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Shelyak Grating module for the Lhires III - 1200 l/mm

Shelyak Grating module for the Lhires III - 1200 l/mm

by Shelyak
SKU SHK-SE0006
CA$1,018.00 - CA$1,018.00
CA$1,018.00
CA$1,018.00 - CA$1,018.00
CA$1,018.00
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  • 1200 lines/mm Grating
  • Direct-Fit Module for Lhires III
  • Expands Spectrograph Wavelength Coverage
  • Ideal for Spectroscopic Surveys
  • Interchangeable with Standard Grating
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • Grating module for the Lhires III - 1200 l/mm

    Swap the standard 2400 l/mm grating in your Shelyak Lhires III spectrograph for this 1200 lines/mm module to trade high resolution for significantly broader spectral coverage in a single exposure. This module is an essential accessory for observers who need to characterize objects with unknown features or monitor phenomena across a wide spectral range, such as supernovae or comets.

    The 1200 l/mm Trade-Off: Broader Wavelength Coverage at Lower Resolution

    In spectroscopy, a grating's line density dictates the trade-off between spectral resolution and wavelength coverage. A higher line count, like the Lhires III's standard 2400 l/mm grating, spreads the light out more, delivering higher resolution over a smaller spectral window. This 1200 l/mm grating does the opposite; with fewer lines, it produces a less dispersed spectrum, allowing a much wider range of wavelengths to fall onto your sensor in a single frame.

    This capability is critical for survey work, initial classification of variable stars, or capturing the full profile of objects with broad emission lines. Instead of taking multiple exposures to piece together a spectrum, you can capture the entire visible range at once, saving valuable observing time.

    1200 l/mm vs. 2400 l/mm: Choosing the Right Grating for Your Target

    The standard 2400 l/mm grating is the correct tool for the high-resolution work the Lhires III is famous for—measuring precise radial velocities, studying detailed line profiles of Be stars, or resolving close binary systems spectroscopically. It prioritizes detail over breadth.

    The 1200 l/mm grating module excels when the scientific goal is characterization rather than fine measurement. It is the superior choice for:

    • Supernova and Nova Spectroscopy: Capturing the evolution of multiple, broad spectral features (like Silicon II or Hydrogen lines) simultaneously as the object brightens and fades.
    • Quasar and AGN Characterization: Identifying highly redshifted emission lines across a wide spectral range to determine the object's distance and nature.
    • Cometary Analysis: Observing molecular emission bands from species like C2 (Swan bands) which span a significant portion of the visible spectrum.

  • Why would I choose the 1200 l/mm grating for my Lhires III over the standard 2400 l/mm?

    You would choose the 1200 l/mm grating when your primary goal is to capture the widest possible range of wavelengths in a single exposure. The standard 2400 l/mm grating provides higher resolution but covers a much narrower spectral window. The 1200 l/mm module is for survey work and broad characterization, not fine detail analysis.

    What is the main advantage of a lower-resolution grating like this 1200 l/mm module for the Lhires III?

    The main advantage is efficiency. For objects like supernovae, comets, or quasars, important spectral features can be spread far apart. The 1200 l/mm grating allows you to capture all of them in one shot, saving time and simplifying data acquisition compared to creating a mosaic of multiple high-resolution exposures.

    Is the 1200 l/mm grating module difficult to install in the Lhires III?

    No, the Lhires III is designed for interchangeable grating modules. The process involves opening the access panel and carefully swapping the existing module with the new one. Always refer to your Lhires III manual for the specific procedure to avoid damaging the delicate grating surface.

    If I want to study the H-alpha line profile of Vega (Alpha Lyrae) with my Lhires III, is the 1200 l/mm grating the right choice?

    No. For detailed analysis of a single, narrow spectral line like H-alpha, the standard 2400 l/mm grating is the correct tool. Its higher resolution is necessary to reveal subtle shifts and profile changes. The 1200 l/mm grating would show the line, but without the detail needed for scientific measurement of its profile.

    I'm using my Lhires III on an 8" SCT to monitor a supernova. Why is the 1200 l/mm grating module a good tool for this?

    Supernovae exhibit broad, evolving spectral features across the entire visible spectrum. The 1200 l/mm grating's wide spectral coverage is ideal for this task, as it allows you to capture the appearance and evolution of key features like the Silicon II (Si II) absorption line in Type Ia supernovae and the broad Hydrogen lines in Type II, all within a single frame.

    Does using the 1200 l/mm grating module change the calibration process for the Lhires III?

    Yes, absolutely. You must perform a new spectral calibration after installing the 1200 l/mm grating. The dispersion (angstroms per pixel) is different from the 2400 l/mm grating, so your previous calibration files will no longer be accurate. You will need to create and save a new calibration profile for this specific setup.

  • Grating Density 1200 lines/mm
    Compatibility Shelyak Lhires III Spectrograph
    Application Low Resolution, Wide Field Spectroscopy

    • 1200 l/mm Grating Module for Lhires III

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  • Shelyak 1-Year Warranty