The most accessible way to see the sun in H-alpha
The Lunt LS40THa with B500 blocking filter is a complete solar telescope: you don't need anything else but a camera tripod. Where with a regular telescope and solar filter you only see sunspots, H-alpha reveals a completely different sun. Prominences curling off the edge like flames, dark filaments across the surface, and active regions that change from day to day.
A real Lunt at an entry-level price
The LS40THa uses the same filter technology as the larger Lunt models: an etalon with a bandwidth of less than 0.7 Ångström, tuned with mechanical tilt-tuning. This allows you to precisely align the transmission with the H-alpha line and extract contrast from prominences and surface detail. The 40 mm unobstructed aperture provides a sharp image of the entire solar disk in a handy size of only 1.2 kg.
B500-blockfilter: made for visual perception
The B500 block filter is housed in the zenith mirror housing with a 1.25-inch connection and has 5 mm free aperture. For visual observation with a 400 mm focal length, this is more than sufficient: the entire solar disk fits comfortably in the field of view. If you primarily want to photograph with a camera, consider the B1200 version with a 12 mm aperture.
Setup and observation
The tripod thread allows you to mount the LS40THa on a camera tripod or a lightweight astronomy mount. The included Sol-Searcher projects a sun image onto a small screen, so you can safely find the sun without looking through a finder. Focusing is done with the helical focuser. Within minutes, you'll be pointed at the sun.
In the box
- LS40THa solar telescope
- B500 block filter in zenith mirror housing
- Sol-Searcher
- Prismarail (GP)
- Manual
Specifications
| Feature | Value |
|---|---|
| Optics | 2-lens refractor, no obstruction |
| Opening | 40 mm |
| Focal length | 400 mm (f/10) |
| Bandwidth | less than 0.7 Angstroms |
| Alignment | Mechanical tilt tuning |
| Blockfilter | B500 (5 mm clearance), 1.25 inch |
| Focuser | Helical |
| Ocula Connection | 1.25 inches (31.7 mm) |
| Angle resolution | 3.45 arcseconds |
| Weight | 2.65 lbs |
An H-alpha solar telescope is safe for solar observation due to its closed filter system. Check the etalon and blocking filter for damage before each use. Never look at the sun through an ordinary telescope, binoculars, or finder without a certified solar filter on the objective end.
Are you undecided between white light and H-alpha, or between the Lunt models themselves? View all solar telescopes side by side or the full range on the Lunt Solar Systems merk Page.







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