NGC 2403 / C7

Designation(s)NGC 2403, C7
Object Type(s)Galaxy
Relevant Catalog(s)All (Chron), Caldwell, NGC
Obs. Lat/Long42° 17', 073° 57'
ConstellationCamelopardalis
Date and Time Observed2023-11-05 05:37:00
Instrument8" EdgeHD SCT
CameraASI294mc-Pro
Image DetailsUp is 271.8 degrees E of N. Transparency: Good. Seeing: Fair. Total integration time was 30m. Exposures 15s@305g, UV/IR Cut Filter. Darks subtracted, no flats. Dithered and recentered in SharpCap. No guiding..
DescriptionLarge, intermediate spiral galaxy in Cam, discovered by William Herschel on 1 November 1788. GA Tammann and Allan Sandage calibrated Cepheid variables in NGC 2403 in a.1968 paper using the 200" Mt Palomar Telescope, making it the first galaxy beyond the Local Group within which Cepheid's were used in the Hubble constant distance calculation. Analysis of Cepheid's increased the estimated distance to approximately 8 million light years. Similar to M33, NGC 2303 contains numerous HII star-forming regions, one of which is designated NGC 2404. The gallery includes an additional, heavily stretched version of the image that makes these regions more visible.
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