Antlia H-Alpha 3.5nm Filter 50mm
When will I receive it?
Products marked In stock are dispatched promptly — the exact delivery estimate for your address is shown at checkout, before you confirm the order.
For international shipments, delivery times depend on the destination and are always displayed at checkout before payment.
Products marked Available on order require 5–15 business days for processing. Our team will keep you updated promptly if anything changes.
What are the warranty terms?
Shop with confidence: all our products include a 24-month legal warranty for conformity defects, managed directly by our team.
Many brands also offer extended warranty coverage beyond 24 months — contact us to find out the specific terms for the product you're interested in.
Click here for more information.
Can I return a product?
Yes: you have 14 days from delivery to return any product and receive a full refund — see our Refund Policy for full details.
Items must be returned in their original condition and packaging. Return shipping costs are the customer's responsibility.
Not sure which product is right for you? Contact us before buying — we'll help you find the perfect instrument so you won't need to return anything.
Sei un'azienda? Compila il modulo per la fatturazione
Clicca sul pulsante qui sotto per inserire i tuoi dati aziendali:
Vai al moduloAntlia H-Alpha 3.5nm Filter 50mm – Ultra-Narrow Band for Astrophotography
The Antlia H-Alpha 3.5nm filter is an ultra-narrow band filter centered on the ionized hydrogen emission line at 656.3nm, with a bandwidth of just 3.5nm. It guarantees transmission above 88% on the H-Alpha line and out-of-band blocking of OD3 (0.1%) from 300 to 1100nm, for maximum contrast even under heavy light pollution and during moonlit nights.
Designed specifically for new-generation CMOS cameras and fast telescopes down to f/2.0, the filter uses a monolithic, non-glued Schott substrate with double-sided polishing and multi-layer nano-coating. The unmounted 50mm format, with increased thickness for flatness over larger surfaces, is designed for large-format filter wheels, with hand-blackened edges to eliminate stray light.
The H-Alpha component of the SHO set (H-Alpha + OIII + SII), it enables high-contrast imaging of emission nebulae, supernova remnants and planetary nebulae on large-format sensors.
Key Features
- 3.5nm bandpass – maximum contrast and light pollution suppression
- Transmission >88% on the H-Alpha line at 656.3nm
- OD3 (0.1%) blocking from 300 to 1100nm
- Monolithic, non-glued Schott substrate, hand-blackened edges
- 50mm unmounted format, increased 3mm thickness
- Compatible down to f/2.0
Technical Specifications
| Filter type | Ultra-narrow band H-Alpha |
| Center wavelength | 656.3nm |
| Bandpass (FWHM) | 3.5nm |
| H-Alpha transmission | >88% |
| Out-of-band blocking | OD3 (0.1%) @ 300–1100nm |
| Format | 50mm (unmounted) |
| Substrate | Schott, 3mm ±0.05mm thickness |
| Surface quality | 60/40 (MIL-O-13830) |
| Flatness | 1/4λ |
| Parallelism | 30" |
| Coating | Multi-layer nano-coating, double-sided |
| Focal ratio | Down to f/2.0 |
| Recommended use | Mono CCD/CMOS, SHO imaging, large-format filter wheels |