Astrodon LRGB Filter Set - I Series

Luminance and Blue Filters are the same in both the E and I series. Only the Red and Green filters differ.

Astrodon LRGB Gen2 I-Series Tru-Balance Filters are designed to approximately equalize the flux of Interline CCD detectors (formerly Kodak), including compensation for the solar photon flux. The I-Series filters compensate for the lower red response of these Interline detectors affecting the design of the Green and Red filters. The Luminance and Blue filters are the same as those in our E-Series. This means that your RGB color combine weights will be approximately 1:1:1 within perhaps 10% for equal length exposures. This can never be perfect, but it does allow you to take one exposure time for all of your RGB data and therefore, only just one corresponding dark exposure time. Again, this saves you precious imaging time and thus, simplifies your imaging.

• Set includes Luminance (NIR/UV-blocked colorless), Red, Green and Blue filters
• 1.25″ mounted, 31, 49.7 mm dia.
• 3 +/-0.025 mm single 1/4 wave fused silica substrate before coating
• 30 arcsec parallelism
• ~1:1:1 color combine weights for G2V white-point for Kodak Interline detectors
• Equal RGB exposures and one dark time
• Better color separation (see spectra)
• Better color rendition for galaxies based upon color theory
• Significant reflection and star halo reduction
• Spectral “gap” between green and red filters to reduce the effects of light pollution
• Highest efficiency blue filter with less UV
• Correct “teal” OIII color for planetary nebula (OIII signal >97% in blue and green)
• Parfocal with Astrodon‘s high-performance narrowband and near-IR Luminance filters
• Ultra-hard and durable sputtered coatings coated to the edge of each filter
• Proudly made in the U.S.A.

Notice that Astrodon filters are coated to the edge. Other filters leave an uncoated “rim” near the edge that must be blocked by a mask or the design of the filter wheel. Our approach minimizes stray light from polluting your image.

A common question: Should I get E-Series or I-Series LRGB filters?

The answer is that it depends on your camera sensor. Progressive Scan camera sensors ( including both Front Illuminated and Back Illuminated sensors) use the E-Series LRGB filters. Interline Transfer sensors should use the I-Series LRGB filters. Finding out what type sensor your camera uses can be difficult. This information is not often included in the specifications or even the manual. So it is best to check with the sensor manufacturer. If you absolutely can’t find out, then go with the E-Series and you will be fine.