How do I use the Antlia ALP-T set with my color camera to get separate channels?
You capture two sets of images, one with the Ha/OIII filter and another with the SII/Hb filter. In post-processing software, you can split the channels from each set. For example, the data from the Ha/OIII filter can be separated to isolate the red pixels (Ha) and the green/blue pixels (OIII). A similar process with the second filter separates SII and Hb, giving you four distinct monochrome images to combine into a false-color master.
What is the advantage of the SII & H-beta filter in the Antlia ALP-T set?
While Sulfur-II (SII) is crucial for the popular "Hubble Palette," the inclusion of Hydrogen-beta (H-beta) provides additional data that can reveal structures not visible in OIII. H-beta is the second most common hydrogen emission line after H-alpha and is prominent in certain objects. This gives you more flexibility in processing and can lead to richer, more detailed final images.
Will the Antlia ALP-T filter set work well with my f/5 refractor?
Yes. These filters are recommended for optics slower than f/4, and f/5 is within that range.
Can I use these Antlia filters for visual observation of nebulae like the Orion Nebula (M42)?
No. Night visual observation is not recommended; these filters are made for imaging with a camera.
How do the 3nm and 3.5nm bandwidths on the ALP-T filters help in light-polluted skies?
The narrow bands pass light only close to the emission lines, so most artificial light, moonlight and airglow is blocked (≥OD4.5 from 300nm to 1100nm). Antlia designed the filters for Bortle 1 to Bortle 8 skies.
What kind of false-color palettes can I create with data from the Antlia ALP-T set?
With four channels (Ha, OIII, SII, Hb), your options are extensive. Popular choices include:
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S-H-O (Hubble Palette): Assign SII to Red, Ha to Green, and OIII to Blue.
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H-O-S: A common variation where Ha is mapped to Red for a more natural look.
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H-O-Hb: A creative palette that uses H-beta data, which can highlight different structures than SII.
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H-S-OHb: Another custom combination that blends multiple channels.
Antlia adds that you can use the narrowband data as a luminance layer to enhance a standard RGB color image of the same object.
Why does the Antlia Ha&OIII filter have different peak transmission values (90% and 82%)?
Antlia does not give a reason; 90% at 656.3nm and 82% at 500.7nm are its rated peak transmissions for each line. On a color camera with an RGGB Bayer pattern, OIII falls on twice as many green pixels as there are red pixels for H-alpha.
Are these Antlia filters safe for solar imaging?
No. Solar imaging is not recommended. Warning: do not look at the Sun with this filter directly; serious eye damage will result if you fail to observe the warning.
