Discover the prominences and details of the chromosphere with two switchable H-alpha filters in the same Gemini Combo. For compatible SCTs, Maksutovs, and refractors: no built-in Barlow lens; working focal ratio and ERF must be verified for your mount.
CHF 2'380.00incl. Swiss VAT
Will be ordered for you
Timeframe: 10 days to 3 weeks
Estimated shipping: Between November 25 and 30, 2026
The Gemini Combo combines H-alpha filters Prominence and Chromosphere for instant switching via a side-mounted slider. Enjoy the best of both bandwidth options in a single tool, without hardware swapping or refocusing.
The Gemini Combo allows :
Important: for SCT and Maksutov, a front-mount energy rejection filter (ERF) is mandatory to protect the optical tube and obtain optimum performance.
The Gemini Combo allows you to use a compatible SCT, Maksutov, or refractor to view the Sun in two different H-alpha images. Its two switchable filters are particularly useful for quickly comparing prominences and chromospheric details during an animation or photo session.
This Combo version does not include a built-in Barlow lens: the working focal ratio, any telecentric option, and the energy-rejection filter must be selected together. Check the DayStar Official Compatibility Checker and Gemini Combo Instructions. For a fast refractor, also compare the Gemini with built-in telecentric lens.
Visit DayStar Solar Accessories allow you to adapt the connection to the eyepiece or camera: 1.25-inch or 2-inch connectors, T- or C-mounts, and adapters, depending on the model. Thread compatibility, focus extension, and focus must be checked for each combination. Accessories are sold separately.
In astrophotography, a DayStar tilt adapter can help reduce Newton's rings. The results depend on the camera and the settings; see the Manufacturer's installation instructions to choose the right adapter.
DayStar has been developing solar equipment for over 50 years. Whether for an introductory course, an educational activity, or an imaging program, Contact Deep Space Astronomy Please provide the model of your instrument, your camera (if applicable), and your lenses: we'll help you choose a suitable setup and provide a quote.
| Type | Gemini H-alpha Combo filter (Prominence + Chromosphere) |
|---|---|
| Compatibility | SCT, Maksutov, F/15-F/30 refractors |
| Eyepiece outlet | Standard 1.25″, 1.25″ snout included + 2° off-axis adapter for ERF |
| Barlow / Optics | No integrated Barlow - 0 power, filter only. Optional telecentric barrows available. |
| Blocking filter | Integrated, 25 mm |
| Clear aperture | 21 mm |
| Power supply | USB 5 V 1.5 A, incl. 90-240 V mains adapter |
| Tuning | Wheels for wing shift ±0.5 Å with notches every 0.1 Å; LED status: power, warming, ready, fault |
| Warranty | 5 years |
| Supplied box | Hard case for protection and transport |
| Observation | Full disk up to ~1800 mm focal length; no aperture limitation, use with SCT and Maks off-axis ERF |
| Optional accessories | 8h battery pack |
| Criteria | Prominence | Chromosphere |
|---|---|---|
| Bandwidth FWHM | Wider — brighter | Narrower — better surface contrast |
| Filaments | Difficult to observe | Visible and detailed |
| Protuberances | Very shiny blade | Visible but less brilliant |
| Contrast | Less contrast, brightness priority | High contrast, ideal for chromospheric detail |
| Recommended use | Quick visual observation | Detailed observation and astrophotography |
