Theta Arae — Star in Ara
Observe
1Physical Properties
Magnitude
3.66
Spectral Type
B2 IB
supergiant
Star Color
Blue
(B-V -0.08)
Distance
812 ly
3How easy to spot?
Sign in
and configure your equipment and default location to see a personalized row.
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Easy | Medium+ | Medium+ |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Easy
Medium
Hard
Very hard
Impossible
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
Best season
May – Jul
(peak: Jun)
5Survey Image
Loading survey image…
Explore
7
Size Comparison
Querying VizieR for stellar data…
8
Compare Stars
9
Spectral Classification
10
Hertzsprung-Russell Diagram
Loading HR 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
Listed by Buscombe and Morris (M.N.R.A.S. 121, 268, 1960) and by Buscombe and Kennedy (M.N.R.A.S. 124, 196, 1962) among | Sco-Cen stars. Buscombe now rejects membership, while Eggen (ApJ, 188, 59, 1974) includes it as a member of the | Pleiades group.
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.
NGC 6584
Globular cluster — dense ball of ancient stars
Globular Cluster
mag 9.2
2.8°
Telescopium
V539 Ara
Eclipsing binary, period 3.2d
Variable Star
mag 5.92
4.3°
Ara
IC 4651
Rich open cluster
Open Cluster
mag 6.9
6.7°
Ara
IC 4796
Bright spiral galaxy
Galaxy
mag 12.30
8.7°
Telescopium
Explore Nightbase
Related knowledge, tools, and stories — no observation planning required.
Arthur Eddington
1919 eclipse expedition confirming general relativity; first theory of stellar interiors; the Eddington limit
Biography
The Hertzsprung-Russell Diagram — Reading Stars Like a Map
The HR diagram turns the night sky into a physics map: every named star has a spot, every spot tells you mass, age, and fate. A guide for amateur observers.
Article
Ara
Mythology, bright stars, and deep-sky highlights.
Constellation
