Optolong Ultra High Contrast UHC Light Pollution Reduction Filter

In this review the Optolong Ultra High Contrast UHC filter is judged as a practical, affordable accessory for amateur astronomers who want clearer views of emission nebulae from light-polluted skies. The bottom line: this 2in UHC filter improves contrast by selectively blocking common city lights while preserving nebular emission lines, so it is most useful for visual observers using small to medium telescopes who need a straightforward way to boost nebula detail without complex equipment.

Key Features

• UHC broadband design: Blocks mercury and sodium lamp emissions and much skyglow while allowing nebular lines to pass for better contrast on emission nebulae.
• High transmission glass: Maintains strong light throughput at key wavelengths so small telescopes still deliver bright, detailed views.
• Targeted wavelength support: High transmittance at OIII, H beta, Ha and SII regions preserves the important emission lines of many deep-sky objects.
• Needle-sharp stars: The optical quality of the filter glass keeps star images crisp so familiar star fields remain usable for framing and navigation.
• 2in format: Fits standard 2in visual focuser assemblies, making it easy to add to existing eyepiece setups without adapters.

Who It's For

The Optolong UHC is aimed at backyard observers using small to mid-size telescopes, particularly those who live in suburban or semi-urban areas and want to pull more contrast from emission nebulae. Visual observers who want a simple, plug-in solution to reduce the impact of common street lighting will find this filter useful.

It is not designed as a specialized narrowband imaging filter for long-exposure astrophotography; those seeking highly selective imaging filters or solutions for large professional scopes should look elsewhere. This filter excels as a visual aid rather than a dedicated camera filter.

Pros & Cons

Pros

• Significantly improves nebula contrast under light-polluted skies by blocking common lamp lines.
• High transmission glass keeps views bright enough for small telescopes and preserves nebular detail.
• Optical quality maintains sharp stellar images, so star fields stay crisp when the filter is in place.

Cons

• As a broadband UHC it is less selective than narrowband imaging filters and not ideal for dedicated astrophotography of faint targets.

Specifications

Filter type	UHC (Ultra High Contrast) broadband
Size	2in
Target transmissions	High at OIII (496nm, 500nm), H beta (486nm), Ha (656nm), NII (654nm, 658nm), SII (672nm)
Intended use	Visual deep-sky observation, nebula contrast enhancement
Optical quality	High-quality filter glass for sharp star images
Best with telescopes	Small to mid-size telescopes (works from 2in/50mm and up)

Our Verdict

The Optolong Ultra High Contrast UHC 2in filter is a solid, value-oriented tool for visual observers who want clearer nebula views from light-polluted sites. Its broadband rejection of common lamp lines combined with high transmission at key emission wavelengths delivers noticeable contrast gains without dimming targets excessively, making it a worthwhile add-on for casual and serious backyard astronomers alike.

Frequently Asked Questions

Will this filter work with my 2in eyepieces?
Yes, the filter is a 2in format intended to fit standard 2in visual focuser setups and most 2in eyepieces without additional adapters.

Is this filter suitable for astrophotography?
It is primarily a visual UHC broadband filter; photographers seeking narrowband imaging performance for faint targets will prefer more selective imaging filters.

Which objects benefit most?
Emission nebulae such as the Orion Nebula and planetary nebulae benefit most because the filter passes OIII, Ha and related emission lines while reducing skyglow.