ToupTek PureSight A1 2-inch 5NM F/3.2 Dual Narrowband Filters Ha+OIII Astronomical Filter for Deepsky Photography

Description:
- Specially designed for color astronomical photography in high light hazardous environments.

- 5nm ultra narrow full width at half maximum (FWHM), accurately passing through the Hα (656.3nm) and OII (500.7nm) core emission lines, penetrating the photodamage barrier.
- Cut off depth of average OD5+, transmittance 0.001%; Effectively blocking 99.999% of non target spectral areas, effectively filtering out urban light pollution interference such as streetlights and neon lights.

- The high-purity fused silica substrate and IAD ion assisted deposition coating process make the film compact and even, leaving the halo ghost behind.

- The anti reflective film layer significantly reduces internal reflection and suppresses halo. The imaging background is pure and the star points are sharp.

- 90%+ high transmittance, ≤30" high parallelism, 60/40 surface finish; balanced light control and transparency, clear presentation of nebula shadows and details. City balconies can also shoot pure deep space image quality.

- Aluminum alloy matte black filter frame, solid and wear-resistant, effectively reduces stray light reflection.

- For deep optimization of fast optical systems with F/3.2 and above, stable performance can still be achieved at F/2.8.

- 2-inch size suitable for full frame and below color cameras. M48x0.75 standard thread easily connects to 2-inch 7-hole or 5-hole filter wheels and 2-inch filter drawers.

Specification:
- Target spectral lines: Ha 656.3nm & OIII 500.7nm
- FWHM (full width at half maximum): 5.0nm±1.2/5.0nm±1
- Peak transmittance: >90%
- Cut off depth: better than average OD5 at 200-1100nm
- Base material type: fused silica
- Thickness: 2.00mm±0.1
- Parallelism: ≤30”
- Surface smoothness: 60/40
- Adaptive optical system: ≥F/3.2
- Coating process: IAD ion assisted deposition technology
- Size: 2 inches (with filter frame, frame height 5mm, thread height 2mm)
- Filter installation thread: M48 x 0.75
- Filter frame material: aluminum alloy
- Effective aperture: 43.9mm
- Installation direction: thread side facing sensor

Package Included:
- 1 x Dual Narrowband Filter