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IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
Shelyak Grating module for the Lhires III - 150 l/mm

Shelyak Grating module for the Lhires III - 150 l/mm

by Shelyak
SKU SHK-SE0009
$738.00 - $738.00
$738.00
$738.00 - $738.00
$738.00
Price Match Policy!
  • 150 lines/mm Grating
  • Low Resolution / Wide Spectral Range
  • Designed for the Shelyak Lhires III Spectroscope
  • Enables Faint Object Spectroscopy
  • User-Interchangeable Module
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  • Description
  • FAQ
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  • Warranty

  • Grating module for the Lhires III - 150 l/mm

    This 150 lines/mm grating module transforms the Shelyak Lhires III from a specialized high-resolution instrument into a versatile survey spectroscope. By replacing the standard 2400 l/mm grating, you dramatically lower the dispersion to capture a much wider spectral range in a single exposure, opening up new targets for scientific analysis.

    Survey Mode for the Lhires III: The 150 l/mm Advantage

    The core purpose of the Lhires III is high-resolution spectroscopy, but this requires bright targets and isolates a very narrow slice of the spectrum. The 150 l/mm grating module intentionally trades that high resolution for a massive increase in spectral bandwidth and throughput, allowing you to analyze faint, extended, or continuum-source objects that are inaccessible with the standard grating.

    This makes the 150 l/mm module the ideal tool for rapid classification of transient events like supernovae and novae, studying the broad emission features of comets, or capturing the full visible spectrum of faint deep-sky objects. It effectively adds a "survey mode" to your Lhires III, expanding its research capabilities significantly.

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

    Selecting the correct grating is critical for matching the instrument to your scientific goals. The two options serve fundamentally different purposes.

    • Standard 2400 l/mm Grating: This is for high-resolution work on bright stars. Use it to detect the subtle Doppler shifts in binary star systems, analyze the fine absorption lines in a stellar atmosphere (like the Sodium D-lines), or measure precise radial velocities. Its spectral range is very narrow.
    • 150 l/mm Grating Module: This is for low-resolution "big picture" spectroscopy. Use it to obtain a spectrum of a faint comet, classify a supernova by its broad spectral features, or monitor the spectral evolution of a variable star across the entire visible range at once.

  • What is the main application for the Shelyak 150 l/mm grating module for the Lhires III?

    The primary application is for low-resolution spectroscopy of faint or transient objects. It allows you to capture a wide spectral range in a single shot, which is essential for classifying objects like supernovae, analyzing the broad emission bands of comets, or studying faint nebulae.

    How does the 150 l/mm grating change the data I can collect with my Lhires III?

    It fundamentally changes the trade-off between spectral resolution and wavelength coverage. Instead of a very detailed view of a tiny part of the spectrum (like with the standard 2400 l/mm grating), the 150 l/mm grating provides a lower-detail view of a much wider portion of the spectrum. This is better for understanding the overall nature of an object rather than its fine atmospheric details.

    Do I need to recalibrate my Lhires III when I switch to the 150 l/mm grating?

    Yes, absolutely. Any time you change the grating in a spectroscope, you must perform a new wavelength calibration. The dispersion, or how much the light is spread out per pixel, is completely different for the 150 l/mm grating compared to the standard 2400 l/mm grating. You will need to take new calibration frames with a reference lamp.

    Is the 150 l/mm grating suitable for classifying a newly discovered supernova like SN 2023ixf with an 11" SCT?

    Yes, this is an ideal use case. An 11" SCT provides enough light-gathering power, and the 150 l/mm grating provides the wide spectral coverage needed to identify the characteristic broad absorption lines (like Silicon II for a Type Ia) used for supernova classification. The standard 2400 l/mm grating would be unsuitable for this task as it would only show a tiny, unidentifiable fraction of the spectrum.

    Can I use the 150 l/mm grating to study the changing tail composition of Comet C/2022 E3 (ZTF)?

    This is another excellent application. Cometary spectra are dominated by broad emission bands from molecules like C2 (the Swan bands) and CN. The 150 l/mm grating allows you to capture all these features simultaneously to monitor how the comet's outgassing and composition evolve as it approaches and leaves the sun.

    When should I use the standard 2400 l/mm grating instead of this 150 l/mm module?

    You should use the standard 2400 l/mm grating when your scientific goal requires very high spectral resolution for bright targets. This includes measuring precise radial velocity shifts from stellar wobble, studying the detailed profiles of spectral lines in Be stars, or resolving close spectroscopic binaries.

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