Lunt Solar System H-alpha telescope:
This complete solar telescope is a high-quality achromat, with the front lens reducing stray light to half that of a standard achromatic objective. This eliminates possible coma, astigmatism, centering deviations and, together with the appropriate collimation lenses, makes a spherically-corrected flat-field solar telescope. The image is optimized for maximum sharpness in the red part of the spectrum. The optical system is shadow-free (no central obstruction) and is suitable for observing the Sun's surface, as well as for prominences. The tube is made of metal and has been painted white.
Filtering is via an Etalon system: 2 parallel plates made of transparent material, e.g. silica glass with a mirrored surface. Such a system has frequency-dependent, periodic transmission maxima and loss minima. The Etalon filter used by the Lunt Solar System telescope isolates a specific wavelength of the solar spectrum: the H-alpha line. The internal Etalon system with fine tuning allows observing over a better than 0.7 Angstrom bandwidth. With an additional double-stack Etalon filter, which can be mounted in front of the front lens of the telescope, a bandwith of less than 0.5 angstrom is achieved.
The sensitive and precise focusing is done by a high quality 2" Crayford Focuser with 1:10 reduction. So you have a visual as well as photographically full control and always a sharp picture, what is essential particular at the solar observation.
The solar telescopes of the LS35T series will be delivered according to the package with a variant of the following block filter (see delivery): B400 (4mm) or B600 (6mm). Please note that the operation without block filter is not possible and is extremely dangerous!
Properties of the optics:
- Opening: 35mm
- Focal length: 400mm
- Half width with an internal etalon filter: <0.75 Angstroms
Delivery of optics:
Our expert comment:
At Lunt telescopes, there are a number of variants with different options. It is possible to find out which model is being offered by looking at the designation.
An important criterion, also reflected in the price, is the size of the blocking filter. There are 3 different blocking filter sizes: 6mm, 12mm and 18mm in diameter. The designations for these are B600, B1200 and B1800 respectively. If there is nothing in the title, then it is an OTA without a blocking filter!
CaK or Ha mean that the instrument has been optimized for the blue calcium line or the red H-alpha line. Over 90% of instruments sold are H-alpha instruments, with the designation Ha.
C or FT refer to the two different focuser versions. C means the standard focuser and FT means an improved model from FeatherTouch.
PT is the designation for instruments with fine tuning that uses air pressure. Non-PT filters have fine tuning that works by tilting. The air pressure version usually provides a somewhat more homogeneous field.
DS or DS50 is the term for a 'double stack'. These instruments have two Etalon filters. This achieves a tighter bandwidth and therefore better contrast.
In addition, you can find 2 numbers in the title separated by a slash. The first number indicates the diameter of the front lens. The second number is the focal length. So a 60/500 telescope would have a 60mm aperture and a focal length of 500mm. The lens diameter is usually also the diameter of the Etalon supplied.
