiens, 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% in their passbands for the highest perform-ance 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.
- Additional Information
SKU AN-LRGB2-E27R Manufacturer Astrodon Type of Filter LRGB Filter Usage Imaging Single or Set? Filter Set Filter Size 1.25" Filter Shape Round Filter Mounted? Mounted Warranty 5 Year Warranty
- Included Items
- Astrodon Tru-Balance Generation 2 E-Series - LRGB 1.25" Mounted Filter Set:
- 1.25" Luminance
- 1.25" Red
- 1.25 Green
- 1.25" Blue
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