Astronomical Spectroscopy - The final frontier - to boldly go where few amateurs have gone before!
Now you can examine the structures of stars, their temperatures and chemical make-up, use the Doppler shift to measure close binary systems and the Redshift of distant Quasars, monitor variable stars and Supernovae as well as contribute to ProAm projects like the Be star database. All this can be achieved by using a good slit spectroscope on a medium sized telescope.
The Spectra-L200 meets all these needs. Originally designed as an intermediate resolution spectroscope kit for amateurs it has grown and developed into a very capable instrument. It can meet the needs of the first time novice as well as providing high resolution spectra for detailed analysis.
The Spectra-L200 is based on the Littrow design, is well proven and gives excellent performance. The optics used throughout are of the highest quality and are mounted in a robust precision Laser cut/ CNC machined housing. The weight is not much more than some CCD cameras. It can be used with any telescope with an f ratio of f/7 or greater with no loss of efficiency. The entrance port is a female T thread. Any suitable adaptor can be fitted to match your current focuser.
A specially designed custom made multi-reflective entrance slit plate provides a unique arrangement of nine different slit gaps (20/25/30/35/40/45/50/75/100 micron) and three pinholes (20/50/100 micron). These can quickly be set using a built-in thumbwheel. The highly reflective chromium surface allows the target star to be imaged in a guide camera. The transfer mirror and optics present a large field of view to any standard guide camera (1.25" fitting) - ATiK16, Lodestar etc. This makes it very easy to confirm the correct star is located on the entrance slit and any star image visible can be used for guiding.
The heart of the instrument is the reflective grating. This is positioned in the collimated, parallel beam behind a fully coated over sized achromatic doublet. A quick change over grating module has been developed to allow various gratings from lo-res to hi-res to be swapped over easily and safely. This provides great versatility, and allows the user to choose the best resolution for the data required. 150/300/600/1200/1800 l/mm grating assemblies are available. The gratings used are maximum thickness and over sized to ensure stability. All are blazed to provide maximum efficiency.
The gratings need to be able to rotate, to bring the required central wavelength to the imaging camera field of view. To ensure maximum accuracy and smooth control, the grating is mounted in a holder supported in a precision aerospace ball bearing and tensioned by a circumferential spring. Each grating assembly is tested and aligned prior to despatch. A micrometer head fitted with a custom nosepiece provides repeatable positioning of the grating.
The imaging port of the Spectra-L200 is fitted with a female T thread adaptor. This allows any of the standard camera adaptors and focusers to be fitted. The design back focus distance allows all DSLR and CCD cameras to be used.
Specifications summary:
- Littrow Type
- Connector: T2 Female
- Construction - Laser cut and folded aluminium sheet metal
- Weight: 1.2 Kg. The inside of the housing is 60mm x 60mm
- Backfocus: 60mm (Enough for DSLR camera)
- Slit: Reflective slit, multi slit (indexing)
- Optimised: f/7 (300/600/1200 l/mm) & f10 (1800 l/mm)
- Collimator: 38mm clear aperture achromatic doublet, f/l 200mm
- Standard grating: 600l/mm (30 x 30mm), optometric blazed
- Standard resolution: R=3000 (9um pixels)
- Options: Reference lamp assembly, additional grating assemblies, carry/storage cases, custom engraving, telescope/camera adaptors
The Spectra-L200 comes in a standard and a DEluxe version. Here's the difference:
Grating: Reflective grating, 30mm sq. x 9.5mm thick, blazed for 500nm. Available in 150/300/600/1200 and 1800 l/mm.
- The Spectra-L200 comes with the 600l/mm
- The Spectra-L200 Deluxe comes with 3 gratings of choice. Please let us know, which three gratings you want!
The Spectra-L200 Deluxe comes with a Neon reference lamp assembly and a hard case (Deluxe-Version only).
