Chroma Technology SII Ha OIII - 3nm Filter Set

Frequently Asked Questions about the Chroma HA3LRGB Filter Set

How does the Chroma HA3LRGB compare to Astrodon filters?

Chroma and Astrodon are both considered premium filter manufacturers, and independent testing shows comparable optical quality between the two brands. The primary differences are price and availability — Chroma filters typically cost $500–700 less than equivalent Astrodon sets for larger sizes. Both use 3mm substrates and hard coatings. Deep Space Products carries Chroma filters and can help you evaluate whether they're the right choice for your imaging goals.

Should I choose 3nm, 5nm, or 8nm H-alpha?

The bandwidth affects contrast and exposure time. A 3nm filter provides maximum contrast and sky background rejection — ideal for light-polluted skies, moonlit nights, or when capturing the finest nebula detail. The tradeoff is longer exposures compared to 5nm or 8nm filters. For portable setups with limited imaging time, 5nm offers a good balance. For observatory or remote imaging where integration time is less constrained, 3nm delivers superior results.

Are Chroma filters parfocal?

Yes. All Chroma astronomy filters within a set are parfocal, meaning you can swap between filters without adjusting focus. This is essential for automated imaging sessions. Note that Chroma filters may not be perfectly parfocal with filters from other manufacturers, even if substrate thickness is similar.

What focal ratio can I use with Chroma filters?

Chroma's standard astronomy filters are designed for optical systems f/4 and slower. For faster systems (f/3 or f/2), Chroma offers custom coatings optimized for the increased angle of incidence. If you're imaging with a fast astrograph, contact Deep Space Products to discuss whether custom filters are needed for your setup.

Do Chroma filters work with both CCD and CMOS cameras?

Yes. Chroma filters are compatible with both CCD and CMOS sensors. The anti-reflection rear coating minimizes reflections between the filter and sensor surface, reducing artifacts that can occur with some filter/camera combinations.

What size filter do I need?

Filter size depends on your sensor dimensions and optical speed. Smaller sensors (APS-C and below) with moderate focal ratios can use 1.25" or 31mm filters. Full-frame sensors and fast optics require 2"/50mm filters to avoid vignetting. The 50×50mm square format is available for large-format filter wheels and custom imaging trains. Deep Space Products can help you determine the correct size based on your specific camera and optical train — contact us to discuss your configuration.

Does Deep Space Products offer support for Chroma filter purchases?

Deep Space Products is an authorized Chroma Technology dealer. We carry the full range of Chroma filter sizes and can provide guidance on filter selection, sizing, and compatibility with your imaging system. For questions about integrating Chroma filters into a complete imaging setup, reach out to our team.

How do I handle and clean Chroma filters?

Handle Chroma filters by the edges only. Remove loose particles with a bulb blower or filtered compressed air. If cleaning is necessary, gently wipe with anhydrous alcohol and lint-free optical wipes, using a fresh surface with each pass. The hard sputtered coating is durable, but avoid touching coated surfaces directly.