Artesky ERF Filter 100mm with Metal Cell Ø146mm
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 moduloThe Artesky ERF 100mm filter is an infrared pre-filter already mounted in an aluminum cell (Ø146mm), ready to use in front of the telescope objective: essential for H-alpha solar observation with Daystar or Solar Spectrum filters.
What the ERF is for
An ERF (Energy Rejection Filter) reflects most of the solar energy before it enters the optical tube, preventing overheating of the H-alpha etalon and the telescope optics. Unlike bare glass, the Artesky version with cell is ready to mount, with no need for 3D-printed or custom cells.
Homogeneous high-transparency glass
The glass substrate is not the traditional coloured absorptive type, but highly transparent and homogeneous, polished to objective-lens quality, with a high-performance reflective coating on one side.
Exclusive dielectric coating
The Artesky coating reflects the unwanted spectrum from 200 to 1100nm, letting through only a 60nm window centred on H-alpha (656.28nm), with 95% peak transmittance and OD4 blocking depth.
Technical specifications
| Glass diameter | 100 mm |
| Glass thickness | 12 mm |
| Surface flatness | λ/4 |
| Centre wavelength | 656.28 nm |
| Bandwidth (FWHM) | 60 nm |
| Peak transmittance | 95% |
| Blocking range | 200-1100 nm (OD4) |
| Cell | Aluminum 6061, internal Ø146mm / external Ø154mm |
| Supplied as | Glass already mounted in cell |
Frequently asked questions
Does the ERF replace the H-alpha filter? No, it's a pre-filter: it must always be used together with an H-alpha filter (Daystar or Solar Spectrum), never alone.
Is it ready to mount? Yes, unlike filters sold as glass only, this version already includes the aluminium cell.
⚠️ Safety warning
The ERF filter must always be mounted in front of the telescope aperture, with the coated side facing the Sun, and used exclusively together with an H-alpha filter. Improper use in direct visual observation can cause severe, permanent eye damage.