OPTOLONG 1.25ft UV/IR Cut Filter for CCD Digital Astrophotography

In this review the OPTOLONG 1.25' UV/IR Cut Filter is assessed as a practical, no-nonsense accessory for CCD astrophotography. It is aimed at amateur and advanced hobbyist imagers who need a simple way to remove unwanted ultraviolet and infrared contamination without altering optical performance. The single biggest reason to consider this filter is its targeted transmission: very high pass efficiency across key emission lines (including H-beta, OIII and H-alpha) while providing comprehensive blocking of troublesome wavelengths, which translates to cleaner color balance and sharper narrowband detail on CCD cameras.

Key Features

• High transmission at H-beta: The filter passes 96% at 486nm so H-beta features remain bright and well defined in CCD captures.
• Strong OIII throughput: With 95% transmission at 496nm and 92.5% at 501nm, OIII emission is preserved for contrast in planetary nebulae and emission regions.
• Excellent H-alpha response: A 98% transmission at 656nm helps preserve the brightest red emission without sacrificing detail.
• Dual pass ranges: The filter passes light from about 450 to 520nm and from 620nm upward, which supports key visual and imaging bands while excluding interfering bands.
• Durable coatings and material: Scratch-resistant, humidity and aging resistant glass with hardened multi-coatings keeps the filter stable over time and maintains image quality.

Who It's For

This filter is best for CCD astrophotographers using refractors or small to medium telescopes who want a simple way to cut UV/IR and boost contrast on emission-line targets. It is particularly useful for those capturing nebulae and deep sky objects where H-beta, OIII and H-alpha contribute to the structure and color balance.

Those seeking variable narrowband isolation or filters optimized for broadband DSLR imaging may want to consider alternate filters; this product is specialized for CCD systems and for maintaining parfocal alignment with other Optolong filters in a research or imaging workflow.

Pros & Cons

Pros

• High transmission on key emission lines gives bright, contrasty nebular detail.
• Complete blocking of unwanted wavelengths reduces color contamination from UV and IR.
• Durable, scratch-resistant glass and coatings resist humidity and aging for long-term use.
• Parfocal with other Optolong filters, simplifying filter swaps during imaging sessions.

Cons

• Not a replacement for specialized narrowband filters when extreme isolation of one line is required.

Specifications

Filter type	UV/IR cut for CCD astrophotography
Mount size	1.25' filter
Glass thickness	1.85 mm
Transmission highlights	96% at 486 nm, 95% at 496 nm, 92.5% at 501 nm, 98% at 656 nm
Pass bands	Approximately 450-520 nm and 620 nm upward
Durability	Scratch-resistant, humidity and aging resistant
Packaging	High-quality, long-lasting filter box

Our Verdict

The OPTOLONG 1.25' UV/IR Cut Filter is a well-built, practical tool for CCD imagers who need reliable UV and IR suppression without compromise to optical performance. Its high transmission at H-beta, OIII and H-alpha plus durable coatings make it good value for users focused on emission-line deep sky imaging using small telescopes or refractors.

Frequently Asked Questions

Will this reduce image sharpness?
The filter is diffraction limited and designed not to reduce optical performance, so image sharpness should be preserved.

Is it suitable for DSLR sensors?
It is optimized for CCD astrophotography; DSLRs may benefit but specialized broadband or narrowband DSLR filters could be preferable depending on use.

Does it resist humidity and aging?
Yes, the filter is completely resistant against high humidity, scratches and aging effects according to the manufacturer.