For the complete eShell II solution, see SHE-ES0006

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   Shelyak - Full eShel II System

   $21,412.80

   SKU: SHE-ES0006

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• The Shelyak eShel II Spectroscope design is a collaboration between Shelyak, Christian Bui, and Michel Pujol.
• The eShel II is an Echelle Spectrograph known for its flawless accuracy and performance.
• Echelle spectrographs disperse parallel light beams using a special grating and focus the dispersed light onto a detector.
• Czerny-Turner spectrographs use collimating mirrors and are preferred for broader wavelength ranges, while Echelle spectographs excel at higher resolution within a shorter wavelength range.
• Echelle spectographs are superior for observing stars and other activities where most of the emission lines and bandpass are focused in one area of the spectrum.
• The eShel II can measure wavelengths between 450 to 700nm with a resolution of >10,000.
• Shelyak has developed the eShel software, an open-source program that controls the various components of the eShel II for spectral line measurement and analysis.
• Spectral recording can be stored and exported using a multi HDU fits file format.

The Shelyak eShel II Spectroscope design is a joint collaboration between Shelyak, Christian Bui, a renowned optic specialist and Michel Pujol who designs Tcl/Tk and AudeLA software applications. These factors combined together make an outstanding Echelle Spectograph design with absolutely flawless accuracy and performance.

Since the eShel II is based on the framework of Echelle spectrographs, it is beneficial to nail down the differences and advantages when compared to other spectrograph models like Czerny-Turner. While the end goals of each are give or take, the same, the way they disperse light and measure it is somewhat different.

• Unlike Czerny-Turner spectrographs which use collimating mirrors to create parallel light beams that can furthermore be dispersed and focused on a mirror, Echelle spectographs use a different type of grating to disperse these parallel light beams which can render better accuracy. A camera lens focuses the dispersed light onto a detector like a camera sensor.
• Compared to Czerny-Turner which generally are preferred for broader wavelength ranges (for instances, measuring Near IR to visible), Echelle versions instead excel at higher resolution of spectral lines and measurements within a somewhat shorter wavelength range making them far superior for observing stars or other activity whereas most of the emission lines and bandpass are focused in one area of the spectrum. This also prevents less instances of overlapping of spectral lines which could cause inaccurate data at longer wavelengths. In the case of eShell II, spectral gratings are >20.

Using the main eShel II, anything between 450 to 700nm can be measured with an >10,000 resolution (measured with an ATIK 460). The spectral domain is also now extended 30-55.

Shelyak eShell II used in conjuction with an 8" SCT, Canon 40D at 9 x 300 s showing the H-Alpha line emphasized in emission near the mid top right.

Shelyak has developed the eShel software which is an open source based program that can control the various components of the eShell II such as the calibration and injection to measure and analyze spectral lines. Following this, with a multi HDU fits file, spectral recording can be stored and exported.

Calibrated recorded spectral analysis of Beta Persei between H-Beta and H-Alpha using the eShel software.

• Fiber injection and guiding unit
• Calibration unit
• Echelle spectroscope
• eShel Software

Beta Lyr – Shelyak [:-)] & P Cygni – 7 x 300 s 8′ SCT

WR 140 and Nova Del 2013 1x600s 14′ SCT and ATIK 460EX bin 2×2

Here is also a good exemple of echelle spectroscopy with an animation of raw images of BW Vul, a pulsating star. 5min expoures, 60cm f/3.5 telescope at pic du Midi; QSI 516s camera.

Here is a spectrogram of BW Vul around Sodium doublet.