NGC 3166 & NGC 3169 – An Interacting Galaxy Pair in Sextans (LRGB)

LRGB processing of the Telescope Live T-17 dataset (CDK17, Rancho Hidalgo, New Mexico) by Bernard Miller.

Integration: 19.7 h — L 23 × 1200 s, R/G/B 12 × 1200 s each (4 elongated or soft L subs rejected after measurement).

Workflow (PixInsight, after Philippe Bernhard's LRGB scheme):

- Star alignment and integration of the calibrated subs (PSF signal weighting, ESD rejection)

- Gentle polynomial gradient removal, background neutralization

- BlurXTerminator (correct only on RGB, then sharpening), StarXTerminator, NoiseXTerminator

- Colour taken from the linear RGB, white balance on star cores

- MaskedStretch + HDRMultiscaleTransform on the luminance; core of NGC 3166 enhanced under a mask (HDRMT, soft LHE, light unsharp mask) to reveal its inner dust spiral

- Stars reshaped separately for a smooth, natural brightness progression, one colour per star

About 65 million light-years away in Sextans and separated by some 160,000 light-years, the lenticular NGC 3166 and the spiral NGC 3169 are gravitationally interacting: NGC 3169's disk is warped and wrapped in faint tidal plumes, while NGC 3166 shows a ring of dust around its bright core. Small blue NGC 3165 sits nearby.

FR : traitement LRGB des données Telescope Live (T-17), 19,7 h d'intégration.