Beta Muscae — Double Star in Musca
About Beta Mus
Description
Beta Muscae is a blue-white star of spectral type B2.5V at magnitude 3.05, the second brightest star in Musca. Located about 341 light-years from Earth, it is a close binary system with two blue stars orbiting every 194 years. Its combined luminosity is about 4,100 times solar.
Observing Tips
Beta Mus lies in the small constellation Musca just south of the Southern Cross. A moderate telescope can split the binary pair at their current separation. The dark Coal Sack nebula lies nearby. Only visible from the southern hemisphere. Best observed March through June.
History
Beta Muscae has no traditional proper name. Musca is one of the constellations created by Petrus Plancius from the observations of Dutch navigators and was originally known as 'Apis' (the Bee).
Fun Facts
Beta Mus is one of the more easily resolved bright binaries in the southern sky, with the two components slowly orbiting over nearly two centuries.
Observe
1Physical Properties
2Position & Identifiers
3How easy to split?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | V. hard+ | V. hard+ | V. hard+ |
| 150 mm Newton 150mm Newt. | Hard | Hard | Hard |
| Celestron C8 (203 mm SCT) C8 203mm | Hard+ | Hard+ | Hard+ |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
5Multiple Star System
Separation over time
Apparent separation over time, computed from ORB6 orbital elements. Steep curves indicate fast-changing pairs — catch them while they're splittable.
Eyepiece View
A: 3.0 · B: 4.0 · Sep: 0.9″ · PA: 58° · N up, E right
Unresolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″
Explore
7
Size Comparison
8
Compare Stars
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Spectral Classification
10
Hertzsprung-Russell Diagram
11
Stellar Lifecycle
12
Blackbody Spectrum
13
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
14
Stellar Fusion
Discover
15Stellar Notes
16
Light Travel Time Machine
17
Relativistic Travel
Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
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