IC 2574 in H-alpha and continuum light
IC 2574 (also known as Coddington's Nebula) is a very faint dwarf galaxy in Ursa Major. It is a member of the M81 group, one of the nearest groups to the local group, and contains very active star-forming regions showing strong H-alpha emissions. The distance from earth is about 12.8 million light years and the diameter of the visible disk is about 50,000 light years.
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By toggling between the images (click on the button) it can be seen that the HII regions (reddish) correlate with bluish regions. That's because the HII gas clouds typically contain many young (blue) stars which are also responsible for the ionization. Furthermore the HII regions also emit [OIII] and H-beta light
which is collected by the blue filter.
Image data
| FOV: | 0.44° × 0.44° (full view) | ||||||||
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| Date: | 2021-2022 | ||||||||
| Location: | Pulsnitz, Germany | ||||||||
| Instrument: | 400mm Newton at f=1520mm | ||||||||
| Camera Sensor: | Panasonic MN34230 | ||||||||
| Orientation: | North is up (approximately) | ||||||||
| Scale: | 0.8 arcsec/pixel | ||||||||
| Total exposure times: |
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Image processing
All image processing steps are deterministic, i.e. there was no manual retouching or any other kind of non-reproducible adjustment. The software which was used can be downloaded here.Image processing steps where:
- Bias correction, dark current subtraction, flatfield correction
- Alignment and brightness calibration using stars from reference image
- Stacking with masking unlikely values and background correction
- Denoising and deconvolution
- Color composition
- Dynamic range compression using non-linear high-pass filter
- Tonal curve correction
