NGC 2403 (Camelopardalis)
Fig. 1 - One of the brightest non-Messier galaxies: NGC 2403 in Camelopardalis, photographed with a 16-inch f/4.5 Dob on an equatorial platform.
| Object name: | Constellation: | Coordinates: | Apparent size: | Visual brightness: |
|---|---|---|---|---|
| NGC 2403 | Camelopardalis | 23.4' x 11.8' | 14' | 8.2 mag |
The intermediate spiral galaxy NGC 2403 (also known as Caldwell 7) in the constellation Camelopardalis. NGC 2403 is a transitional type between the spiral galaxies and the barred spiral galaxies and contains numerous star-forming H II regions, one of the largest known H II regions being NGC 2404 in the northern spiral arm. The galaxy NGC 2403 is an outlying member of the M81 galaxy group and is approximately 8-10 million light-years from Earth. It is about 50,000-70,000 light-years in diameter and bears similarity to Messier 33. NGC 2403 was discovered by William Herschel in 1788 (source: Wikipedia).
Exposure time: 2h 2min (41x approx. 3min) at ISO 800, taken on December 18 / 19, 2020. Processing with DeepSkyStacker and Photoshop. No calibration frames were taken.
Equipment: Canon EOS 450D Baader modified camera, TeleVue Universal Paracorr coma corrector, 16" f/4.5 "Ninja" dobsonian telescope riding on a dual-axis Tom Osypowski equatorial platform, Lacerta MGEN autoguider, Lacerta off axis system.
Field of view comparison: image of the moon with the same equipment.
Fig.2 - Some of the brighter H II regions in NGC 2403. Annotations according to: Sivan, Petit, Comte, Maucherat. Optical HII regions in NGC 2403. Astron. Astrophys. 237, 23-35 (1990).
Fig. 3 - Search chart for NGC 2403. Copyright 2025 'The Mag-7 Star Atlas Project', www.siaris.net.