Optec - Astrodon "I"-series LRBG filter set, 50mm diameter x 3mm thick (unmounted)
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%. 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.
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.
Optec can supply a full range of filters for the IFW wheel. Filters are easily and safely mounted in the new IFW filter wheel by use of delrin plastic holding tabs and spacers. Filters from 1 to 5 mm in thickness can be accommodated with use of delrin ring spacers. Because the flexible tab and not the head of the screw holds the filter in place, it is impossible for the filter to be damaged by excess over tightening. An ample supple of tabs and spacers are supplied with each filter wheel.
Filter wheels for both 50mm diameter and 2-inch diameter are available. For special purposes, an 8 position wheel configured for 1-inch filters is offered.