Deneb
HIP 102098; Alpha Cygni; 50 Cygni
About Deneb
Description
Deneb is a blue-white supergiant of spectral type A2Ia at magnitude 1.25, the brightest star in Cygnus and one of the most luminous stars visible to the naked eye. Its distance is uncertain but estimated at 1,500-2,600 light-years, making its intrinsic luminosity between 55,000 and 196,000 times solar. Deneb is evolving toward becoming a red supergiant and will eventually explode as a supernova.
Observing Tips
Deneb marks the top of the Northern Cross asterism in Cygnus and is the faintest vertex of the Summer Triangle (with Vega and Altair). Despite appearing dimmer than Vega and Altair, it is vastly more luminous — just much farther away. Its location in the Milky Way makes the surrounding field spectacular in binoculars. Best observed June through November.
History
The name Deneb comes from the Arabic 'dhanab al-dajajah,' meaning 'the tail of the hen.' As the prototype A-type supergiant, Deneb has been extensively studied. It will become the pole star (roughly) around AD 9800 as Earth's axis precesses. In Chinese astronomy, Deneb represents a bridge across the Milky Way.
Fun Facts
If Deneb were at the same distance as Sirius (8.6 light-years), it would be roughly as bright as a half Moon and would cast visible shadows at night. Its exact distance remains one of the most debated values in stellar astronomy — Hipparcos measurements have large error bars for such a distant star.
Observe
1Physical Properties
Position & Identifiers
2How easy to split?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Hard | V. hard+ | V. hard |
| 150 mm Newton 150mm Newt. | Medium | Hard+ | Hard |
| Celestron C8 (203 mm SCT) C8 203mm | Medium+ | Medium | Medium |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
3Visibility
Set a location in User Settings to see visibility data.
4Multiple Star System
Eyepiece View
A: 1.2 · B: 11.7 · Sep: 75.6″ · PA: 105° · N up, E left
Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″
Explore
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Size Comparison
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Compare Stars
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Stellar Lifecycle
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Spectral Classification
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Hertzsprung-Russell Diagram
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Blackbody Spectrum
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Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
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Stellar Fusion
Discover
14Stellar Notes
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Light Travel Time Machine
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Relativistic Travel
Survey Image
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Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
