Optec - Astrodon Rc photometric filter, 50mm diameter, 3mm thick.
Astrodon Photometrics UVBRcIc filters adhere to the Johnson/Cousins designs as closely as possible. The following is a spectral compilation of actual scans of the Astrodon Photometrics UVBRcIc filters.
These filters are parfocal with all Astrodon LRGB and narrowband filters. You can add an Astrodon Clear or H-a filter and they will be parfocal within the limits of your optical system.
- Curves designed after UV, B, V, Rc, Ic Johnson/Cousins
- 100% coated filters - no colored glass
- Peak transmission guaranteed > 90%
- <0.1%Tave out-of-band 300 - 1100 nm
- Striae-free, single fused silica substrates
- 1/4-wave propagated wavefront prior to coating
- <0.5 arcminute substrate parallelism
- 3.000 +/-0.025 mm substrate thickness
- 1.25" mounted
- 49.7 mm dia. unmounted (for most filter wheels)
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.