NGC2403 Galaxy
NGC2403 is a spiral galaxy located 8 million light-years from Earth. It contains numerous Hii star-forming regions, visible as red knots in this image. Stretching 90,000 ligh-years across, it is similar to galaxy M33. North is at the top.

Scope/Mount: TS-Optics PhotoLine 130mm F7 APO Refractor with Astro-Tech AT2FF Field-flattener, Celestron CI-700 Mount
Camera: ZWO ASI1600MMC monochrome with ZWO LRGB and Ha, Oiii, Sii filters
Guiding: QHY5L-IIM through Orion Deluxe OAG, PHD guiding software
Exposure: L:(24) 300 secs @ gain=300, Ha(12) 300 secs @ gain=300, RGB: each channel (10) 120 sec @ gain=200
Software: Nebulosity, Pixinsight, NoiseXterminator
Comment: 03/21/2025, Tierra del Sol, CA, good conditions. Palette = LRGB plus Ha used as mask.