ANTLIA F2 SHO 0.5mm Ultra-thin Highspeed Filter Set FWHM 6nm H-alpha+SII+OIII Astronomical Filters (2-Inch)

Why choose FWHM 6nm?
- Narrowband filters will produce wavelength shift with the angle of incident light, which is a physical characteristic. In high speed telescopes like F2, if the bandwidth is too narrow, it will shift out of band and lose information; If the bandwidth is too wide, it will reduce the contrast of the image. 6nm was proposed through simulation and long-term coating experience, which requires very precise wavelength control to ensure that good signals can still be obtained in the high speed system of F2.

Why does the F2 telescope need to use a 0.5mm ultra-thin filter?
- F2 belongs to ultra high speed telescopes, such as RC and Newtonian reflectors. These telescopes have a fast focal ratio, a large field of view, and are sensitive to aberrations. If a conventional 2-3mm thick filter is used, the edge rays will be excessively refracted, causing the focal plane to become curved, resulting in a circular central star point. The edge star points are elliptical.

Advantages of 0.5mm ultra-thin filter:
1. The thickness is reduced, and the optical path difference (OPD) is sharply reduced, greatly correcting the field curvature and keeping the focal plane flat from the center to the edges of the entire image.
2. A thickness of 0.5mm can reduce the impact of coma and minimize the deformation of star points.
3. Small heat capacity. It can quickly achieve thermal equilibrium and reduce airflow disturbance caused by lens temperature difference in the early stages of shooting.

Specifications:
- FHWM: 6nm
- Base plate thickness: 0.5mm
- F2 high speed design
- Flat-top spectrum
- T>95%
- OD5 at 300-1180nm

Package Included:
- 1 x SHO Filter Set