Reference
Filter mapping
Everyone names filters differently: Ha 3nm, H-alpha, Hα, H. So that all of them land in one stack, every frame's filter name is resolved to a canonical filter.
The canonical filters
| Canonical | Covers |
|---|---|
L | Luminance, Lum, L, clear with IR/UV cut, UV/IR cut |
R G B | Red, Green, Blue and single letters |
HA | Ha, H-alpha, Halpha, Hα, HII, hydrogen, and bandwidth forms such as "Ha 3nm" |
OIII | OIII, O3, Oiii, oxygen |
SII | SII, S2, Sii, sulphur |
HB NII | H-beta, N2 |
CLEAR | Clear, none, empty, "no filter" without an IR cut |
DUO | Dual- or multi-band filters (L-eNhance, L-eXtreme, ALP-T, NBZ, "dual band") |
OSC | A one-shot-colour camera with a luminance or clear filter |
IR UV U V I Z Y | Photometric and infrared filters, used only if the project lists them |
How a name is resolved
- The text is normalised: case, spaces, punctuation and Greek letters are ignored.
- The project owner's override map wins outright.
- Then your own mapping, the one you confirm in the plugin when you join.
- Then the built-in alias table and pattern rules (vendor names and bandwidths such as "Antlia 3nm SII" included).
- Single letters (
H,O,S,L,R,G,B) are accepted only when the project lists that filter. - A Bayer sensor with a luminance, clear or empty filter becomes
OSC. - If the filter header is missing, the file name is tried.
The plugin fetches the alias table and shows its suggestion in the mapping grid, so you usually only confirm.
When a name is not recognised
The frame is quarantined, not rejected: it waits. Once you or the project owner map that name, the frame continues automatically. See unknown filter, ambiguous filter and filter not in project.
Bandwidths and colour cameras
By default Ha 3nm and Ha 12nm go into one HA stack. The owner can keep them apart; the stacks are then labelled by bandwidth, for example HA 3 nm, and a frame whose bandwidth is not stated goes to HA (bandwidth unknown). R, G and B from a colour camera are kept in separate streams marked (OSC) unless the owner merges them.