Why choose the Antlia 7nm Prime filter set over a 3nm or 5nm set?
A 7nm bandpass offers a balance between light pollution rejection and signal strength, especially for faster optical systems. While tighter filters (3nm) provide more contrast in heavily light-polluted areas, the Antlia 7nm Prime filters allow more signal through, which is beneficial for faster f/ratio scopes down to f/2 and can result in shorter exposure times.
How does the Antlia 7nm Prime SHO set perform with a fast f/2 telescope?
Antlia states that, with their wider FWHM, 7nm Prime filters can be used with nearly all systems as fast as f/2 with minimal loss in emission signal.
Will I see halos around bright stars with the Antlia 7nm Prime filters?
Antlia has engineered these filters to minimize halos. Key features that contribute to this are:
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Single Substrate: A single, non-glued substrate eliminates internal reflections.
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Steep Spectral Profile: The steep spectral profile minimizes halos around bright stars.
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Edge Blackening: The unmounted filters are edge blackened to eliminate internal reflections from stray light.
Can I use the Antlia 7nm Prime filters for visual observing?
No. Antlia lists night visual observation as not recommended for these filters. They are designed for narrowband astrophotography.
What is the benefit of the Antlia H-alpha filter also passing NII emission lines?
Many emission nebulae, such as the Orion Nebula (M42) and the Lagoon Nebula (M8), emit strongly in both H-alpha (hydrogen) and NII (nitrogen). With its 7nm bandpass, the H-alpha filter passes the H-alpha line at 656.3nm and the NII lines at 654.8nm and 658.3nm, so it records the combined signal.
How will this Antlia 7nm SHO set help me image the Pillars of Creation in the Eagle Nebula (M16) from my suburban backyard?
The Eagle Nebula (M16) is a classic SHO target, rich in ionized Sulphur, Hydrogen, and Oxygen. From a suburban location, the Antlia 7nm Prime filters can be used in light-polluted areas, as Antlia states. The >OD4 blocking and 7nm bandpass minimize interference from wavelengths outside each passband, which helps separate the structure of the nebula from a bright sky background for a Hubble Palette image.
