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Star’Ex 14-20-26-32 µm slit + 25 µm hole (GEN2)
The Star’Ex GEN2 4-position reflective slit provides four distinct slit widths—14 µm, 20 µm, 26 µm, and 32 µm—engraved on a 16mm square substrate using high-precision photolithography. A central 25 µm pinhole acts as an artificial star for easy setup, and the entire 2mm thick component is made from robust fused silica for extended spectral transparency down to 375 nanometers. Each 4mm long slit is widened by a factor of 10 at its end to facilitate advanced spectrophotometric calibration.
Four Slit Options from 14 µm to 32 µm for Versatile Spectroscopy
This second-generation slit offers four distinct apertures arranged in a square, allowing you to match the spectrograph's resolution to your target and seeing conditions. The narrow 14 µm slit is ideal for achieving very high spectral resolution on bright targets with a small telescope. In contrast, the wider 32 µm slit is better suited for low-resolution work or capturing faint signal with larger instruments, such as a 300 mm telescope, where maximizing light input is critical.
2mm Fused Silica Construction with UV Transparency
The substrate is a 2mm thick, 16mm square blade of fused silica (synthetic quartz), chosen for its exceptional durability and broad spectral transmission. This material is transparent deep into the ultraviolet, offering a modest but useful gain around 375 nanometers even with the standard Star'Ex optics. The 2mm thickness makes the slit robust against mishandling and allows both sides to be cleaned easily with a dampened cotton swab.
Integrated 25 µm Pinhole: An Artificial Star for Easy Benchtop Setup
A major innovation of the GEN2 design is the central 25 µm diameter hole. This pinhole acts as a perfect artificial star, allowing you to fully align and focus your spectrograph on a workbench without needing a telescope or a clear night sky. This feature dramatically simplifies the initial setup and calibration process, ensuring your instrument is perfectly configured before you attach it to the telescope.
4mm Length and Widened Ends for Advanced Spectrophotometry
Each slit is 4mm long, enabling you to capture spectra from extended objects like nebulae or comets. Furthermore, the final 0.5mm of each slit is widened by a factor of 10. This unique design provides critical data on atmospheric turbulence and instrument performance, and it is essential for acquiring the spectrophotometric data needed to calibrate your spectra in absolute flux values.
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What are the different slit widths on the Star’Ex GEN2 slit for?
The four widths allow you to optimize your spectrograph for different goals.
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14 µm & 20 µm: Best for high-resolution spectroscopy on bright stars where fine spectral detail is the priority.
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26 µm & 32 µm: Ideal for lower-resolution work on fainter objects or with larger telescopes, as they allow more light to enter the spectrograph.
What is the purpose of the 25 µm central hole on the Star'Ex GEN2 slit?
The 25 µm central hole serves as an artificial star. It allows you to perform a complete optical setup and alignment of your spectrograph on a workbench with a simple light source, without needing to attach it to a telescope. This makes initial configuration significantly easier and more precise.
How would I choose between the 14 µm and 32 µm slits for a 300 mm telescope?
For a 300 mm telescope, the 32 µm slit is generally the better choice. Its wider aperture is better matched to the typical seeing conditions and image scale of a larger instrument, allowing more light from your target to pass into the spectrograph. The 14 µm slit would be extremely difficult to use under average seeing and would discard most of the starlight.
What is the Star'Ex GEN2 slit made of and why does it matter?
The slit is made from a 2mm thick plate of fused silica. This material offers two key advantages:
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Durability: It is mechanically robust and easy to clean without risk of damage.
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UV Transparency: It transmits light well into the ultraviolet portion of the spectrum (down to ~375 nm), allowing for astrophysical studies in wavelengths that are inaccessible with standard glass.
Does the Star’Ex GEN2 slit come with a holder?
No, the slit is delivered without its 3D-printed support. You will need to either 3D print the support part yourself using the plans provided by the manufacturer or design a custom holder for your specific instrument.
Can I use the 4mm slit length on the Star'Ex GEN2 to get a spectrum of the Orion Nebula (M42)?
Yes. The long 4mm slit length is specifically designed for capturing spectra of objects with large angular sizes, such as the Orion Nebula (M42) or comets. This allows you to study how the spectral characteristics change across different regions of the nebula in a single exposure.
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| Product |
4-Position Reflective Slit (GEN2) |
| Slit Widths |
14 µm, 20 µm, 26 µm, 32 µm |
| Central Pinhole Diameter |
25 µm |
| Slit Length |
4 mm |
| Substrate Material |
Fused Silica (Synthetic Quartz) |
| Substrate Dimensions |
16 mm x 16 mm |
| Substrate Thickness |
2 mm |
| Coatings |
Anti-reflective (one side), Opaque Chromium (slit side) |
| Compatibility |
Star’Ex Spectrographs, custom instruments |
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Star’Ex GEN2 4-Position Slit
× 1
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Shelyak 1-Year Warranty
