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Corona Borealis (FMA180 R5).jpg
This is a portrait of the faint but distinctive northern spring constellation of Corona Borealis, the Northern Crown, located between Böotes and Hercules. The framing includes the two famous variable stars in CrB: R Coronae Borealis and T Coronae Borealis, to illustrrate their location and brightness (the latter as of early May 2024).
Details on the two stars:
- R CrB is a "reverse nova," as it normally shines at magnitude 6, as it is here, just visible to the naked eye. But unpredictably (every few months or years) the star drops to as faint as magnitude 14, too dim to see in even modest-sized telescopes. R CrB is a yellow giant star, and the cause of the dimming is thought to be a build up of dark carbon soot in the aging star's atmosphere. R CrB is about 4500 light years away.
- T CrB is the opposite. Dubbed the Blaze Star, it normally shines at a dim magnitude 10.8, as it is here. But periodically, about every 80 years, it blazes up to magnitude 2 to 3, bright enough to be easily visible to the unaided eye. It is a cataclysmic variable or recurrent nova. T CrB is a binary star with a red giant orbiting an odd blue dwarf which is drawing material off the bloated red giant. Every few decades enough red giant material accumulates around the blue dwarf that the material undergoes a sudden thermonuclear explosion, brightening the system but leaving the dwarf star intact. This shows T CrB before its expected outburst in 2024. T CrB is 2700 light years away.
Technical:
This is a stack of 40 x 2-minute and 1.5-minute exposures with the Askar FMA180 Pro astrographic refractor (with 180mm focal length) at f/4.5 and the Canon R5 at ISO 1600. Tracked but unguided on the Astro-Physics AP400 mount. Taken from home May 3, 2024.
Details on the two stars:
- R CrB is a "reverse nova," as it normally shines at magnitude 6, as it is here, just visible to the naked eye. But unpredictably (every few months or years) the star drops to as faint as magnitude 14, too dim to see in even modest-sized telescopes. R CrB is a yellow giant star, and the cause of the dimming is thought to be a build up of dark carbon soot in the aging star's atmosphere. R CrB is about 4500 light years away.
- T CrB is the opposite. Dubbed the Blaze Star, it normally shines at a dim magnitude 10.8, as it is here. But periodically, about every 80 years, it blazes up to magnitude 2 to 3, bright enough to be easily visible to the unaided eye. It is a cataclysmic variable or recurrent nova. T CrB is a binary star with a red giant orbiting an odd blue dwarf which is drawing material off the bloated red giant. Every few decades enough red giant material accumulates around the blue dwarf that the material undergoes a sudden thermonuclear explosion, brightening the system but leaving the dwarf star intact. This shows T CrB before its expected outburst in 2024. T CrB is 2700 light years away.
Technical:
This is a stack of 40 x 2-minute and 1.5-minute exposures with the Askar FMA180 Pro astrographic refractor (with 180mm focal length) at f/4.5 and the Canon R5 at ISO 1600. Tracked but unguided on the Astro-Physics AP400 mount. Taken from home May 3, 2024.
- Copyright
- © Alan Dyer/AmazingSky.com
- Image Size
- 8192x5464 / 16.6MB
- www.amazingsky.com
- Contained in galleries
- Stars, My Latest, Various Constellations