Astrodon filters

Tru-Balance LRGB

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.

E-Series filters are designed to approximately equalize the flux of Kodak's full-frame (E-Series) CCD detectors. While the 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.

Select size / fitting E-Series Astrodon E-Series Tru-Balance LRGB filter set (1.25" mounted) - £299.00 Astrodon E-Series Tru-Balance CRGB filter set (1.25" mounted) - £299.00 Astrodon E-Series Tru-Balance LRGB filter set (50mm diameter) - £450.00 Astrodon E-Series Tru-Balance CRGB filter set (50mm diameter) - £450.00 Astrodon E-Series Tru-Balance LRGB filter set (50mm square) - £809.00 Astrodon E-Series Tru-Balance CRGB filter set (50mm square) - £809.00 I-Series Astrodon I-Series Tru-Balance LRGB filter set (1.25" mounted) - £299.00 Astrodon I-Series Tru-Balance CRGB filter set (1.25" mounted) - £299.00 Astrodon I-Series Tru-Balance LRGB filter set (50mm diameter) - £450.00 Astrodon I-Series Tru-Balance CRGB filter set (50mm diameter) - £450.00 Astrodon I-Series Tru-Balance LRGB filter set (50mm square) - £809.00 Astrodon I-Series Tru-Balance CRGB filter set (50mm square) - £809.00

Narrowband filters

Narrowband (NB) filters enhance contrast of emission objects by accepting only a narrow range of wavelengths around the emission lines of hydrogen (H-a, 656 nm), oxygen (OIII, 501 nm), sulfur (SII, 672nm) and others. They can be used to image when the moon is up, thereby extending imaging time. They can be used in light-polluted locations.

The narrow range of wavelengths is defined as the FWHM (full-width at half- maximum intensity). Narrower filters decrease the background noise. However, narrower filters are more difficult to manufacture consistently, and are thus more expensive. Furthermore, it is difficult to maintain high transmission through the bandpass of the filter as it becomes narrower. If the peak transmission decreases as the filter is made narrower, the emission signal decreases and the gain in S/N (signal-to-noise) is not realized. Astrodon has achieved this goal of high transmission for narrower filters.

Select your Ha filter 5nm Astrodon 5nm Ha filter (1.25" mounted) - £203.00 Astrodon 5nm Ha filter (50mm diameter) - £432.00 Astrodon 5nm Ha filter (50mm square) - £499.00 3nm Astrodon 3nm Ha filter (1.25" mounted) - £290.00 Astrodon 3nm Ha filter (50mm diameter) - £639.00 Astrodon 3nm Ha filter (50mm square) - £739.00

Select your OIII filter 5nm Astrodon 5nm OIII filter (1.25" mounted) - £203.00 Astrodon 5nm OIII filter (50mm diameter) - £432.00 Astrodon 5nm OIII filter (50mm square) - £499.00 3nm Astrodon 3nm OIII filter (1.25" mounted) - £290.00 Astrodon 3nm OIII filter (50mm diameter) - £639.00 Astrodon 3nm OIII filter (50mm square) - £739.00

Select your SII filter 5nm Astrodon 5nm SII filter (1.25" mounted) - £203.00 Astrodon 5nm SII filter (50mm diameter) - £432.00 Astrodon 5nm SII filter (50mm square) - £499.00 3nm Astrodon 3nm SII filter (1.25" mounted) - £290.00 Astrodon 3nm SII filter (50mm diameter) - £639.00 Astrodon 3nm SII filter (50mm square) - £739.00

Select your Red Continuum filter 5nm Astrodon 5nm Red Continuum filter (1.25" mounted) - £203.00 Astrodon 5nm Red Continuum filter (50mm diameter) - £432.00 Astrodon 5nm Red Continuum filter (50mm square) - £499.00 3nm Astrodon 3nm Red Continuum filter (1.25" mounted) - £290.00 Astrodon 3nm Red Continuum filter (50mm diameter) - £639.00 Astrodon 3nm Red Continuum filter (50mm square) - £739.00

Near infrared filters

The NIR region remains largely unexplored by amateur imagers. Perhaps this is due to the impression that the Si CCD camera is not sufficiently sensitive in the NIR. Perhaps it is not clear what can be imaged in the NIR. Narrowband imaging has only recently become popular, allowing imagers to take images from backyard equipment like the Hubble Space Telescope's "Pillars of Creation" (Messier 16). NIR imaging may follow this recent narrowband evolution and become another tool in the imager's toolkit.

Select size / fitting Astrodon NIRL123 Tri-color Imaging - set of 4 (1.25" mounted) - £353.00 Astrodon NIR Luminance - >;700 nm (1.25" mounted) - £137.00 Astrodon NIRL123 Tri-color Imaging - set of 4 (50mm diameter) - £727.00 Astrodon NIR Luminance - >;700 nm (50mm diameter) - £215.00

Photometric filters

Astrodon-Schuler UVBRI photometric filters have become a popular, low-cost addition for astronomical photometric measurements. The American Association of Variable Star Observers (AAVSO) orders the Astrodon-Schuler V filter for its members. Many of the filters go to universities for research.

Select your 1.25" filter Astrodon UV filter (1.25" mounted) - £74.00 Astrodon Bu filter (1.25" mounted) - £74.00 Astrodon V filter (1.25" mounted) - £66.00 Astrodon Rs filter (1.25" mounted) - £66.00 Astrodon Is filter (1.25" mounted) - £66.00 Astrodon BVR filters (1.25" mounted) - £174.00 Astrodon BVRI filters (1.25" mounted) - £220.00 Astrodon UVBRI filter (1.25" mounted) - £270.00

Select your 48mm mounted filter Astrodon UV filter (48mm mounted) - £137.00 Astrodon Bu filter (48mm mounted) - £137.00 Astrodon V filter (48mm mounted) - £107.00 Astrodon Rs filter (48mm mounted) - £107.00 Astrodon Is filter (48mm mounted) - £107.00 Astrodon BVR filters (48mm mounted) - £313.00 Astrodon BVRI filters (48mm mounted) - £393.00 Astrodon UVBRI filter (48mm mounted) - £436.00

Select your 50mm square filter Astrodon UV filter (50mm square) - £148.00 Astrodon Bu filter (50mm square) - £148.00 Astrodon V filter (50mm square) - £118.00 Astrodon Rs filter (50mm square) - £118.00 Astrodon Is filter (50mm square) - £118.00 Astrodon BVR filters (50mm square) - £450.00 Astrodon BVRI filters (50mm square) - £417.00 Astrodon UVBRI filter (50mm square) - £553.00