Shelyak LISA Pack Spectrograph
LISA is a high luminosity slit-based spectrograph (F/5), designed to observe faint or extended targets. It is mounted directly at prime focus of the telescope and includes a guiding feature. In one exposure, it covers the full visible domain (400 to 700 nm).
Spectrography through the LISA
Most spectrographs are based on the same principle: a light source (slit) is collimated by a collimator lens, then spread out by an optical element (prism or grating), and refocused with an objective lens on a sensor (Camera CCD chip for instance) to form the spectrum.
Of course, the smaller the source is, the finest will be the spectrum: to get enough resolution, we must have a source small enough. In astronomy, source is - usually - a star, but that doesn't necessarily mean it is small enough for our purposes. Even if the actual source of light is very small, its image is enlarged by the atmosphere and the telescope. The bigger the telescope, the bigger will be the star image (in fact, image size depends on two parameters: the telescope focal length and the seeing of the sky).
To control the source size, there is a slit at the entrance of the LISA spectrograph. This slit delivers the object size for the spectrograph. Then, the spectrograph disperses the light source - going through the slit - into a spectrum. The resolution of the spectra is given by the slit width and internal optics. You simply have to adapt and tune the telescope in order to get the maximum light in the slit.
Spectroscopy is used in many applications, but spectroscopy applied to astronomy has some specific special features:
- The light source is usually faint: you must have an efficient optical system to take advantage of each photon.
- To get light from the source, you must use a telescope, which is moving at Earth's speed.
The LISA Pack, mounted on the telescope, is compact and rigid, to make a stable spectrum over time. It also offers a guiding system in your LISA: a guiding camera looks at your telescope's field of view to help you guide - or even auto guide - your telescope.
LISA Pack Specifications
- Power of Resolution: R aprox. 600 to 1000
- Visible Range: (400 to 700 nm)
- Collimator: F=130 mm F/5
- Custom Lens: F=88 mm F/2.4
- Slit 15/19/23/35-microns
- Weight: 2.5 kg (1.4 kg spectrograph alone)
- Telescope Interface: M42 x 0.75 mm thread
- Backfocus: 41 mm
- Calibration Module: (Neon and Tungsten Lamps)
- Atik 314L+ Acquisition Camera: (1392 x 1040 x 6.45 microns)
- Atik Titan Guiding Camera: (659 x 494 x 7.4 microns)
- 12V 7A Power Supply with Four Way Cable
- Carry Case with Custom Foam