What kind of light pollution does the Chroma LoGlow filter block?
The Chroma LoGlow is designed to block common spectral lines from artificial lighting sources, specifically metal-halide and vapor lamps (like sodium and mercury vapor). It selectively notches out these wavelengths while transmitting the rest of the visible spectrum, which helps to darken the sky background and improve contrast on broadband targets like galaxies and star clusters.
Will I need to refocus when switching between the Chroma LoGlow and other Chroma filters?
Yes, you will need to refocus. The LoGlow filter is made with 1.1 mm thick glass, while all other Chroma astronomy filters use a 3.0 mm substrate. This difference in thickness means the LoGlow is not parfocal with the rest of the Chroma astronomy line, requiring a focus adjustment when you switch filters.
Is the Chroma LoGlow filter suitable for an f/2 telescope?
No. Chroma designs the LoGlow for f/4.0 or slower. At very fast focal ratios like f/2, the steep light cone causes the filter's bandpass to shift towards blue wavelengths. This can move the filter's blocking bands away from the intended light pollution lines, reducing its effectiveness. For an f/2 system, you would need a filter specifically designed for that focal ratio.
I'm imaging the Andromeda Galaxy (M31) from my suburban backyard. Is the LoGlow a good choice?
Yes, this is an excellent application for the Chroma LoGlow filter. The Andromeda Galaxy (M31) is a broadband target, meaning it emits light across the entire visible spectrum. The LoGlow will help suppress the sky glow from your suburban location, increasing the contrast between the galaxy and the background sky while preserving the natural colors of its stars and dust lanes.
How does the Chroma LoGlow affect color balance in my astrophotos?
The LoGlow is designed to provide balanced color across the visible spectrum. By targeting only specific, narrow emission lines from artificial lights, it allows the majority of the continuous spectrum from stars and galaxies to pass through. This results in images that are easier to color balance during processing.
Can I use the Chroma LoGlow filter for visual observing?
While the filter is primarily designed for astrophotography, it can be used visually. It will help darken the sky background and may improve contrast on some objects, particularly from light-polluted areas. However, its effects will be more subtle to the eye than they are to a camera sensor during a long exposure.
