Astronomik UHC 1.25″ filter
Overview
This narrow band UHC filter represents an ideal solution for observing gaseous and planetary nebulae from urban environments with light pollution. The filter is also an excellent choice for comet observation, where it can significantly enhance the visibility of their characteristic structures.
How it works
The filter operates on the principle of selective blocking of unwanted spectral lines. It completely eliminates emission lines from low-pressure and high-pressure mercury (Hg) and sodium (Na) discharge lamps, which are the main sources of light pollution in urban environments. Simultaneously, it blocks airglow bands, which dramatically improves contrast between the sky background and the observed object.
The filter's transmission band is designed to include key emission lines of hydrogen and oxygen that are characteristic of gaseous nebulae. The filter band also contains emission lines that occur predominantly in the tail section of comets, making it a universal tool for various types of observation.
Technical specifications
- Filter diameter: 1.25″ (31.75mm)
- Filter type: Ultra High Contrast (UHC) narrow band
- Transmission rate: 97%
- Mount material: Aluminum
- Coating: Multi-layer anti-reflection
- Thread: Standard 1.25″ astronomical filter thread
Optimal telescope compatibility
The Astronomik UHC 1.25″ filter is optimized for telescopes with focal ratios from f/3 to f/15 with apertures up to 5″ (125mm). With larger telescopes, its ability to increase contrast of observed objects is also significantly utilized.
Key features and benefits
- Selective blocking of mercury and sodium emission lines
- Enhanced contrast for nebulae and comets
- Airglow suppression for darker sky background
- High 97% transmission rate
- Durable aluminum housing
- Multi-layer anti-reflection coating
- Standard 1.25″ eyepiece compatibility
Applications
Deep sky observation
Perfect for observing emission nebulae, planetary nebulae, and supernova remnants. The filter enhances H-alpha and OIII emission lines while suppressing light pollution.
Comet observation
Enhances visibility of comet tails and coma structures by transmitting characteristic emission lines while blocking interfering wavelengths.
Urban astronomy
Enables productive deep sky observation from light-polluted urban and suburban locations by dramatically reducing the impact of artificial lighting.
Performance characteristics
Thanks to its high transmission of 97% and quality multi-layer coating, the filter provides excellent light transmission while maintaining selective blocking of unwanted spectral lines. The aluminum mount ensures durability and long-term reliability of use.
